WO2018073175A1

WO2018073175A1 - Compounds and pharmaceutical compositions thereof for use in the treatment of cystic fibrosis

Info

Publication number: WO2018073175A1
Application number: PCT/EP2017/076358
Authority: WO
Inventors: Katja Els Conrath; Olivier Frans Jozef Maria VAN DE STEEN; Piet Tom Bert Paul Wigerinck; Herman Augustinus De Kock
Original assignee: AbbVie S.à.r.l.; Galapagos Nv
Priority date: 2016-10-17
Filing date: 2017-10-16
Publication date: 2018-04-26

Abstract

The present invention provides the compound of the invention according to Formula I for use in the treatment of cystic fibrosis, in particular for use in the treatment of class III and/or IV mutations, and more particularly of class III mutations.

Description

COMPOUNDS AND PHARMACEUTICAL COMPOSITIONS THEREOF FOR USE IN THE

TREATMENT OF CYSTIC FIBROSIS.

FIELD OF THE INVENTION

[0001] The present invention provides the compound of the invention according to Formula I for use in the treatment of cystic fibrosis, in particular for use in the treatment of class III and/or IV mutations, and more particularly of class III mutations. The present invention also provides methods for the production of the compound of the invention, pharmaceutical compositions comprising the compound of the invention, methods for the treatment of cystic fibrosis by administering the compound of the invention.

BACKGROUND OF THE INVENTION

[0002] Cystic fibrosis (CF) is a recessive genetic disease (http://www.cff.org/AboutCF) caused by mutations in a gene on chromosome 7 encoding for the cystic fibrosis transmembrane conductance regulator (CFTR) protein, a cAMP-regulated anion channel expressed primarily at the apical plasma membrane of secretory epithelia. Clinical disease requires disease-causing mutations in both copies of the CFTR gene. (Rowe et al., 2005).

[0003] Approximately 1:3500 and 1:3000 infants born in the United States and in Europe, respectively, are affected by CF, resulting in ~ 75,000 cases worldwide , -30,000 of which are in the United States. Approximately 1,000 new cases of CF are diagnosed each year, with more than 75% of patients being diagnosed by 2 years of age. Nearly half the CF population is currently 18 years of age and older.

[0004] Predicted life expectancy of patients with CF has increased significantly in the last 20 years, e.g. from 29 years in 1992 to 41 years in 2013 (Bethesda and 800-344-4823, n.d.). In order to achieve greater incremental improvements in health and longevity, transformational disease-modifying therapies are required. Recent predictions suggest that if the mortality rate continues to decline at the rate observed between 2000 and 2010, the median predicted survival of children diagnosed in 2010 will be more than 50 years of age (MacKenzie et al., 2014).

[0005] Over 1900 CF disease-causing mutations have been identified through sequence analysis of the CFTR gene of CF chromosomes (Kerem et al., 1989), and have been classified according to their phenotypic consequences and belong to synthesis, maturation, regulation, conductance, reduced number due to quantity and reduced number due to stability classifications: Class I which results in (almost) complete absence of CFTR protein synthesis; Class II which result in arrested maturation and intracellular localization defect of the CFTR protein; Class III: result in inhibition of regulation with defective activation of the chloride ion transport function; Class IV: result in reduced conductance of chloride ions; and Class V: result in reduced CFTR protein synthesis.

[0006] CFTR dysfunction results in thick, viscous secretions, affecting the lungs, reproductive tract and most exocrine glands, notably the pancreas, intestine, sweat gland, and bile duct. Individuals with CF present with multisystem disease involving several or all of these organs. However pulmonary disease remains the leading cause of morbidity and mortality in CF resulting from dehydration of the airway surface liquid and impaired airway mucociliary clearance, which leads to cycles of bacterial infection, chronic inflammation, bronchiectasis and progressive decline in pulmonary function (Lubamba et al., 2012; Okiyoneda et al., 2013; O'Sullivan and Freedman, 2009; Pittman and Ferkol, 2015).

[0007] Current CF drug discovery efforts are focusing on developing compounds which may modulate CFTR. The first class, named Correctors, helps to overcome the folding defects of the mutated CFTR protein to promote its maturation resulting in higher cell surface expression. Corrector compounds are being used to treat Class II mutations, such as F508del-CFTR. An example of such corrector is VX-809. The mutated protein F508del-CFTR, in addition to the Class II mutation effect (decreased maturation and intracellular localization defect of the CFTR protein) also has reduced chloride ion conductance.

[0008] A second class of compounds, called Potentiators, helps to overcome the defective regulation and/or conductance of the protein by increasing the probability of channel opening on the membrane surface. CFTR potentiators improve the function of CFTR channels that have gating (Class ffl) or conductance (Class TV) mutations (Rogan et al, 2011). There is additional evidence from in vitro studies that CFTR potentiators may also enhance the function of CFTR channels with Class Π mutations (V an Goor et al., 2009). Nevertheless, a potentiator can only have an effect if the expressed CFTR channel is already located on the cell membrane. Thus, CFTR potentiators alone are not able to treat Class I or II mutations, which are characterized by an absence or lack or synthesized CFTR protein. An example of a potentiator is VX-770, which is successful only in patients suffering from cystic fibrosis with a class IILTV defect such as e.g. G551D-CFTR gene defect, who represent 1-5% of all the cystic fibrosis patients (Van Goor et al, 2009), but has no significant therapeutic efficacy in patients having F508del-CFTR class II mutation (Flume et ah, 2012). That points to the need for customized treatments for sub-groups of patients suffering from cystic fibrosis, and such treatment depends on the nature of the mutation in the CFTR gene and the resulting defect in the CFTR protein.

[0009] In addition, as the modulation of CFTR protein mutations to promote proper protein folding is beneficial for the treatment of CF, other diseases mediated by CFTR may also be treated using CF treatment agents, such as for example, Sjogren's Syndrome (SS), an autoimmune disorder that results in symptoms of xerostomia (dry mouth) and keratoconjunctivitis sicca (KCS, dry eyes) which may originate from dysregulation of moisture producing glands throughout the body. Chronic obstructive pulmonary disease (COPD), or chronic obstructive airway disease (COAD), which is a progressive and irreversible airflow limitation in the airways is result of several physiologic abnormalities, including mucus hyper secretion and impaired mucociliary secretion. Increasing the anion secretion by CFTR potentiators have been suggested to overcome these phenotypic complexities with Sjogren's Syndrome by increasing the corneal hydration and by overcoming the impaired mucociliary secretion in COAD (Bhowmik A, et al. (2009) Vol. 103(4), 496-502; Sloane P, et al. PLOS One (2012) Vol 7(6), 239809 (1-13)).

[0010] Accordingly, there is a need for novel compounds able to modulate CFTR. In particular, the present invention discloses compounds for use as CFTR modulators for the treatment of cystic fibrosis. The present invention also provides methods for the preparation of these compounds, pharmaceutical compositions comprising these compounds and methods for the treatment of cystic fibrosis by administering the compounds of the invention.

SUMMARY OF THE INVENTION

[0011] The present invention provides the compound of the invention according to Formula I for use in the treatment of cystic fibrosis, in particular for use in the treatment of class HI and/or IV mutations, and more particularly of class III mutations.

[0012] Accordingly, in a first aspect of the invention, the compound of the invention according to Formula (I) shown below:

I

is provided for use in the treatment of cystic fibrosis, wherein the compound of the invention is dosed orally at a dose of between 25 mg to 1000 mg administered once (q.d.) or twice a day (b.i.d.), particularly between 50 mg to 600 mg , more particularly 62.5 mg, 125 mg., 250 mg, or 500 mg and most particularly 62.5 mg b.i.d., 125 mg.b.i.d., 250 mg b.i.d., or 500 mg b.i.d.

[0013] In one embodiment, the compound of the invention according to Formula (Ί) is provided for use in the treatment of cystic fibrosis caused by a CFTR class III mutation. In a particular embodiment, the class III mutation is selected from G551D, R553G, G1349D, S1251N, G178R, and S549N. In a more particular embodiment, the class III mutation is selected from G551D, and S 125 IN.

[0014] In a further aspect, the present invention provides pharmaceutical compositions for use in the treatment of cystic fibrosis comprising a compound of the invention, and a pharmaceutical carrier, excipient or diluent.

[0015] Moreover, the compounds of the invention, useful in the pharmaceutical compositions and treatment methods disclosed herein, are pharmaceutically acceptable as prepared and used.

[0016] In a further aspect of the invention, this invention provides a method of treating a mammal, in particular humans, afflicted with a condition selected from among those listed herein, and particularly cystic fibrosis, which method comprises administering an effective amount of the pharmaceutical composition or compounds of the invention as described herein.

[0017] In additional aspects, this invention provides methods for synthesizing the compounds of the invention, with representative synthetic protocols and pathways disclosed later on herein.

[0018] Other objects and advantages will become apparent to those skilled in the art from a consideration of the ensuing detailed description.

[0019] It will be appreciated that compounds of the invention may be metabolized to yield biologically active metabolites. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 shows Study 1 design.

[0021] Figure 2 shows Study 2 design.

[0022] Figure 3 shows the sweat chloride levels (mmol/L) in each patient in Study 2 at days 1, 8, 15, 22, 29 and at follow up visit.

[0023] Figure 4 shows the % change from baseline in ppFEVl in each patient in Study 2 at days 1, 8, 15, 22, 29 and at follow up visit.

[0024] Figure 5 shows the pre-dosing concentration of the compound according to Formula I (ng/mL) in Study 2 at days 1, 8, 15, 22 and 29.

[0025] Figure 6 shows the mean sweat chloride levels (mmol/L) in Study 1 at days 1, 8, 15, 22, 29, and at follow up visit.

[0026] Figure 7 shows the mean ppFEVl values (%) in Study 1 at days 1, 8, 15, 22, 29 (pre and 4h post dosing), and at follow up visit.

[0027] Figure 8 shows the mean pre-dosing concentration (ng/mL) of the compound according to Formula I (right axis) against the mean sweat chloride levels (mmol/L - left axis) in Study 1 at days 1, 8, 15, 22 and 29.

DETAILED DESCRIPTION OF THE INVENTION

Definitions

[0028] The following terms are intended to have the meanings presented therewith below and are useful in understanding the description and intended scope of the present invention.

[0029] When describing the invention, which may include compounds, pharmaceutical compositions containing such compounds and methods of using such compounds and compositions, the following terms, if present, have the following meanings unless otherwise indicated. It should also be understood that when described herein any of the moieties defined forth below may be substituted with a variety of substituents, and that the respective definitions are intended to include such substituted moieties within their scope as set out below. Unless otherwise stated, the term "substituted" is to be defined as set out below. It should be further understood that the terms "groups" and "radicals" can be considered interchangeable when used herein.

[0030] The articles 'a' and 'an' may be used herein to refer to one or to more than one (i.e. at least one) of the grammatical objects of the article. By way of example 'an analogue' means one analogue or more than one analogue.

[0031] 'Pharmaceutically acceptable' means approved or approvable by a regulatory agency of the Federal or a state government or the corresponding agency in countries other than the United States, or that is listed in the U.S. Pharmacopoeia or other generally recognized pharmacopoeia for use in animals, and more particularly, in humans.

[0032] 'Pharmaceutically acceptable salt' refers to a salt of a compound of the invention that is pharmaceutically acceptable and that possesses the desired pharmacological activity of the parent compound. In particular, such salts are non-toxic may be inorganic or organic acid addition salts and base addition salts. Specifically, such salts include: (1) acid addition salts, formed with inorganic acids such as hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid, phosphoric acid, and the like; or formed with organic acids such as acetic acid, propionic acid, hexanoic acid, cyclopentanepropionic acid, glycolic acid, pyruvic acid, lactic acid, malonic acid, succinic acid, malic acid, maleic acid, fumaric acid, tartaric acid, citric acid, benzoic acid, 3-(4-hydroxybenzoyl) benzoic acid, cinnamic acid, mandelic acid, methanesulfonic acid, ethanesulfonic acid, 1,2-ethane-disulfonic acid, 2-hydroxyethanesulfonic acid, benzenesulfonic acid, 4-chlorobenzenesulfonic acid, 2-naphthalenesulfonic acid, 4-toluenesulfonic acid, camphorsulfonic acid, 4-methylbicyclo[2.2.2]-oct-2-ene-l-carboxylic acid, glucoheptonic acid, 3-phenylpropionic acid, trimethylacetic acid, tertiary butylacetic acid, lauryl sulfuric acid, gluconic acid, glutamic acid, hydroxynaphthoic acid, salicylic acid, stearic acid, muconic acid, and the like; or (2) salts formed when an acidic proton present in the parent compound either is replaced by a metal ion, e.g. an alkali metal ion, an alkaline earth ion, or an aluminum ion; or coordinates with an organic base such as ethanolamine, diethanolamine, triethanolamine, N-methylglucamine and the like. Salts further include, by way of example only, sodium, potassium, calcium, magnesium, ammonium, tetraalkylammonium, and the like; and when the compound contains a basic functionality, salts of non-toxic organic or inorganic acids, such as hydrochloride, hydrobromide, tartrate, mesylate, acetate, maleate, oxalate and the like. The term 'pharmaceutically acceptable cation' refers to an acceptable cationic counter-ion of an acidic functional group. Such cations are exemplified by sodium, potassium, calcium, magnesium, ammonium, tetraalkylammonium cations, and the like.

[0033] 'LOCF' refers to Last-Observation-Carried-Forward imputation, which handles missing data by assigning the value recorded at the patient's last visit to all subsequent missed visits.

[0034] 'Pharmaceutically acceptable vehicle' refers to a diluent, adjuvant, excipient or carrier with which a compound of the invention is administered.

[0035] 'Prodrugs' refers to compounds, including derivatives of the compounds of the invention, which have cleavable groups and become by solvolysis or under physiological conditions the compounds of the invention which are pharmaceutically active in vivo. Such examples include, but are not limited to, choline ester derivatives and the like, N-alkylmorpholine esters and the like.

[0036] 'Solvate' refers to forms of the compound that are associated with a solvent, usually by a solvolysis reaction. This physical association includes hydrogen bonding. Conventional solvents include water, EtOH, acetic acid and the like. The compounds of the invention may be prepared e.g. in crystalline form and may be solvated or hydrated. Suitable solvates include pharmaceutically acceptable solvates, such as hydrates, and further include both stoichiometric solvates and non-stoichiometric solvates. In certain instances the solvate will be capable of isolation, for example when one or more solvent molecules are incorporated in the crystal lattice of the crystalline solid. 'Solvate' encompasses both solution-phase and isolable solvates. Representative solvates include hydrates, ethanolates and methanolates.

[0037] 'Subject' includes humans. The terms 'human', 'patient' and 'subject' are used interchangeably herein. [0038] 'Naive' subject(s) refers to subject(s) that have never received, or have not received treatment with one or more CFTR modulator for at least 2 weeks prior to screening.

[0039] 'Non-na^'ive' subject refers to subject(s) on a stable Ivacaftor regimen for at least 2 weeks prior to screening. ' on naive' subject receive a washout period for 1 week for Ivacaftor before start of the first treatment period.

[0040] The term 'CFTR modulator(s)' refers to modulator(s) of the CFTR protein. In particular, the term refers to CFTR potentiator(s), and/or CFTR corrector(s).

[0041] 'Effective amount' means the amount of a compound of the invention that, when administered to a subject for treating a disease, is sufficient to effect such treatment for the disease. The "effective amount" can vary depending on the compound, the disease and its severity, and the age, weight, etc., of the subject to be treated.

[0042] 'Preventing' or 'prevention' refers to a reduction in risk of acquiring or developing a disease or disorder (i.e. causing at least one of the clinical symptoms of the disease not to develop in a subject that may be exposed to a disease-causing agent, or predisposed to the disease in advance of disease onset.

[0043] The term 'prophylaxis' is related to 'prevention', and refers to a measure or procedure the purpose of which is to prevent, rather than to treat or cure a disease. Non-limiting examples of prophylactic measures may include the administration of vaccines; the administration of low molecular weight heparin to hospital patients at risk for thrombosis due, for example, to immobilization; and the administration of an anti-malarial agent such as chloroquine, in advance of a visit to a geographical region where malaria is endemic or the risk of contracting malaria is high.

[0044] 'Treating' or 'treatment' of any disease or disorder refers, in one embodiment, to ameliorating the disease or disorder (i.e. arresting the disease or reducing the manifestation, extent or severity of at least one of the clinical symptoms thereof). In another embodiment 'treating' or 'treatment' refers to ameliorating at least one physical parameter, which may not be discernible by the subject. In yet another embodiment, 'treating' or 'treatment' refers to modulating the disease or disorder, either physically, (e.g. stabilization of a discernible symptom), physiologically, (e.g. stabilization of a physical parameter), or both. In a further embodiment, "treating" or "treatment" relates to slowing the progression of the disease.

[0045] 'Compound(s) of the invention', and equivalent expressions, are meant to embrace compounds of the Formula(e) as herein described, which expression includes the pharmaceutically acceptable salts, and the solvates, e.g. hydrates, and the solvates of the pharmaceutically acceptable salts where the context so permits. Similarly, reference to intermediates, whether or not they themselves are claimed, is meant to embrace their salts, and solvates, where the context so permits.

[0046] As used herein, "Class I mutation(s)" refers to mutations which interfere with protein synthesis. They result in the introduction of a premature signal of termination of translation (stop codon) in the niRNA. The truncated CFTR proteins are unstable and rapidly degraded, so, the net effect is that there is no protein at the apical membrane. In particular, Class I mutation(s) refers to p.Gly542X (G542X), W1282X, c.489+lG>T (621+1 G>T), or c.579+lG>T (711+1G>T) mutation. More particularly, Class I mutation(s) refers to G542X; or W1282X mutations.

[0047] As used herein, "Class II mutation(s)" refers to mutations which affect protein maturation. These lead to the production of a CFTR protein that cannot be correctly folded and/or trafficked to its site of function on the apical membrane. In particular, Class II mutation(s) refers to p.Phe508del (F508del), p.Ile507del, or p.Asnl303Lys (N1303K) mutations. More particularly, Class II mutation(s) refers to F508del or N1303K mutations.

[0048] As used herein, "Class III mutation(s)" refers to mutations which alter the regulation of the CFTR channel. The mutated CFTR protein is properly trafficked and localized to the plasma membrane but cannot be activated, or it cannot function as a chloride channel. In particular, Class ΙΠ mutation(s) refers to p.Gly551Asp (G551D), G551S, R553G; G1349D; S 125 IN, G178R, S549N mutations. More particularly, Class III mutation(s) refers to G551D, R553G, G1349D, S 125 IN, G178R, or S549N mutations.

[0049] As used herein, "Class IV mutation(s)" refers to mutations which affect chloride conductance. The CFTR protein is correctly trafficked to the cell membrane but generates reduced CI- flow or a "gating defect" (most are missense mutations located within the membrane-spanning domain). In particular, Class IV mutation(s) refers to p.Argl 17His (Rl 17H), R347P, or p.Arg334Trp (R334W) mutations.

[0050] As used herein, "Class V mutation(s)" refers to mutations which reduce the level of normally functioning CFTR at the apical membrane or result in a "conductance defect" (for example partially aberrant splicing mutations or inefficient trafficking missense mutations). In particular, Class V mutation(s) refers to c.l210-12T[5] (5T allele), c.3140-26A>G (3272-26A>G), C.3850-2477OT (3849+lOkbOT) mutations.

[0051] As used herein, "Class VI mutation(s)" refers to mutations which decrease the stability of the CFTR which is present or which affect the regulation of other channels, resulting in inherent instability of the CFTR protein. In effect, although functional, the CFTR protein is unstable at the cell surface and it is rapidly removed and degraded by cell machinery. In particular, Class VI mutation(s) refers to Rescued F508del, 120del23, N287Y, 4326dellTC, or 4279insA mutations. More particularly, Class VI mutation(s) refers to Rescued F508del mutations.

[0052] 'Compound(s) of the invention', arid equivalent expressions, are meant to embrace compounds of the Formula(e) as herein described, which expression includes the pharmaceutically acceptable salts, and the solvates, e.g. hydrates, and the solvates of the pharmaceutically acceptable salts where the context so permits. Similarly, reference to intermediates, whether or not they themselves are claimed, is meant to embrace their salts, and solvates, where the context so permits.

[0053] When ranges are referred to herein, for example but without limitation, Ci-e alkyl, the citation of a range should be considered a representation of each member of said range.

[0054] Other derivatives of the compounds of this invention have activity in both their acid and acid derivative forms, but in the acid sensitive form often offers advantages of solubility, tissue compatibility, or delayed release in the mammalian organism (Bundgard, H, 1985). Prodrugs include acid derivatives are well known to practitioners of the art, such as, for example, esters prepared by reaction of the parent acid with a suitable alcohol, or amides prepared by reaction of the parent acid compound with a substituted or unsubstituted amine, or acid anhydrides, or mixed anhydrides. Simple aliphatic or aromatic esters, amides and anhydrides derived from acidic groups pendant on the compounds of this invention are particularly useful prodrugs. In some cases it is desirable to prepare double ester type prodrugs such as (acyloxy)alkyl esters or ((alkoxycarbonyl)oxy)alkylesters. Particular such prodrugs are the Ci-g alkyl, C2-8 alkenyl, C6-10 optionally substituted aryl, and (Ce-ιο aryl)-(Ci-4 alkyl) esters of the compounds of the invention.

[0055] As used herein, the term 'isotopic variant' refers to a compound that contains unnatural proportions of isotopes at one or more of the atoms that constitute such compound. For example, an 'isotopic variant' of a compound can contain one or more non-radioactive isotopes, such as for example, deuterium (²H or D), carbon-13 (^I3C), nitro (¹⁵N), or the like. It will be understood that, in a compound where such isotopic substitution is made, the following atoms, where present, may vary, so that for example, any hydrogen may be ²H/D, any carbon may be ¹³C, or any nitrogen may be ¹⁵N, and that the presence and placement of such atoms may be determined within the skill of the art. Likewise, the invention may include the preparation of isotopic variants with radioisotopes, in the instance for example, where the resulting compounds may be used for drug and/or substrate tissue distribution studies. The radioactive isotopes tritium, i.e. ³H, and carbon-14, i.e. ¹⁴C, are particularly useful for this purpose in view of their ease of incorporation and ready means of detection. Further, compounds may be prepared that are substituted with positron emitting isotopes, such as ⁿC, ¹⁸F, ¹⁵0 and ¹³N, and would be useful in Positron Emission Topography (PET) studies for examining substrate receptor occupancy.

[0056] It is also to be understood that compounds that have the same molecular formula but differ in the nature or sequence of bonding of their atoms or the arrangement of their atoms in space are termed 'isomers'. Isomers that differ in the arrangement of their atoms in space are termed 'stereoisomers'.

[0057] Stereoisomers that are not mirror images of one another are termed 'diastereomers' and those that are non-superimposable mirror images of each other are termed 'enantiomers'. When a compound has an asymmetric center, for example, it is bonded to four different groups, a pair of enantiomers is possible. An enantiomer can be characterized by the absolute configuration of its asymmetric center and is described by the R- and S-sequencing rules of Cahn and Prelog, or by the manner in which the molecule rotates the plane of polarized light and designated as dextrorotatory or levorotatory (i.e. as (+) or (-)- isomers respectively). A chiral compound can exist as either individual enantiomer or as a mixture thereof. A mixture containing equal proportions of the enantiomers is called a 'racemic mixture'.

[0058] All tautomeric forms of the compounds provided herein are intended to be encompassed within the scope of the invention. 'Tautomers' refer to compounds that are interchangeable forms of a particular compound structure, and that vary in the displacement of hydrogen atoms and electrons. Thus, two structures may be in equilibrium through the movement of π electrons and an atom (usually H). For example, enols and ketones are tautomers because they are rapidly interconverted by treatment with either acid or base. Another example of tautomerism is the aci- and nitro- forms of phenylnitromethane that are likewise formed by treatment with acid or base. Still another example of tautomerism is illustrated below:

[0059] Tautomeric forms may be relevant to the attainment of the optimal chemical reactivity and biological activity of a compound of interest.

THE INVENTION

[0060] The present invention provides the compound of the invention according to Formula I for use in the treatment of cystic fibrosis, in particular for use in the treatment of class III and/or IV mutations, and more particularly of class III mutations.

[0061] Accordingly, in a first aspect of the invention, the compound of the invention according to Formula (I) shown below:

[0062] In one embodiment, the compound of the invention according to Formula (I) is provided for use in the treatment of cystic fibrosis caused by a CFTR class III mutation. In a particular embodiment, the class ΙΠ mutation is selected from G551D, R553G, G1349D, S1251N, G178R, and S549N. In a more particular embodiment, the class III mutation is selected from G551D, and SI 25 IN.

[0063] In one embodiment, the compound of the invention is dosed as the sole treatment agent.

[0064] In another embodiment, the compound of the invention is dosed as the sole treatment agent in a naive subject.

[0065] In yet another embodiment, the compound of the invention is dosed as the sole treatment agent in a non-naive subject, wherein said non-naive subject is allowed to wash out from any previous treatment for at least 7 days. In a particular embodiment, the previous treatment is Ivacaftor.

[0066] In another embodiment, is provided the compound of the invention for use in the treatment of cystic fibrosis, wherein said compound of the invention is dosed orally over a period of at least 1 week, at least 2 weeks, at least 3 weeks, at least 4 weeks at a dose selected from 62.5 mg b.i.d., 125 mg.b.i.d.,

250 mg b.i.d., and 500 mg b.i.d. In a first particular embodiment, compound of the invention is dosed orally over a period of at least 2 weeks at a dose selected from 62.5 mg b.i.d., 125 mg.b.i.d., 250 mg b.i.d., and 500 mg b.i.d.. In a second particular embodiment, compound of the invention is dosed orally over a period of at least 4 weeks at a dose selected from 62.5 mg b.i.d., 125 mg.b.i.d., 250 mg b.i.d., and 500 mg b.i.d.. In a more particular embodiment, the cystic fibrosis is caused by a class III mutation. In a most particular embodiment, the cystic fibrosis is caused by a S 125 IN mutation. In another most particular embodiment, the cystic fibrosis is caused by a G551D mutation.

[0067] In another embodiment, is provided the compound of the invention for use in the treatment of cystic fibrosis in a naive subject, wherein said compound of the invention is dosed orally over a period of at least 1 week, at least 2 weeks, at least 3 weeks, or at least 4 weeks at a dose selected from 62.5 mg b.i.d., 125 mg.b.i.d., 250 mg b.i.d., and 500 mg b.i.d. In a first particular embodiment, compound of the invention is dosed orally over a period of at least 2 weeks at a dose selected from 62.5 mg b.i.d., 125 mg.b.i.d., 250 mg b.i.d., and 500 mg b.i.d.. In a second particular embodiment, compound of the invention is dosed orally over a period of at least 4 weeks at a dose selected from 62.5 mg b.i.d., 125 mg.b.i.d., 250 mg b.i.d., and 500 mg b.i.d. In a more particular embodiment, the cystic fibrosis is caused by a class ΙΠ mutation. In a most particular embodiment, the cystic fibrosis is caused by a S125 IN mutation. In another most particular embodiment, the cystic fibrosis is caused by a G551D mutation.

[0068] In another embodiment, is provided the compound of the invention for use in the treatment of cystic fibrosis in a non-naive subject, wherein said compound of the invention is dosed orally over a period of at least 1 week, at least 2 weeks, at least 3 weeks or at least 4 weeks at a dose selected from 62.5 mg b.i.d., 125 mg.b.i.d., 250 mg b.i.d., and 500 mg b.i.d, wherein no ppFEVl decrease is seen in at least 25% of the subjects. In a particular embodiment, a ppFEVl decrease of no more than 1%, no more than 2%, no more than 3%, no more than 4%, no more than 5%, no more than 6%, no more than 7%, no more than 8%, no more than 9%, or no more than 10% is seen compared to pre-dosing levels. In a first particular embodiment, compound of the invention is dosed orally over a period of at least 2 weeks at a dose selected from 62.5 mg b.i.d., 125 mg.b.i.d., 250 mg b.i.d., and 500 mg b.i.d.. In a second particular embodiment, compound of the invention is dosed orally over a period of at least 4 weeks at a dose selected from 62.5 mg b.i.d., 125 mg.b.i.d., 250 mg b.i.d., and 500 mg b.i.d. In a more particular embodiment, the cystic fibrosis is caused by a class III mutation. In a most particular embodiment, the cystic fibrosis is caused by a S 125 IN mutation. In another most particular embodiment, the cystic fibrosis is caused by a G55 ID mutation.

[0069] In another embodiment, is provided the compound of the invention for use in the treatment of cystic fibrosis in a non-naive subject, wherein said compound of the invention is dosed orally over a period of at least 1 week, at least 2 weeks, at least 3 weeks or at least 4 weeks at a dose selected from 62.5 mg b.i.d., 125 mg.b.i.d., 250 mg b.i.d., and 500 mg b.i.d, wherein no ppFEVl decrease is seen in at least 50% of the subjects. In a particular embodiment, a ppFEVl decrease of no more than 1%, no more than 2%, no more than 3%, no more than 4%, no more than 5%, no more than 6%, no more than 7%, no more than 8%, no more than 9%, or no more than 10% is seen compared to pre-dosing levels. In a first particular embodiment, compound of the invention is dosed orally over a period of at least 2 weeks at a dose selected from 62.5 mg b.i.d., 125 mg.b.i.d., 250 mg b.i.d., and 500 mg b.i.d.. In a second particular embodiment, compound of the invention is dosed orally over a period of at least 4 weeks at a dose selected from 62.5 mg b.i.d., 125 mg.b.i.d., 250 mg b.i.d., and 500 mg b.i.d. In a more particular embodiment, the cystic fibrosis is caused by a class III mutation. In a most particular embodiment, the cystic fibrosis is caused by a S 125 IN mutation. In another most particular embodiment, the cystic fibrosis is caused by a G55 ID mutation.

[0070] In another embodiment, is provided the compound of the invention for use in the treatment of cystic fibrosis in a non-na^'ive subject, wherein said compound of the invention is dosed orally over a period of at least 1 week, at least 2 weeks, at least 3 weeks or at least 4 weeks at a dose selected from 62.5 mg b.i.d., 125 mg.b.i.d., 250 mg b.i.d., and 500 mg b.i.d, wherein no ppFEVl decrease is seen in at least 75% of the subjects. In a particular embodiment, a ppFEVl decrease of no more than 1%, no more than 2%, no more than 3%, no more than 4%, no more than 5%, no more than 6%, no more than 7%, no more than 8%, no more than 9%, or no more than 10% is seen compared to pre-dosing levels. In a first particular embodiment, compound of the invention is dosed orally over a period of at least 2 weeks at a dose selected from 62.5 mg b.i.d., 125 mg.b.i.d., 250 mg b.i.d., and 500 mg b.i.d.. In a second particular embodiment, compound of the invention is dosed orally over a period of at least 4 weeks at a dose selected from 62.5 mg b.i.d., 125 mg.b.i.d., 250 mg b.i.d., and 500 mg b.i.d.. In a more particular embodiment, the cystic fibrosis is caused by a class III mutation. In a most particular embodiment, the cystic fibrosis is caused by a S 125 IN mutation. In another most particular embodiment, the cystic fibrosis is caused by a G55 ID mutation.

[0071] In another embodiment, is provided the compound of the invention for use in the treatment of cystic fibrosis in a naive subject, wherein said compound of the invention is dosed orally over a period of at least 1 week, at least 2 weeks, at least 3 weeks or at least 4 weeks at a dose selected from 62.5 mg b.i.d., 125 mg.b.i.d., 250 mg b.i.d., and 500 mg b.i.d, wherein a ppFEVl increase is seen in at least 25% of the subjects. In a particular embodiment, a ppFEVl increase of at least 1%, at least 2%, at least 3%, at least 4%, at least 5%, at least 6%, at least 7%, at least 8%, at least 9%, or at least 10% is seen compared to pre-dosing levels. In a particular embodiment, a ppFEVl increase of at least 1% is seen compared to pre- dosing levels. In another a particular embodiment, the cystic fibrosis is caused by a class ΠΙ mutation. In a more particular embodiment, the cystic fibrosis is caused by a SI 25 IN mutation. In another most particular embodiment, the cystic fibrosis is caused by a G551D mutation. In a first particular embodiment, compound of the invention is dosed orally over a period of at least 2 weeks at a dose selected from 62.5 mg b.i.d., 125 mg.b.i.d., 250 mg b.i.d., and 500 mg b.i.d.. In a second particular embodiment, compound of the invention is dosed orally over a period of at least 4 weeks at a dose selected from 62.5 mg b.i.d., 125 mg.b.i.d., 250 mg b.i.d., and 500 mg b.i.d.. In a more particular embodiment, the cystic fibrosis is caused by a class III mutation. In a most particular embodiment, the cystic fibrosis is caused by a S 125 IN mutation. In another most particular embodiment, the cystic fibrosis is caused by a G55 ID mutation. [0072] In another embodiment, is provided the compound of the invention for use in the treatment of cystic fibrosis in a naive subject, wherein said compound of the invention is dosed orally over a period of at least 1 week, at least 2 weeks, at least 3 weeks or at least 4 weeks at a dose selected from 62.5 mg b.i.d., 125 mg.b.i.d., 250 mg b.i.d., and 500 mg b.i.d, wherein a ppFEVl increase is seen in at least 50% of the subjects. In a particular embodiment, a ppFEVl increase of at least 1%, at least 2%, at least 3%, at least 4%, at least 5%, at least 6%, at least 7%, at least 8%, at least 9%, or at least 10% is seen compared to pre-dosing levels. In a particular embodiment, a ppFEVl increase of at least 1% is seen compared to pre- dosing levels. In another a particular embodiment, the cystic fibrosis is caused by a class III mutation. In a more particular embodiment, the cystic fibrosis is caused by a S 125 IN mutation. In another most particular embodiment, the cystic fibrosis is caused by a G551D mutation. In a first particular embodiment, compound of the invention is dosed orally over a period of at least 2 weeks at a dose selected from 62.5 mg b.i.d., 125 mg.b.i.d., 250 mg b.i.d., and 500 mg b.i.d.. In a second particular embodiment, compound of the invention is dosed orally over a period of at least 4 weeks at a dose selected from 62.5 mg b.i.d., 125 mg.b.i.d., 250 mg b.i.d., and 500 mg b.i.d.. In a more particular embodiment, the cystic fibrosis is caused by a class HI mutation. In a most particular embodiment, the cystic fibrosis is caused by a S 125 IN mutation. In another most particular embodiment, the cystic fibrosis is caused by a G55 ID mutation.

[0073] In another embodiment, is provided the compound of the invention for use in the treatment of cystic fibrosis in a naive subject, wherein said compound of the invention is dosed orally over a period of at least 1 week, at least 2 weeks, at least 3 weeks or at least 4 weeks at a dose selected from 62.5 mg b.i.d., 125 mg.b.i.d., 250 mg b.i.d., and 500 mg b.i.d, wherein a ppFEVl increase is seen in at least 75% of the subjects. In a particular embodiment, a ppFEVl increase of at least 1%, at least 2%, at least 3%, at least 4%, at least 5%, at least 6%, at least 7%, at least 8%, at least 9%, or at least 10% is seen compared to pre-dosing levels. In a particular embodiment, a ppFEVl increase of at least 1% is seen compared to pre- dosing levels. In another a particular embodiment, the cystic fibrosis is caused by a class III mutation. In a more particular embodiment, the cystic fibrosis is caused by a SI 25 IN mutation. In another most particular embodiment, the cystic fibrosis is caused by a G551D mutation. In a first particular embodiment, compound of the invention is dosed orally over a period of at least 2 weeks at a dose selected from 62.5 mg b.i.d., 125 mg.b.i.d., 250 mg b.i.d., and 500 mg b.i.d.. In a second particular embodiment, compound of the invention is dosed orally over a period of at least 4 weeks at a dose selected from 62.5 mg b.i.d., 125 mg.b.i.d., 250 mg b.i.d., and 500 mg b.i.d.. In a more particular embodiment, the cystic fibrosis is caused by a class III mutation. In a most particular embodiment, the cystic fibrosis is caused by a S 125 IN mutation. In another most particular embodiment, the cystic fibrosis is caused by a G551D mutation.

[0074] In another embodiment, is provided the compound of the invention for use in the treatment of cystic fibrosis in a non-naive subject, wherein said compound of the invention is dosed orally over a period of at least 2 weeks at a dose selected from 62.5 mg b.i.d., 125 mg.b.i.d., 250 mg b.i.d., and 500 mg b.i.d, wherein a ppFEVl decrease of no more than 1%, no more than 2%, no more than 3%, no more than 4%, no more than 5%, no more than 6%, no more than 7%, no more than 8%, no more than 9%, or no more than 10% is seen compared to pre-dosing levels. In a particular embodiment, a ppFEVl decrease of no more than 1%, no more than 2%, or no more than 3% is seen compared to pre-dosing levels. In another a particular embodiment, the cystic fibrosis is caused by a class III mutation. In a more particular embodiment, the cystic fibrosis is caused by a S 125 IN mutation. In another most particular embodiment, the cystic fibrosis is caused by a G55 ID mutation.

[0075] In another embodiment, is provided the compound of the invention for use in the treatment of cystic fibrosis in a non-naive subject, wherein said compound of the invention is dosed orally over a period of at least 4 weeks at a dose selected from 62.5 mg b.i.d., 125 mg.b.i.d., 250 mg b.i.d., and 500 mg b.i.d, wherein a ppFEVl decrease of no more than 1%, no more than 2%, no more than 3%, no more than 4%, no more than 5%, no more than 6%, no more than 7%, no more than 8%, no more than 9%, or no more than 10% is seen compared to pre-dosing levels. In a particular embodiment, a ppFEVl decrease of no more than 1%, no more than 2%, or no more than 3% is seen compared to pre-dosing levels. In another a particular embodiment, the cystic fibrosis is caused by a class III mutation. In a more particular embodiment, the cystic fibrosis is caused by a S 125 IN mutation. In another most particular embodiment, the cystic fibrosis is caused by a G55 ID mutation.

[0076] In another embodiment, is provided the compound of the invention for use in the treatment of cystic fibrosis in a naive subject, wherein said compound of the invention is dosed orally over a period of at least 2 weeks at a dose selected from 62.5 mg b.i.d., 125 mg.b.i.d., 250 mg b.i.d., and 500 mg b.i.d, wherein a ppFEVl increase of at least 1%, at least 2%, at least 3%, at least 4%, at least 5%, at least 6%, at least 7%, at least 8%, at least 9%, or at least 10% is seen compared to pre-dosing levels. In a particular embodiment, a ppFEVl increase of at least 1% is seen compared to pre-dosing levels. In another a particular embodiment, the cystic fibrosis is caused by a class III mutation. In a more particular embodiment, the cystic fibrosis is caused by a S 125 IN mutation. In another most particular embodiment, the cystic fibrosis is caused by a G551D mutation.

[0077] In another embodiment, is provided the compound of the invention for use in the treatment of cystic fibrosis in a naive subject, wherein said compound of the invention is dosed orally over a period of at least 4 weeks at a dose selected from 62.5 mg b.i.d., 125 mg.b.i.d., 250 mg b.i.d., and 500 mg b.i.d, wherein a ppFEVl increase of at least 1%, at least 2%, at least 3%, at least 4%, at least 5%, at least 6%, at least 7%, at least 8%, at least 9%, or at least 10% is seen compared to pre-dosing levels. In a particular embodiment, a ppFEVl increase of at least 1% is seen compared to pre-dosing levels. In another a particular embodiment, the cystic fibrosis is caused by a class III mutation. In a more particular embodiment, the cystic fibrosis is caused by a S 125 IN mutation. In another most particular embodiment, the cystic fibrosis is caused by a G55 ID mutation.

[0078] In one embodiment is provided the compound of the invention for use in the treatment of cystic fibrosis, wherein said compound of the invention is dosed orally over a period of 1 week at a dose of 125 mg.b.i.d, followed by 1 week at a dose of 250 mg b.i.d., followed by 2 weeks at a dose of 500 mg b.i.d, wherein a ppFEVl increase of at least 1%, at least 2%, at least 3%, at least 4%, at least 5%, at least 6%, at least 7%, at least 8%, at least 9%, at least 10%, or at least 15% is seen compared to pre-dosing levels. In a yet another particular embodiment, a ppFEVl increase of at least 1.2%, at least 1.4%, at least 1.6%, at least 1.8%,at least 2%, at least 2.2%, at least 2.4%, at least 2.6%, at least 2.8%, or at least 3% is seen compared to pre-dosing levels. In a yet another more particular embodiment, a ppFEVl increase of at least 1.2%, at least 1.4%, at least 1.6%, at least 1.8%, or at least 2% is seen compared to pre-dosing levels. In a more particular embodiment, the compound of the invention is dosed in a nai^'ve subject. In a further more particular embodiment, the compound of the invention is dosed in a non-na^'ive subject. In another a particular embodiment, the cystic fibrosis is caused by a class ΠΙ mutation. In a more particular embodiment, the cystic fibrosis is caused by a G551D mutation.

[0079] In another embodiment, is provided the compound of the invention for use in the treatment of cystic fibrosis, wherein said compound of the invention is dosed orally over a period of at least 1 week, at least 2 weeks, at least 3 weeks or at least 4 weeks at a dose selected from 62.5 mg b.i.d., 125 mg.b.i.d., 250 mg b.i.d., and 500 mg b.i.d, wherein a a sweat chloride decrease is seen in at least 25% of the subjects. In a more particular embodiment, the compound of the invention is dosed in a naive subject. In another a particular embodiment, the cystic fibrosis is caused by a class ΙΠ mutation. In a more particular embodiment, the cystic fibrosis is caused by a S 125 IN mutation. In another most particular embodiment, the cystic fibrosis is caused by a G551D mutation.

[0080] In another embodiment, is provided the compound of the invention for use in the treatment of cystic fibrosis, wherein said compound of the invention is dosed orally over a period of at least 1 week, at least 2 weeks, at least 3 weeks or at least 4 weeks at a dose selected from 62.5 mg b.i.d., 125 mg.b.i.d., 250 mg b.i.d., and 500 mg b.i.d, wherein a a sweat chloride decrease is seen in at least 50% of the subjects. In a more particular embodiment, the compound of the invention is dosed in a nai^'ve subject. In another a particular embodiment, the cystic fibrosis is caused by a class III mutation. In a more particular embodiment, the cystic fibrosis is caused by a SI 25 IN mutation. In another most particular embodiment, the cystic fibrosis is caused by a G551D mutation.

[0081] In another embodiment, is provided the compound of the invention for use in the treatment of cystic fibrosis, wherein said compound of the invention is dosed orally over a period of at least 1 week, at least 2 weeks, at least 3 weeks or at least 4 weeks at a dose selected from 62.5 mg b.i.d., 125 mg.b.i.d., 250 mg b.i.d., and 500 mg b.i.d, wherein a a sweat chloride decrease is seen in at least 75% of the subjects. In a more particular embodiment, the compound of the invention is dosed in a naive subject. In another a particular embodiment, the cystic fibrosis is caused by a class HI mutation. In a more particular embodiment, the cystic fibrosis is caused by a S 125 IN mutation. In another most particular embodiment, the cystic fibrosis is caused by a G55 ID mutation.

[0082] In another embodiment, is provided the compound of the invention for use in the treatment of cystic fibrosis, wherein said compound of the invention is dosed orally over a period of at least 2 weeks at a dose selected from 62.5 mg b.i.d., 125 mg.b.i.d., 250 mg b.i.d., and 500 mg b.i.d, wherein a sweat chloride decrease of at least 5 mmol/L, at least 10 mmol/L, at least 15 mmol/L, at least 20 mmol/L, at least 25 mmol/L, at least 30 mmol/L, at least 35 mmol/L, at least 40 mmol/L, at least 45 mmol/L, or at least 50 mmol/L, is seen compared to pre-dosing levels. In a particular embodiment, a sweat chloride decrease of at least 20 mmol L is seen compared to pre-dosing levels. In another particular embodiment, a sweat chloride decrease of at least 30 mmol/L is seen compared to pre-dosing levels. In yet another particular embodiment, a sweat chloride decrease of at least 40 mmol/L is seen compared to pre-dosing levels. In a more particular embodiment, the compound of the invention is dosed in a na^'ive subject. In a further more particular embodiment, the compound of the invention is dosed in a non-na^'ive subject. In another a particular embodiment, the cystic fibrosis is caused by a class III mutation. In a more particular embodiment, the cystic fibrosis is caused by a S 125 IN mutation. In another most particular embodiment, the cystic fibrosis is caused by a G55 ID mutation.

[0083] In another embodiment, is provided the compound of the invention for use in the treatment of cystic fibrosis, wherein said compound of the invention is dosed orally over a period of at least 4 weeks at a dose selected from 62.5 mg b.i.d., 125 mg.b.i.d., 250 mg b.i.d., and 500 mg b.i.d, wherein a sweat chloride decrease of at least 5 mmol/L, at least 10 mmol/L, at least 15 mmol/L, at least 20 mmol/L, at least 25 mmol/L, at least 30 mmol/L, at least 35 mmol/L, at least 40 mmol/L, at least 45 mmol/L, or at least 50 mmol L, is seen compared to pre-dosing levels. In a particular embodiment, a sweat chloride decrease of at least 20 mmol/L is seen compared to pre-dosing levels. In another particular embodiment, a sweat chloride decrease of at least 30 mmol/L is seen compared to pre-dosing levels. In yet another particular embodiment, a sweat chloride decrease of at least 40 mmol/L is seen compared to pre-dosing levels. In a more particular embodiment, the compound of the invention is dosed in a na^'ive subject. In a further more particular embodiment, the compound of the invention is dosed in a non-naive subject. In another a particular embodiment, the cystic fibrosis is caused by a class III mutation. In a more particular embodiment, the cystic fibrosis is caused by a S 125 IN mutation. In another most particular embodiment, the cystic fibrosis is caused by a G55 ID mutation.

[0084] In one embodiment is provided the compound of the invention for use in the treatment of cystic fibrosis, wherein said compound of the invention is dosed orally over a period of 1 week at a dose of 125 mg.b.i.d, followed by 1 week at a dose of 250 mg b.i.d., followed by 2 weeks at a dose of 500 mg b.i.d, wherein a sweat chloride decrease of at least 30 mmol/L, is seen compared to pre-dosing levels. In a more particular embodiment, the compound of the invention is dosed in a naive subject. In a further more particular embodiment, the compound of the invention is dosed in a non-na^'ive subject. In another a particular embodiment, the cystic fibrosis is caused by a class III mutation. In a more particular embodiment, the cystic fibrosis is caused by a G55 ID mutation.

[0085] In one embodiment is provided the compound of the invention for use in the treatment of cystic fibrosis, wherein said compound of the invention is dosed orally over a period of 1 week at a dose of 125 mg.b.i.d, followed by 1 week at a dose of 250 mg b.i.d., followed by 2 weeks at a dose of 500 mg b.i.d, wherein a sweat chloride decrease of at least 49 mmol/L, is seen compared to pre-dosing levels. In a more particular embodiment, the compound of the invention is dosed in a naive subject. In another a particular embodiment, the cystic fibrosis is caused by a class III mutation. In a more particular embodiment, the cystic fibrosis is caused by a G55 ID mutation. [0086] In one embodiment is provided the compound of the invention for use in the tre atment of cystic fibrosis, wherein said compound is dosed orally at a dose sufficient to reach in vivo exposures of at least 80 ng/mL, at least 100 ng/mL, at least 120 ng/niL, at least 140 ng/mL, at least 160 ng/mL, at least 180 ng/mL, or least 200 ng/mL. In a particular embodiment, compound is dosed orally at a dose sufficient to reach in vivo exposures of at least 80 ng/mL, at least 90 ng/mL, or at least 100 ng/mL. In a more particular embodiment, the compound in dosed at 500 mg b.i.d. In a most particular embodiment, the compound is dosed at 500 mg b.i.d. for at least one week. In a further most particular embodiment, the compound is dosed at 500 mg b.i.d. for at least two weeks.

[0087] In one embodiment is provided the compound of the invention for use in the tre atment of cystic fibrosis caused by a G551D mutation, wherein said compound is dosed orally at a dose sufficient to reach in vivo exposures of at least 80 ng/mL, at least 100 ng/mL, at least 120 ng/mL, at least 140 ng/mL, at least 160 ng/mL, at least 180 ng/mL, or least 200 ng/mL. In a particular embodiment, compound is dosed orally at a dose sufficient to reach in vivo exposures of at least 80 ng/mL, at least 90 ng/mL, or at least 100 ng/mL. In a more particular embodiment, the compound in dosed at 500 mg b.i.d. In a most particular embodiment, the compound is dosed at 500 mg b.i.d. for at least one week. In a further most particular embodiment, the compound is dosed at 500 mg b.i.d. for at least two weeks.

[0088] In one embodiment is provided the compound of the invention for use in the tre atment of cystic fibrosis, wherein said compound is dosed orally at a dose sufficient to reach in vivo exposures corresponding to at least EC50, at least ECeo, at least EC70, at least ECso, or at least EC90. In a particular embodiment, the compound is dosed orally at a dose sufficient to reach in vivo exposures corresponding to at least EC70, at least ECso,. or at least EC90. In a more particular embodiment, the compound is dosed at a dose of 500 mg b.i.d.. In a most particular embodiment, the compound is dosed at a dose of 500 mg b.i.d. for at least 1 week. In a most particular embodiment, the compound is dosed at a dose of 500 mg b.i.d. for at least 2 weeks.

[0089] In one embodiment is provided the compound of the invention for use in the tre atment of cystic fibrosis caused by a G55 ID mutation, wherein said compound is dosed orally at a dose sufficient to reach in vivo exposures corresponding to at least EC50, at least EC60, at least EC70, at least ECso, or at least EC90. In a particular embodiment, the compound is dosed orally at a dose sufficient to reach in vivo exposures corresponding to at least EC70, at least ECeo.-or at least EC90. In a more particular embodiment, the compound is dosed at a dose of 500 mg b.i.d.. In a most particular embodiment, the compound is dosed at a dose of 500 mg b.i.d. for at least 1 week. In a most particular embodiment, the compound is dosed at a dose of 500 mg b.i.d. for at least 2 weeks.

[0090] The present invention also provides methods for the production of these compounds, pharmaceutical compositions comprising these compounds and methods for the prophylaxis and/or treatment of cystic fibrosis by administering the compounds of the invention.

[0091] In one embodiment the compound of the invention is not an isotopic variant.

[0092] In one aspect the compound of the invention according to any one of the embodiments herein described is present as the free base. [0093] In one aspect the compound of the invention according to any one of the embodiments herein described is a pharmaceutically acceptable salt.

[0094] In one aspect the compound of the invention according to any one of the embodiments herein described is a solvate of the compound.

[0095] In one aspect the compound of the invention according to any one of the embodiments herein described is a solvate of a pharmaceutically acceptable salt of a compound.

[0096] In certain aspects, the present invention provides prodrugs and derivatives of the compounds according to the formulae above. Prodrugs are derivatives of the compounds of the invention, which have metabolically cleavable groups and become by solvolysis or under physiological conditions the compounds of the invention, which are pharmaceutically active, in vivo. Such examples include, but are not limited to, choline ester derivatives and the like, N-alkylmorpholine esters and the like.

[0097] Other derivatives of the compounds of this invention have activity in both their acid and acid derivative forms, but the acid sensitive form often offers advantages of solubility, tissue compatibility, or delayed release in the mammalian organism (Bundgard, H, 1985). Prodrugs include acid derivatives well known to practitioners of the art, such as, for example, esters prepared by reaction of the parent acid with a suitable alcohol, or amides prepared by reaction of the parent acid compound with a substituted or unsubstituted amine, or acid anhydrides, or mixed anhydrides. Simple aliphatic or aromatic esters, amides and anhydrides derived from acidic groups pendant on the compounds of this invention are preferred prodrugs, i some cases it is desirable to prepare double ester type prodrugs such as (acyloxy)alkyl esters or ((alkoxycarbonyl)oxy)alkylesters. Particularly useful are the Ci to Cs alkyl, C2-C8 alkenyl, aryl, C7-C12 substituted aryl, and C7-C12 arylalkyl esters of the compounds of the invention.

PHARMACEUTICAL COMPOSITIONS

[0098] When employed as a pharmaceutical, a compound of the invention is typically administered in the form of a pharmaceutical composition. Such compositions can be prepared in a manner well known in the pharmaceutical art and comprise at least one active compound of the invention according to Formula I. Generally, a compound of the invention is administered in a pharmaceutically effective amount. The amount of compound of the invention actually administered will typically be determined by a physician, in the light of the relevant circumstances, including the condition to be treated, the chosen route of administration, the actual compound of the invention administered, the age, weight, and response of the individual patient, the severity of the patient's symptoms, and the like.

[0099] The pharmaceutical compositions of this invention can be administered by a variety of routes including oral, rectal, transdermal, subcutaneous, intra-articular, intravenous, intramuscular, and intranasal. Depending on the intended route of delivery, a compound of the invention is preferably formulated as either injectable or oral compositions or as salves, as lotions or as patches all for transdermal administration.

[0100] The compositions for oral administration can take the form of bulk liquid solutions or suspensions, or bulk powders. More commonly, however, the compositions are presented in unit dosage forms to facilitate accurate dosing. The term 'unit dosage forms' refers to physically discrete units suitable as unitary dosages for human subjects and other mammals, each unit containing a predetermined quantity of active material calculated to produce the desired therapeutic effect, in association with a suitable pharmaceutical excipient, vehicle or carrier. Typical unit dosage forms include prefilled, premeasured ampules or syringes of the liquid compositions or pills, tablets, capsules or the like in the case of solid compositions. In such compositions, the compound of the invention according to Formula I is usually a minor component (from about 0.1 to about 50% by weight or preferably from about 1 to about 40% by weight) with the remainder being various vehicles or carriers and processing aids helpful for forming the desired dosing form.

[0101] Liquid forms suitable for oral administration may include a suitable aqueous or non-aqueous vehicle with buffers, suspending and dispensing agents, colorants, flavors and the like. Solid forms may include, for example, any of the following ingredients, or compound of the inventions of a similar nature: a binder such as microcrystalline cellulose, gum tragacanth or gelatin; an excipient such as starch or lactose, a disintegrating agent such as alginic acid, Primogel, or corn starch; a lubricant such as magnesium stearate; a glidant such as colloidal silicon dioxide; a sweetening agent such as sucrose or saccharin; or a flavoring agent such as peppermint or orange flavoring.

[0102] Injectable compositions are typically based upon injectable sterile saline or phosphate-buffered saline or other injectable carriers known in the art. As before, the active compound of the invention according to Formula I in such compositions is typically a minor component, often being from about 0.05 to 10% by weight with the remainder being the injectable carrier and the like.

[0103] Transdermal compositions are typically formulated as a topical ointment or cream containing the active ingredient(s), generally in an amount ranging from about 0.01 to about 20% by weight, preferably from about 0.1 to about 20% by weight, preferably from about 0.1 to about 10% by weight, and more preferably from about 0.5 to about 15% by weight. When formulated as an ointment, the active ingredients will typically be combined with either a paraffmic or a water-miscible ointment base. Alternatively, the active ingredients may be formulated in a cream with, for example an oil-in-water cream base. Such transdermal formulations are well-known in the art and generally include additional ingredients to enhance the dermal penetration of stability of the active ingredients or the formulation. All such known transdermal formulations and ingredients are included within the scope of this invention.

[0104] A compound of the invention can also be administered by a transdermal device. Accordingly, transdermal administration can be accomplished using a patch either of the reservoir or porous membrane type, or of a solid matrix variety.

[0105] The above-described components for orally administrable, injectable or topically administrable compositions are merely representative. Other materials as well as processing techniques and the like are set forth in Part 8 of Remington's Pharmaceutical Sciences, 17^th edition, 1985, Mack Publishing Company, Easton, Pennsylvania, which is incorporated herein by reference. [0106] A compound of the invention can also be administered in sustained release forms or from sustained release drug delivery systems. A description of representative sustained release materials can be found in Remington's Pharmaceutical Sciences.

[0107] The following formulation examples illustrate representative pharmaceutical compositions that may be prepared in accordance with this invention. The present invention, however, is not limited to the following pharmaceutical compositions.

Formulation 1 - Tablets

[0108] A compound of the invention according to Formula I may be admixed as a dry powder with a dry gelatin binder in an approximate 1 :2 weight ratio. A minor amount of magnesium stearate may be added as a lubricant. The mixture may be formed into 240-270 mg tablets (80-90 mg of active compound of the invention according to Formula I per tablet) in a tablet press.

Formulation 2 - Capsules

[0109] A compound of the invention according to Formula I may be admixed as a dry powder with a starch diluent in an approximate 1 : 1 weight ratio. The mixture may be filled into 250 mg capsules (125 mg of active compound of the invention according to Formula I per capsule).

Formulation 3 - Liquid

[0110] A compound of the invention according to Formula I (125 mg), may be admixed with sucrose (1.75 g) and xanthan gum (4 mg) and the resultant mixture may be blended, passed through a No. 10 mesh U.S. sieve, and then mixed with a previously made solution of microcrystalline cellulose and sodium carboxymethyl cellulose (11 :89, 50 mg) in water. Sodium benzoate (10 mg), flavor, and color may be diluted with water and added with stirring. Sufficient water may then be added with stirring. Further sufficient water may be then added to produce a total volume of 5 mL.

Formulation 4 - Tablets

[0111] A compound of the invention according to Formula I may be admixed as a dry powder with a dry gelatin binder in an approximate 1 :2 weight ratio. A minor amount of magnesium stearate may be added as a lubricant. The mixture may be formed into 450-900 mg tablets (150-300 mg of active compound of the invention according to Formula I) in a tablet press.

Formulation 5 - Injection

[0112] A compound of the invention according to Formula I may be dissolved or suspended in a buffered sterile saline injectable aqueous medium to a concentration of approximately 5 mg/mL.

Formulation 6 - Topical

[0113] Stearyl alcohol (250 g) and a white petrolatum (250 g) may be melted at about 75°C and then a mixture of A compound of the invention according to Formula I (50 g) methylparaben (0.25 g), propylparaben (0.15 g), sodium lauryl sulfate (10 g), and propylene glycol (120 g) dissolved in water (about 370 g) may be added and the resulting mixture may be stirred until it congeals. BIOLOGICAL EXAMPLES

[0114] The compound of the invention according to Formula I has been extensively profiled and data are disclosed in WO 2015/018823.

Example 1. Clinical setting

1.1. Study 1 - Cystic fibrosis patients with G551D mutation

[0115] This study is an open label, multi-center, ascending-dose study to evaluate two oral doses of the compound according to Formula I in subjects with CF and the G55 ID mutation.

[0116] Male and female subjects with a confirmed diagnosis of CF and > 18 years of age are screened to determine eligibility according to the inclusion and exclusion criteria.

[0117] Written informed consent will be obtained from subjects before any study-related procedures and/or assessments are performed. CF patients with the G551D mutation may or may not have been treated with Ivacaftor, an approved CFTR potentiator. The study will include subjects treated with Ivacaftor who are on a stable dose regimen for at least 2 weeks, as well as those who are na^'fve to Ivacaftor or did not use Ivacaftor for at least 2 weeks prior to screening. Ivacaftor is not allowed as a concomitant medication during the washout or treatment periods of the study. All subjects on a stable Ivacaftor regimen for at least 2 weeks prior to screening will have a washout period for I week before start of the first treatment period. Subjects who are naive to Ivacaftor or who have not received Ivacaftor for at least 2 weeks at screening will not require a washout.

[0118] The length of the entire treatment for each subject will be 4 weeks and will consist of 3 consecutive treatment periods: two 1-week periods followed by one 2-week period, without washout between the treatment periods. Sufficient subjects will be screened as to include at least 12 subjects to receive three different dosages administered during the three consecutive treatment periods. The following doses are tested: 125 mg b.i.d., 250 mg b.i.d., and 500 mg b.i.d.

[0119] The compound according to Formula I is administered b.i.d. as oral tablet under fed conditions. After the last study drug administration, there will be a 7-10 days follow-up period. Subjects may (re-) start Ivacaftor treatment following a 4-day wash-out period after the last study drug intake, at the investigator's discretion.

[0120] Subjects are in the study for the total duration of up to maximum 9 weeks (screening to follow-up visit). The end of the study is defined as the last contact with the last subject.

1.1.1. Sample size

[0121] Sufficient subjects are screened as to include at least 12 subjects in the study.

Table I. Study 1 patient baseline demographics

Subject # Prior Ivacaftor treatment SwCl (mmol L) ppFEVl CFTR Genotype

1 Yes 95 91 F508DEL / G551D

2 Yes 113 96 F508DEL / G551D Subject # Prior Ivacaftor treatment SwCl (mmolL) ppFEVl CFTR Genotype

3 Yes 102 92 G551D/R553X

4 No 79 88 G551D/711+3A>G

5 Yes 85 92 F508DEL/G551D

6 Yes 95 82 F508DEL/G551D

7 Yes 63 104 G551D/711+3A>G

8 Yes 96 80 V520F/G551D

9 Yes 105 75 F508DEL/G551D

10 Yes 95 67 F508DEL/G551D

11 Yes 108 77 F508DEL/G551D

12 Yes 101 43 F508DEL/G551D

13 Yes 104 50 F508DEL/G551D

14 Yes 112 77 G551D/E60X

15 Yes 95 56 G542X/G551D

16 Yes 97 73 F508DEL/G551D

17 Yes 109 61 F508DEL/G551D

18 Yes 69 52 G551D/E585X

19 Yes 98 30 F508DEL/G551D

20 Yes 97 42 F508DEL/G551D

21 Yes 110 46 F508DEL/G551D

22 Yes 99 37 G551D/G1123

23 Yes 98 44 F508DEL/G551D

24 Yes 105 78 F508DEL/G551D

25 Yes 116 98 F508DEL/G551D

26 Yes 92 NA F508DEL/G551D

NA: Not applicable

1.1.2. Study duration

The study comprises 3 consecutive periods of 7 days wherein the patient receives a 125 mg b.i.d. dose regimen, 7 days wherein the patient receives a 250 mg b.i.d. dose regimen, followed by a 14 days 500 mg b.i.d. dose regimen.

1.1.3. Participants

1.1.3.1. Inclusion Criteria

[0122] Subjects who meet all of the following criteria are eligible for the study:

Male or female subjects > 18 years of age, on the day of signing the Informed Consent Form (ICF), with a confirmed diagnosis of cystic fibrosis:

o Clinical diagnosis of cystic fibrosis with signs/symptoms involving at least two organ systems, and o Medical history of elevated sweat chloride >60 mmol/L by quantitative pilocarpine iontophoresis

(documented in the subject's medical record) or 2 disease causing CFTR mutations (documented in the subject's medical record).

Gating G551D CFTR mutation on at least one allele in the CFTR gene (documented in the subject's medical record or CF registry); any known or unknown mutation allowed on the 2nd allele. Subject inclusion can be performed, provided that genotype information is available in source data.

Subject must meet one of the following: o Subjects currently receiving treatment with Ivacaftor must be on a stable regimen for at least 2 weeks prior to screening

or

o Subjects not on a treatment regimen with Ivacaftor for at least 2 weeks prior to screening

- Weight > 40.0 kg.

Subjects on stable concomitant treatment regimen for at least 4 weeks prior to baseline (excluding Ivacaftor).

Pre- or post-bronchodilator ppFEVl > 40% of predicted normal for age, gender, height at screening. Female subjects must have a negative blood pregnancy test. Determination of serum follicle- stimulating hormone (FSH) will be done for any suspected postmenopausal female with at least 12-months of continuous spontaneous amenorrhea, with FSH levels > 40 lU/mL being confirmative for menopause. For hysterectomy and tubal ligation, documented confirmation will be requested. Subjects will have to use highly effective contraceptive methods prior to the first dose of the study drug, during the study, and for at least 12 weeks after the last dose of the study drug,

o If the subject is a sexually active woman of childbearing potential, she and her male partner are required to simultaneously use 2 effective contraceptive methods. Hormonal contraceptives will not be considered as an effective method; however, female subjects are not required to discontinue hormonal contraceptives. Female subjects who use contraception must have done so for at least 14 days prior to the first dose of the study drug,

o Non-vasectomized sexually active male subjects with female partners of childbearing potential must be willing to use a condom in addition to having their female partner use another form of contraception.

Understand and comply with protocol specific requirements and instructions.

Able and willing to give voluntary written informed consent and meet all of the inclusion criteria and none of the exclusion criteria before being enrolled in the study. The subjects must sign the informed consent form prior to any study-related procedures and agree to the schedule of assessments.

1.1.3.2. Exclusion criteria

[0123] Subjects meeting one or more of the following criteria cannot be selected for this study:

History of sensitivity to any component of the study drug, or a history of drug or other allergy that, in the investigator's opinion, contraindicates the subject's participation in the study.

On an Ivacaftor-containing treatment regimen and unable or unwilling to discontinue Ivacaftor for the washout and treatment periods of the study.

Concomitant use of antifungal drugs (e.g. itraconazole, ketoconazole, voriconazole, posaconazole) within 4 weeks of baseline.

A history of a clinically meaningful unstable or uncontrolled chronic disease including underlying cystic fibrosis that makes the subject unsuitable for inclusion in the study in the opinion of the investigator. Liver cirrhosis and portal hypertension.

History of malignancy within the past 5 years (except for carcinoma in situ of the uterine cervix and basal cell carcinoma of the skin that has been treated with no evidence of recurrence).

Any significant change in the medical regimen (including dose and frequency) for pulmonary health within 4 weeks of baseline, including: antibiotics; corticosteroids (see Section 4.3.8.3); inhaled bronchodilators, hypertonic saline, mannitol or dornase alfa; ibuprofen and airway clearance techniques. Individuals taking inhaled antibiotics for suppression of chronic airways infection must be on a stable regimen for at least 8 weeks prior to baseline and willing to continue the same antibiotic through Day 29 (see Section 4.3.8 for individuals who cycle inhaled antibiotics).

Unstable pulmonary status or respiratory tract infection (including pulmonary exacerbation), based on the investigator's opinion, or changes in therapy for pulmonary disease within 4 weeks of baseline. History of lung volume reduction surgery or lung transplant.

Use of continuous (24 h per day) supplemental oxygen therapy.

Clinically significant abnormalities detected on electrocardiogram (ECG) regarding either rhythm or conduction (e.g., QTcF > 450 ms, or a known long QT syndrome). A first degree heart block will not be considered as a significant abnormality.

Use of medication known to prolong the QT interval (including herbal and naturopathic therapy). Pregnant or breast-feeding women.

History of solid organ or hematological transplantation or currently on a transplantation waiting list. Abnormal liver function defined as aspartate aminotransferase (AST), alanine aminotransferase (ALT), GGT > 3 x upper limit of the normal range or bilirubin > 2 x upper limit of the normal range. Abnormal renal function defined as creatinine clearance < 50ml/min using the Cockroft-Gault equation.

History of alcohol or illicit drug abuse within I year prior to screening, as deemed by the investigator. Participation in another experimental therapy study within 30 days or 5 times the half-life of the experimental therapy, whichever is longer, prior to screening for this study or current enrollment in any other study (involvement in an ongoing observational study is allowed.

Smoking or use of tobacco products within three months prior to baseline

1.1.4. Treatment

[0124] The following doses are evaluated:

125 mg b.i.d.: 1 tablet of 125 mg in the morning and 1 tablet of 125 mg in the evening,

250 mg b.i.d.: 1 tablet of 250 mg in the morning and 1 tablet of 250 mg in the evening, and

500 mg b.i.d.: 1 tablet of 500 mg in the morning and 1 tablet of 500 mg in the evening.

[0125] Oral tablets are administered b.i.d. for 3 consecutive treatment periods (1 week 125 mg b.i.d.,

1 week 250 mg b.i.d., and 2 weeks 500 mg b.i.d.).

[0126] During the visits on Day 1, Day 8, Day 15 and Day 22, subjects will be provided with a supply of study drug to take home. [0127] Subjects will take study drug twice daily at home, except on the days when a visit to the clinic is scheduled (Days 1, 8, 15, 22 and 29) where the morning dose will be taken during the visit at the clinic.

[0128] The interval between two subsequent study drug administrations must be at least 6 h.

[0129] Study drug administration will begin on the morning of Day 1 (at the clinic) and will end on the morning (at home) of the Day 29 visit, as follows:

Treatment period 1: first dose on Day 1 in the morning at the clinic and last dose on Day 7 in the evening at home,

Treatment period 2: first dose on Day 8 in the morning at the clinic and last dose on Day 1 in the evening at home,

Treatment period 3: first dose on Day 15 in the morning at the clinic and last dose on Day 29 in the morning at the clinic.

[0130] A 1-day deviation window is allowed for study visits scheduled after Day 1. In case the 1-day deviation is applied for the visit on Day 8 or Day 15, the dose switch must take place on the visit day, i.e., Day 9 or Day 16, respectively.

[0131] Study medication is to be taken in fed condition with a meal or snack. Subjects will be instructed to take the study drug after consuming a fat-containing meal (breakfast or evening meal). Meals and snacks recommended in CF guidelines or meals recommended in standard nutritional guidelines contain adequate amounts of fat. Examples of meals that contain fat are those prepared with butter or oils, or those containing eggs, peanut butter, whole-milk dairy products (such as whole milk, cheese, and yogurt), nuts or meats.

[0132] On visit days, when the morning dose of study drug will be administered at the clinic after pre-dose assessments have been completed, a fat-containing breakfast (or fat-containing snack) will be provided by the site before the morning dose of study drug. On the morning of Day 29 (PK profile), the breakfast must start 30 minutes before study drug administration and will have to be consumed in 20 minutes.

[0133] Oral tablets should be taken orally with 240 ml of water. Subjects will be instructed to swallow the study drug whole, and not chew the drug prior to swallowing.

[0134] Subjects will be instructed to record study drug intake (from Day 1 through Day 29) in the diary.

[0135] If a subject misses a dose (e.g., because he/she forgot to take the medication), he/she must take immediately the missed dose with food within 6 h after the planned intake time. If the study drug is not taken within 6 h after the planned time, the missed dose must be skipped. During each visit, the investigator will record a summary of the study drug intake data in the eCRF.

[0136] Individual dose reductions will not be allowed.

1.1.5. Concomitant therapy

[0137] Concomitant therapies taken for the long-term treatment of preexisting conditions can continue during the study provided they are in accordance with the inclusion and exclusion criteria. It is required that the medication regimens be stable prior to study entry and continued without variation of dose or regimen during the study.

[0138] All concomitant therapies are to be recorded on the relevant eCRF page(s), along with the reason for and details of therapy use. All prior surgeries will be recorded on the relevant eCRF page(s).

1.1.5.1. Concomitant stable CF treatment regimen

[0139] All medications in relation to the treatment of CF must be used during the study in accordance with the inclusion and exclusion criteria.

[0140] Subjects must remain on a stable medication regimen (including dose and frequency) for pulmonary health within 4 weeks of the baseline visit and for the entire study duration (i.e., through the follow-up visit). Subjects who take inhaled antibiotics for suppression of chronic airways infection must be on a stable regimen for at least 8 weeks prior to baseline. Influenza vaccination cannot be administered within 4 weeks of baseline and for the entire study duration.

[0141] Examples of stable medication regimen for pulmonary health are: antibiotics, corticosteroids, inhaled bronchodilators, hypertonic saline, mannitol or dornase alfa; ibuprofen and airway clearance techniques.

Subjects can be on stable treatment with chronic use of corticosteroids provided that the daily dose of prednisone (or equivalent) is lower than 10 mg.

Subjects who are using chronically inhaled antibiotics must remain on the same regimen for the duration of the study;

Subjects who are on cycling inhaled antibiotics (including 'on/off cycling), must continue on the same schedule. The timing of the first dose of study drug must be as close as possible to the first day of the inhaled cycling antibiotic in the cycle. This also applies to subjects who are cycling two different alternate inhaled antibiotics each month.

[0142] If the subject shows a worsening of his/her CF disease condition, which in the investigator's opinion needs an alternative treatment approach, treatment with study drug will be discontinued and the subject will be withdrawn from the study, after discussion between the investigator and the sponsor medical monitor.

1.1.5.2. Ivacaftor-containing CF treatment regimen

[0143] Ivacaftor is not allowed as a concomitant medication during the washout or treatment periods of the study. Subjects on a stable ivacaftor-containing treatment regimen for at least 2 weeks prior to screening will have a 1-week ivacaftor washout period before start of the first treatment period. Any missed ivacaftor dose in the 5 days prior to washout must be documented in the subject's diary. Upon qualification for the study, subjects will be contacted by telephone to confirm that ivacaftor treatment can be stopped. Subjects will be instructed to document the timing of the last ivacaftor intake in the study diary. [0144] Subjects are allowed to (re-)start ivacaftor treatment after study drug treatment, at the investigator's discretion. There will be a 4-day wash-out period of the test compound after the last study drug intake (morning dose on Day 29) to avoid interactions between the study drug and ivacaftor.

1.1.6. Study assessment

The sequence of study assessments at one study visit will be as follows (when applicable):

1. Diary review

2. Physical examination, 12-lead ECG, vital signs (i.e. oral body temperature, blood pressure, supine HR, respiratory rate) when assessed pre-dose

3. Blood sampling for PK / safety laboratory analysis

4. Sweat sample collection (other assessments in parallel with sweat sample collection are

not allowed)

5. Spirometry

6. Physical examination, 12-lead ECG, vital signs when assessed post-dose

7. Pulse oximetry

[0145] On Days 1, 8, 15, 22 and 29, assessments of sweat chloride, spirometry and PK will be performed pre-morning dose (no PK assessment is performed on day 1).

[0146] In addition, the following study assessments will be performed at pre- and post-morning dose time points:

On Day 1 and Day 29,vital signs (blood pressure, supine HR, oral body temperature and respiratory rate) will be measured at 2 occasions: pre-morning dose and post-morning dose around t_max (4±1 h post-dose). On Days 8, 15 and 22, vital signs will be measured pre-morning dose only.

On Day 29, spirometry will be measured at 2 occasions: pre-morning dose and post-moming dose around t_max (4±1 hrs post-dose).

On Day 29 (PK profile), pre-morning dose and post-moming dose blood samples will be taken for PK assessment.

1.2. Study 2 - Cystic fibrosis patients with SI 25 IN mutation Study design

[0147] This study is an open label, multi-center, ascending-dose study to evaluate two oral doses of the compound according to Formula I in subjects with CF and the SI 25 IN mutation.

[0148] Male and female subjects with a confirmed diagnosis of CF and > 18 years of age are screened to determine eligibility according to the inclusion and exclusion criteria.

[0149] Written informed consent will be obtained from subjects before any study-related procedures and/or assessments are performed. CF patients with the S 125 IN mutation may or may not have been treated with ivacaftor, an approved CFTR potentiator. The study will include subjects treated with ivacaftor who are on a stable dose regimen for at least 2 weeks, as well as those who are na^'ive to ivacaftor or did not use ivacaftor for at least 2 weeks prior to screening. Ivacaftor is not allowed as a concomitant medication during the washout or treatment periods of the study. All subjects on a stable ivacaftor regimen for at least 2 weeks prior to screening will have a washout period for I week before staft of the first treatment period. Subjects who are naii^'e to ivacaftor or who have not received ivacaftor for at least 2 weeks at screening will not require a washout.

[0150] The length of the entire treatment for each subject will be 4 weeks and will consist of 2 consecutive treatment periods of two weeks each, without washout between the treatment periods. Sufficient subjects will be screened as to include at least 6 subjects in the study to receive two different dosages administered during the two consecutive treatment periods (see figure below). The following GLPG1837 doses will be tested: 62.5 mg b.i.d 125 mg b.i.d.

[0151] The compound of invention will be administered b.i.d. as oral tablet under fed conditions. After the last study drug administration, there will be a 7-10 days follow-up period. Subjects may (re-)start ivacaftor treatment following a 4-day wash-out period after the last study drug intake, at the investigator's discretion.

[0152] Each subject will be in the study for the total duration of up to maximum 9 weeks (screening to follow-up visit). The end of the study is defined as the last contact with the last subject.

1.2.2. Sample size

[0153] Sufficient subjects are screened as to include at least 6 subjects in the study.

Table Π. Study 2 patient baseline demographics

1.2.3. Study duration

The study comprises 2 consecutive periods of 14 days wherein the patient receives a 62.5 mg b.i.d. dose regimen, followed by a 14 days 125 mg b.i.d. dose regimen.

1.2.4. Participants

1.2.4.1. Inclusion Criteria

[0154] Subjects who meet all of the following criteria are eligible for the study:

(documented in the subject's medical record) or 2 disease causing CFTR mutations (documented in the subject's medical record). Gating S 125 IN CFTR mutation on at least one allele in the CFTR gene (documented in the subject's medical record or CF registry); any known or unknown mutation allowed on the 2nd allele. Subject inclusion can be performed, provided that genotype information is available in source data.

Subject must meet one of the following:

o Subjects currently receiving treatment with ivacaftor must be on a stable regimen for at least 2 weeks prior to screening

Or

Weight > 40.0 kg.

Pre- or post-bronchodilator ppFEVl > 40% of predicted normal for age, gender, height at screening. Female subjects must have a negative blood pregnancy test. Determination of serum follicle- stimulating hormone (FSH) will be done for any suspected postmenopausal female with at least 12-months of continuous spontaneous amenorrhea, with FSH levels > 40 IU/mL being confirmative for menopause. For hysterectomy and tubal ligation, documented confirmation will be requested. Subjects will have to use highly effective contraceptive methods prior to the first dose of the study drug, during the study, and for at least 12 weeks after the last dose of the study drug,

o If the subject is a sexually active woman of childbearing potential, she and her male partner are required to simultaneously use 2 effective contraceptive methods of the protocol. Hormonal contraceptives will not be considered as an effective method; however, female subjects are not required to discontinue hormonal contraceptives. Female subjects who use contraception must have done so for at least 14 days prior to the first dose of the study drug,

Understand and comply with protocol specific requirements and instructions.

1.2.4.2. Exclusion criteria

5] Subjects meeting one or more of the following criteria cannot be selected for this study:

On an ivacaftor-containing treatment regimen and unable or unwilling to discontinue ivacaftor for the washout and treatment periods of the study. Concomitant use of antifungal drugs (e.g. itraconazole, ketoconazole, voriconazole, posaconazole) within 4 weeks of baseline.

A history of a clinically meaningful unstable or uncontrolled chronic disease including underlying cystic fibrosis that makes the subject unsuitable for inclusion in the study in the opinion of the investigator.

Liver cirrhosis and portal hypertension.

Any significant change in the medical regimen (including dose and frequency) for pulmonary health within 4 weeks of baseline, including: antibiotics; corticosteroids; inhaled bronchodilators, hypertonic saline, mannitol or dornase alfa; ibuprofen and airway clearance techniques. Individuals taking inhaled antibiotics for suppression of chronic airways infection must be on a stable regimen for at least 8 weeks prior to baseline and willing to continue the same antibiotic through Day 29. Unstable pulmonary status or respiratory tract infection (including pulmonary exacerbation), based on the investigator's opinion, or changes in therapy for pulmonary disease within 4 weeks of baseline. History of lung volume reduction surgery or lung transplant.

Use of continuous (24 h per day) supplemental oxygen therapy.

Smoking or use of tobacco products within three months prior to baseline

1.2.5. Treatment

[0156] Subjects are not allowed to significantly change within 4 weeks prior to baseline and throughout the entire study duration, their medical regimen (including dose and frequency) for pulmonary health, excluding ivacaftor.

[0157] The following doses are evaluated: 62.5 mg b.i.d.: 1 tablet of 62.5 mg in the morning and 1 tablet of 62.5 mg in the evening

125 mg b.i.d.: 1 tablet of 125 mg in the morning and 1 tablet of 125 mg in the evening

[0158] Oral tablets are administered b.i.d. for 2 consecutive treatment periods (14 days each).

[0159] During the visits on Day 1, Day 8, Day 15 and Day 22, subjects will be provided with a supply of study drug to take home.

[0160] Subjects will take study drug twice daily at home, except on the days when a visit to the clinic is scheduled (Days 1, 8, 15, 22 and 29) where the morning dose will be taken during the visit at the clinic.

[0161] The interval between two subsequent study drug administrations must be at least 6 h.

[0162] Study drug administration will begin on the morning of Day 1 (at the clinic) and will end on the morning (at home) of the Day 29 visit, as follows:

Treatment period 1 : first dose on Day 1 in the morning at the clinic and last dose on Day 14 in the evening at home,

Treatment period 2: first dose on Day 15 in the morning at the clinic and last dose on Day 29 in the morning at the clinic.

[0163] A 1-day deviation window is allowed for study visits scheduled after Day 1. In case the 1-day deviation is applied for the visit on Day 15, the dose switch must take place on the visit day, i.e., Day 14 or Day 16.

[0164] Study medication is to be taken in fed condition with a meal or snack. Subjects will be instructed to take the study drug after consuming a fat-containing meal (breakfast or evening meal). Meals and snacks recommended in CF guidelines or meals recommended in standard nutritional guidelines contain adequate amounts of fat. Examples of meals that contain fat are those prepared with butter or oils, or those containing eggs, peanut butter, whole-milk dairy products (such as whole milk, cheese, and yogurt), nuts or meats.

[0165] On visit days, when the morning dose of study drug will be administered at the clinic after pre-dose assessments have been completed, a fat-containing breakfast (or fat-containing snack) will be provided by the site before the morning dose of study drug.

[0166] Oral tablets should be taken orally with 240 mL of water. Subjects will be instructed to swallow the study drug whole, and not chew the drug prior to swallowing.

[0167] Subjects will be instructed to record study drug intake (from Day 1 through Day 29) in the diary.

[0168] If a subject misses a dose (e.g., because he/she forgot to take the medication), he/she must take immediately the missed dose with food within 6 h after the planned intake time. If the study drug is not taken within 6 h after the planned time, the missed dose must be skipped. During each visit, the investigator will record a summary of the study drug intake data in the eCRF.

[0169] Individual dose reductions will not be allowed.

1.2.6. Study assessment

1. Diary review 2. Physical examination, 12-lead ECG, vital signs (i.e. oral body temperature, blood pressure, supine HR, respiratory rate) when assessed pre-dose

3. Blood sampling for P / safety laboratory analysis

not allowed)

5. Spirometry

6. Physical examination, 12-lead ECG, vital signs when assessed post-dose

7. Pulse oximetry

[0170] On Days 1, 8, 15, 22 and 29, assessments of sweat chloride, spirometry and PK will be performed pre-moming dose.

[0171] In addition, the following study assessments will be performed at pre- and post-morning dose time points:

On Day 1 and Day 29,vital signs (blood pressure, supine HR, oral body temperature and respiratory rate) will be measured at 2 occasions: pre-moraing dose and post-morning dose around t_max (4+1 h post-dose). On Days 8, 15 and 22, vital signs will be measured pre-morning dose only.

On Day 29, spirometry will be measured at 2 occasions: pre-morning dose and post-morning dose around t_max (4+1 hrs post-dose).

On Day 29, one pre-morning dose blood sample and one post-morning dose blood sample (around tmax, i.e., 4+1 hrs post-dose) will be taken for PK assessment.

1.3. Biological protocols

1.3.1. Sweat chloride concentration

1.3.1.1. Protocol

[0172] Sweat chloride concentration is a biomarker of CF disease that is useful for testing activity of compounds targeted at restoring CFTR activity.

[0173] Sweat chloride concentrations are used to measure CFTR function in the sweat gland and are determined by an approved collection device (Macroduct system) according to the approved 2009 guideline issued by the Clinical and Laboratory Standards Institute (CLSI, Sweat testing: sample collection and quantitative chloride analysis; approved guideline - third edition. CLSI document C34-A3. Wayne, PA: Clinical and Laboratory Standards Institute, 2009).

[0174] Sweat samples will be taken at days 1, 8, 15, 22 and 29, and sent to a central laboratory for analysis and interpretation of results. It is not allowed to perform other assessments in parallel with sweat sample collection.

[0175] To ensure consistency and reproducibility in this multi-centered study, sweat secretions will be collected at each site according to standardized operating procedures. Two sweat collections, one from each arm will be obtained from each subject at each time point. Sweat samples will be immediately frozen and sent to a central laboratory. Details of sweat sample handling, shipment instructions, determination of sweat chloride concentration and analyses will be provided in a separate laboratory manual. The chloride value obtained from the collection with the greater amount of sweat at each time point will be used for analysis.

1.3.1.2. Results.

[0176] Using the protocol above the following data are obtained.

Table ΠΙ. Study 1 sweat chloride data (mmol/L) mean LOCF

NA: not applicable

Table IV. Study 2 sweat chloride data (mmol/L)

ND= not determined

1.3.2. Pulmonary Function by Spirometry

1.3.2.1. Protocol

[0177] Spirometry will be performed to assess pulmonary function at days 1, 8, 15, 22 and 29. Spirometry can be performed pre-bronchodilator or post-bronchodilator at screening but should take place prior to bronchodilator use at all other visits.

[0178] The spirometry test must meet the criteria for acceptability and repeatability as defined in the ATS/ERS guidelines (Miller et al., 2005) and performed according to ECFS-CTN (European Cystic Fibrosis Society Clinical Trials Network) standard operating procedures (ECFS-CTN, European Cystic Fibrosis Society Clinical Trial Network Standardization Committee. Standard Operating Procedure: Spirometry > 6 years. V1.0, 11 June 2012, 2012).

[0179] During study visits on Days 1, 8, 15 and 22, spirometry is performed before the morning dose. On Day 29, the spirometry test is to be performed prior to the morning dose of study drug and an additional spirometry must be performed after the study drug intake around t_max (4+1 h post-dose). [0180] The screening spirometry to determine the subject's eligibility should preferably be performed pre-bronchodilator. In case the subject used his/her dose of bronchodilator before the screening visit, screening spirometry is allowed to be performed post-bronchodilator.

[0181] The screening spirometry to determine the subject's eligibility should be performed pre-bronchodilator. In case the subject did not withhold his/her dose of bronchodilator, screening spirometry is allowed to be performed post-bronchodilator.

[0182] Spirometry on study visits Day 1 through Day 29 should be performed pre-bronchodilator.

If on Day 1, the subject forgets to withhold his/her dose of bronchodilator then all subsequent spirometry should be collected post-bronchodilator, to be consistent with the conditions during the baseline measurement.

If on Day 1 spirometry is collected pre-bronchodilator, but then at a subsequent visit the subject forgets to withhold his/her dose of bronchodilator, then spirometry should be collected post- bronchodilator for that visit only.

[0183] Pre-bronchodilator spirometry is defined as spirometry testing performed for a subject who has:

Withheld their short-acting β-agonist (e.g., albuterol) or anticholinergic (e.g., ipratropium bromide) more than 4 h prior to the spirometry assessment

and

Withheld their long acting bronchodilator like salmeterol or formoterol at least 12 h, or longer-acting agents like indacaterol and tiotropium at least 24 h prior to the spirometry assessment.

1.3.2.2. Spirometry parameters and calculation of predicted values

[0184] The following parameters are measured as part of the spirometry assessment:

FEV1 (L) and percent predicted FEV1 (ppFEVl) for age, gender, and height

Forced Vital Capacity (FVC) (L) and percent predicted FVC (ppFEVl) for age, gender, and height

- FEV1/FVC ratio

Forced expiratory flow between 25 and 75% of exhaled volume (FEF25-75)

[0185] Predicted values will be estimated using the 2012 Global Lungs Initiative (GLI) equation

(Quanjer et al., 2012).

1.3.2.3. Results

[0186] Using the protocol above, the following results are obtained.

Table V. Study 1 - ppFEVl values (%)

Subject Screening Baseline Day Day Day Day Day 29 - 4h Follow up n# (day -7) (day 1) 8 15 22 29 post dosing (day 36)

1 94 91 90 92 ND ND 87 ND

2 101 96 98 100 94 94 ND 91

3 93 92 90 87 89 93 90 90

4 89 88 87 91 89 92 90 90

5 84 92 89 90 84 84 95 91

6 102 82 85 97 106 94 93 93

7 102 104 104 101 101 96 97 100

8 81 80 82 77 75 74 75 ND Subject Screening Baseline Day Day Day Day Day 29 - 4h Follow up n# (day -7) (day 1) 8 15 22 29 post dosing (day 36)

9 91 75 67 63 77 85 86 82

10 80 67 72 67 67 71 76 68

11 80 77 74 76 81 76 73 70

12 45 43 46 44 ND ND ND ND

13 51 50 50 ND 50 50 ND ND

14 81 77 74 76 80 82 83 79

15 66 56 57 58 64 66 63 67

16 86 73 73 72 72 68 76 75

17 64 61 59 59 63 59 58 ND

18 56 52 50 51 49 53 51 48

19 42 30 29 31 35 35 35 33

20 48 42 42 43 43 45 47 43

21 52 46 51 51 ND 47 ND 58

22 45 37 40 40 38 34 ND ND

23 49 44 50 51 50 54 56 53

24 75 78 74 80 81 77 81 80

25 105 98 98 98 110 104 104 103

26 60 ND 60 62 66 57 62 60 mean 73.92 69.24 68.88 70.28 72.34 70.41 75.14 73.70

Table VI. Change from baseline of ppFEVl Study 1 (%) using LOCF imputation

NA: Not applicable

ND: Not determined Table VII. Change from baseline of ppFEVl Study 2 (%)

NA: Not applicable

1.4. Cellular assay

[0187] Electrophysiological measurements on primary human bronchial epithelial cell cultures are a useful preclinical surrogate of clinical efficacy (Rowe, S.M., Verkman, A.S., 2013. Cystic Fibrosis Transmembrane Regulator Correctors and Potentiators. Cold Spring Harb. Perspect. Med. 3, a009761. doi: 10.1101/cshperspect.a009761), therefore compounds are evaluated in an Ussing chamber and/or TECC assay which are electrophysiological measurement assays.

1.4.1. Ussing chambers assay

1.4.1.1. Protocol

[0188] The Ussing chambers assay measures the functionality of the cystic fibrosis Transmembrane Conductance regulator (CFTR) by measuring the short circuit current (I_sc) generated over the basolateral and apical membrane of lung epithelial cells.

[0189] In order to measure the J_sc, the epithelium is short circuited by injecting a current that is adjusted by a feed-back amplifier to keep the transepithelial potential (V_† ) at 0 mV. The amount of current required is adjusted by a feedback circuit and continuously measured. Intermittently the voltage is clamped to values different from 0 mV thus enabling an estimate of the transepithelial resistance (R_t ).

[0190] For this purpose, bronchial epithelial cells isolated from CF patients heterozygous for CFTR G551D and AF508 mutations (University of Chapel Hill, North Carolina) are plated on type TV collagen- coated Snapwell™ supports (Corning-Costar). Human airway epithelia are generated by provision of an air-liquid interface for 21 days to form well-differentiated polarized cultures that resemble in vivo pseudo-stratified ciliated epithelium (Fulcher, M.L., Gabriel, S., Burns, K.A., Yankaskas, J.R., Randell, S.H., 2005. Well-differentiated human airway epithelial cell cultures. Methods Mol. Med. 107, 183-206).

[0191] For electrophysiological recording, the human airway epithelia are mounted in Ussing chambers for measurement of short-circuit current (7_SC). The epithelia are bathed in a NaCl-Ringer solution (120 mM NaCl, 25 mM NaHCOa, 1.2 mM CaCl₂, 1.2 mM MgCb, 0.8 mM KH₂P0₄, 0.8 mM K₂HP0₄, pH 7.4, 5 mM glucose) on the basolateral side and a glutamate-ringer solution (120 mM sodium glutamate, 25 mM NaHCOs, 1.2 mM CaCl₂, 1.2 mM MgCl₂, 0.8 mM KH₂P0₄, 0.8 mM K₂HP0₄, pH 7.4, 5 mM glucose) on the apical side to generate a CI^" gradient. Both chambers are gassed with 95% 0₂, 5% CO2, and maintained at 27 °C. Apical amiloride is used to inhibit the endogenous ENaC currents while forkolin is applied on both apical and basolateral side to stimulate CFTR. After forskolin triggering, compounds are added on both side to test their potential for increasing CFTR gating. The increase in I_§Q is used as a measure for the increased CFTR activity, EC50 values can be generated by measuring impact of different concentrations of compound on Short circuit current on primary cells, for this purpose the same Snapwell™ is used for the addition of increasing amounts of compound and the increase in I_sc signal at each step is then transformed into a dose response curve. Inh-172, an inhibitor specific for CFTR, is used to test the specificity of the tested compounds.

1.4.2. TECC assay

1.4.2.1. Primary bronchial epithelial cells Protocol

[0192] The TECC (Tranepithelial Clamp Circuit, EP-design) assay measures the functionality of the cystic fibrosis Transmembrane Conductance regulator (CFTR) by measuring the short circuit current (7_SC) generated over the basolateral and apical membrane of lung epithelial cells. In TECC the transepithelial potential PD and transepithelial resistance (R_T ) are measured in an open circuit and transformed to I_SC using Ohm's law. 24 Wells can be measured simultaneously allowing a higher throughput compared to Ussing chambers. This assay measures the effective concentration inducing a response of xx% compared to the maximal effect observed (EC_XX).

[0193] For this purpose, differentiated bronchial epithelial cells isolated from heterozygous G551D/AF508 CF patients are plated on type T collagen-coated Transwell^® supports (Costar). Human airway epithelia are generated by provision of an air-liquid interface for 21 days to form well- differentiated polarized cultures that resemble in vivo pseudo-stratified ciliated epithelium (Fulcher, M.L., Gabriel, S., Burns, K.A., Yankaskas, J.R., Randell, S.H., 2005. Well-differentiated human airway epithelial cell cultures. Methods Mol. Med. 107, 183-206).

[0194] On G551D/AF508 CFTR heterozygous samples compounds are added in an acute mode to the differentiated cells.

[0195] For the acute mode, for electrophysiological recording, the human airway epithelia are mounted in the TECC heating plate for electrophysiological measurement and kept at 37 °C. The epithelia are bathed in a NaCl-Ringer solution (120 mM NaCl, 25 mM NaHC0₃,1.2 mM CaCl₂, 1.2 mM MgCl₂, 0.8 mM KH₂PO4, 0.8 mM K2HPO4, pH 7.4, 5 mM glucose) on both the basolateral and apical sides. Apical amiloride is used to inhibit the endogenous ENaC currents while forkolin is applied on both apical and basolateral side to stimulate CFTR. After forskolin triggering, compounds are added on both sides to test their potential for increasing CFTR gating. Measurements are done during a 20 min timeframe with recordings every 2 min. The increase in 7_SC is used as a measure for the increased CFTR activity, EC_XX values for example (EC50, ΕΟβο, EC70, etc ..) can be generated by measuring impact of different concentrations of compound on I_sc on primary cells, for this purpose each transwell is treated with a different compound concentration. Inh-172, an inhibitor specific for CFTR, is used to test the specificity of the tested compounds.

[0196] Similar TECC recordings are performed using primary cells for other channel gating defective or channel conductance defective CFTR mutants such as SI 25 IN to determine effect of compound on channel activity.

[0197] For example, using this assay, an EC₅o of 373 nM for G551D and 41.5 nM for S1251N was measured for the compound according to Formula I.

Example 2. Pharmacokinetics (PK)

[0198] PK assessments will be measured using liquid chromatography with tandem mass spectrometry (LC-MS/MS) method, and are performed at SGS Life Science Services, 1300 Wavre, Belgium.

[0199] Further tests (e.g., stability studies) might be performed on stored remaining plasma samples, and additional metabolites might be determined if deemed appropriate.

2.1. Study 1 Protocol

[0200] In the first, second and third treatment periods, one blood sample (1 mL) will be collected by venipuncture in all subjects before the morning dose during the visit on Days 8, 15 and 22, and at the ED visit (if applicable). The exact date and time of blood collection will be recorded in the eCRF, as well as the exact date and time of last preceding study drug intake.

[0201] In the third treatment period, blood samples (1 mL) will be collected in all subjects by venipuncture (or indwelling catheter inserted prior to the vital signs and ECG measurements) on Day 29 at pre-dose and 0.5, 1, 2, 3, 5 and 8 h post morning dose.

[0202] In case a subject is not available for PK profile sampling on Day 29, the PK sampling is allowed any day from Day 23 to Day 28, at the subject's convenience, while keeping one premorning dose PK sample and safety and efficacy assessments during the visit on Day 29.

[0203] For subjects who have permanent intravenous access, it is allowed to use this catheter for PK blood sampling. Blood will be collected into vacuum tubes containing EDTA (2 mL BD Vacutainer whole blood tubes with K2EDTA additive) and will be immediately chilled (ice bath). Plasma samples are stored at -80°C until shipment to the central laboratory.

2.1. Study 2 Protocol

[0204] PK assessments are measured using liquid chromatography with tandem mass spectrometry (LC- MS/i\4S) method, and will be performed by the bioanalytical laboratory in charge of these analyses (SGS Life Science Services, 1300 Wavre, Belgium).

[0205] Further tests (e.g., stability studies, enzyme induction) might be performed on stored remaining plasma samples, and additional metabolites might be determined if deemed appropriate.

[0206] On Day 1, Day 8, Day 15, and Day 22, one pre-morning dose blood sample (1 mL) is collected in all subjects by venipuncture. On Day 29 a blood sample is taken pre-morning dose and another post-dose blood sample is collected around t_max (4±1 h post-morning dose). The exact date and time of blood collection are recorded in the eCRF, as well as the exact date and time of last preceding study drug intake.

[0207] For subjects who have permanent intravenous access, it is allowed to use this catheter for PK blood sampling. Blood will be collected into vacuum tubes containing EDTA (2 mL BD Vacutainer whole blood tubes with K2EDTA additive) and are immediately chilled (ice bath). Plasma samples is then stored at -80'C until shipment to the central laboratory.

2.2. Pharmacokinetic Parameters

[0208] Pharmacokinetic calculations are performed by SGS-LSS using SAS (version 9.2 or higher) and/or Phoenix WinNonLin 6.2 or higher (Pharsight Corporation, Palo Alto, CA, USA).

[0209] In the third treatment period (Day 29), the following plasma PK parameters, where appropriate, will be calculated using non compartmental analysis from individual plasma concentration-time profiles: Cmax maximum observed plasma concentration tmax the time of occurrence of Cmax AUC0-12h area under the plasma concentration-time curve from time zero to 12 h after dosing, calculated by the linear up - logarithmic down trapezoidal rule C12h trough plasma concentration (just before the next dosing i.e. pre-dose sample)

[0210] Metabolite over parent ratios (R) are calculated as well as dose normalized parameters (Cmax/dose, C12h/dose, AUC0-12h/dose).

[0211] Additional PK parameters may be calculated as appropriate.

2.2.1. Statistical methods

[0212] All statistical calculations will be performed by SGS LSS using the SAS (version 9.2 or higher) and/or Phoenix WinNonlin (version 6.2 or higher) software for statistical computations and for graphical purposes. All statistical methods shall be detailed in a statistical analysis plan that will be finalized prior to the database lock. All data collected in this study will be documented using summary tables, figures, and subject data listings.

2.3. Results

[0213] Using the protocols above, the following results are obtained.

Table VTH. Serum concentration of the compound according to Formula I pre-dosing in Study 1 (ng/mL).

Table IX. Serum concentration of the compound according to Formula I pre-dosing in Study 2 (ng/mL).

NA: Not Applicable

* the value appears to be aberrant and has not been included in the graph

FINAL REMARKS

[0214] It will be appreciated by those skilled in the art that the foregoing descriptions are exemplary and explanatory in nature, and intended to illustrate the invention and its preferred embodiments. Through routine experimentation, an artisan will recognize apparent modifications and variations that may be made without departing from the spirit of the invention. All such modifications coming within the scope of the appended claims are intended to be included therein. Thus, the invention is intended to be defined not by the above description, but by the following claims and their equivalents.

[0215] All publications, including but not limited to patents and patent applications, cited in this specification are herein incorporated by reference as if each individual publication are specifically and individually indicated to be incorporated by reference herein as though fully set forth. [0216] It should be understood that factors such as the differential cell penetration capacity of the various compounds can contribute to discrepancies between the activity of the compounds in the in vitro biochemical and cellular assays.

[0217] At least some of the chemical names of compound of the invention as given and set forth in this application, may have been generated on an automated basis by use of a commercially available chemical naming software program, and have not been independently verified. Representative programs performing this function include the Lexichem naming tool sold by Open Eye Software, Inc. and the Autonom Software tool sold by MDL, Inc. In the instance where the indicated chemical name and the depicted structure differ, the depicted structure will control.

REFERENCES

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Dekkers, J.F., Wiegerinck, C.L., de Jonge, H.R., Bronsveld, I., Janssens, H.M., de Winter-de Groot, K.M., Brandsma, A.M., de Jong, N.W.M., Bijvelds, M.J.C., Scholte, B.J., Nieuwenhuis, E.E.S., van den Brink, S., Clevers, H., van der Ent, C.K., Middendorp, S., Beekman, J.M., 2013. A functional CFTR assay using primary cystic fibrosis intestinal organoids. Nat. Med. 19, 939-945. doi: 10.1038/nm.3201

Kerem, B., Rommens, J.M., Buchanan, J.A., Markiewicz, D., Cox, T.K., Chakravarti, A., Buchwald, M., Tsui, L.C., 1989. Identification of the cystic fibrosis gene: genetic analysis. Science 245, 1073- 1080.

Lubamba, B., Dhooghe, B., Noel, S., Leal, T., 2012. Cystic fibrosis: insight into CFTR pathophysiology and pharmacotherapy. Clin. Biochem. 45, 1 132-1144. doi:10.1016/j.clinbiochem.2012.05.034

MacKenzie, T., Gifford, A.H., Sabadosa, K.A., Quinton, H.B., Knapp, E.A., Goss, C.H., Marshall, B.C., 2014. Longevity of Patients With Cystic Fibrosis in 2000 to 2010 and Beyond: Survival Analysis of the Cystic Fibrosis Foundation Patient Registry. Ann. Intern. Med. 161 , 233-241. doi:10.7326/M13-0636

Miller, M.R., Hankinson, J., Brusasco, V., Burgos, F., Casaburi, R., Coates, A., Crapo, R., Enright, P., van der Grinten, C.P.M., Gustafsson, P., Jensen, R., Johnson, D.C., Maclntyre, N., McKay, R., Navajas, D., Pedersen, O.F., Pellegrino, R., Viegi, G., Wanger, J., ATS/ERS Task Force, 2005. Standardisation of spirometry. Eur. Respir. J. 26, 319-338. doi:10.1 183/09031936.05.00034805

Okiyoneda, T., Veit, G., Dekkers, J.F., Bagdany, M., Soya, N., Xu, H., Roldan, A., Verkman, A.S., Kurth, M., Simon, A., Hegedus, T., Beekman, J.M., Lukacs, G.L., 2013. Mechanism-based corrector combination restores AF508-CFTR folding and function. Nat. Chem. Biol. 9. doi: 10.1038/nchembio.1253

O'Sullivan, B.P., Freedman, S.D, 2009. Cystic fibrosis. The Lancet 373, 1891-1904. doi: 10.1016/S0140- 6736(09)60327-5

Pittman, J.E., Ferkol, T.W., 2015. The Evolution of Cystic Fibrosis Care. Chest 148, 533-542. doi:10.1378/chest. l4-1997

Quanjer, P.H., Stanojevic, S., Cole, T.J., Baur, X., Hall, G.L., Culver, B.H., Enright, P.L., Hankinson,

J.L., Ip, M.S.M., Zheng, J., Stocks, J., 2012. Multi-ethnic reference values for spirometry for the

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Organoids From Human Colon, Adenoma, Adenocarcinoma, and Barrett's Epithelium.

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Claims

1. A compound according to Formula I:

or a pharmaceutically acceptable salt thereof, or a solvate or the salt of a solvate thereof, or an active metabolite thereof for use in the treatment of cystic fibrosis wherein the compound of the invention is dosed orally at a dose of 62.5 mg b.i.d., 125 mg.b.i.d., 250 mg b.i.d., or 500 mg b.i.d.

2. The compound or a pharmaceutically acceptable salt thereof, or a solvate or the salt of a solvate thereof, or an active metabolite thereof for use according to claim 1, wherein the cystic fibrosis mutation is selected from Class ΠΙ and/or Class IV mutation.

3. The compound or a pharmaceutically acceptable salt thereof, or a solvate or the salt of a solvate thereof, or an active metabolite thereof for use according to claim 1, wherein the cystic fibrosis mutation is a Class III mutation.

4. The compound or a pharmaceutically acceptable salt thereof, or a solvate or the salt of a solvate thereof, or an active metabolite thereof for use according to claim 3, wherein the Class III mutation is selected from G551D, and S1251N.

5. The compound or a pharmaceutically acceptable salt thereof, or a solvate or the salt of a solvate thereof, or an active metabolite thereof for use according to any one of claims 1-4, wherein the compound is dosed as the sole treatment agent.

6. The compound or a pharmaceutically acceptable salt thereof, or a solvate or the salt of a solvate thereof, or an active metabolite thereof for use according to any one of claims 1-5, wherein the compound is dosed in a na^'ive subject.

7. The compound or a pharmaceutically acceptable salt thereof, or a solvate or the salt of a solvate thereof, or an active metabolite thereof for use according to any one of claims 1-5, wherein the compound is dosed in a non-naive subject, wherein said non-naive subject is allowed to wash out from any previous treatment for at least 7 days.

8. The compound or a pharmaceutically acceptable salt thereof, or a solvate or the salt of a solvate thereof, or an active metabolite thereof for use according to any one of claims 1-7, wherein the compound is dosed orally over a period of at least 1 week, at least 2 weeks, at least 3 weeks, or at least 4 weeks at a dose selected from 62.5 mg b.i.d., 125 mg.b.i.d., 250 mg b.i.d., and 500 mg b.i.d..

9. The compound or a pharmaceutically acceptable salt thereof, or a solvate or the salt of a solvate thereof, or an active metabolite thereof for use according to any one of claims 1-5, wherein the compound is dosed orally over a period of at least 2 weeks at a dose selected from 62.5 mg b.i.d., 125 mg.b.i.d., 250 mg b.i.d., and 500 mg b.i.d.,

10. The compound or a pharmaceutically acceptable salt thereof, or a solvate or the salt of a solvate thereof, or an active metabolite thereof for use according to any one of claims 1-5, wherein the compound is dosed orally over a period of at least 4 weeks at a dose selected from 62.5 mg b.i.d., 125 mg.b.i.d., 250 mg b.i.d., and 500 mg b.i.d..

11. The compound or a pharmaceutically acceptable salt thereof, or a solvate or the salt of a solvate thereof, or an active metabolite thereof for use according to any one of claims 1-5, wherein the compound is dosed orally over a period of at least 4 weeks at a dose selected from 62.5 mg b.i.d., 125 mg.b.i.d., 250 mg b.i.d., and 500 mg b.i.d, wherein a ppFEVl decrease of no more than 1%, no more than 2%, or no more than 3% compared to pre-dosing levels is seen in a non-naive subject.

12. The compound or a pharmaceutically acceptable salt thereof, or a solvate or the salt of a solvate thereof, or an active metabolite thereof for use according to any one of claims 1-5, wherein the compound is dosed orally over a period of at least 2 weeks at a dose selected from 62.5 mg b.i.d., 125 mg.b.i.d., 250 mg b.i.d., and 500 mg b.i.d, wherein a ppFEVl decrease of no more than 1%, no more than 2%, or no more than 3% compared to pre-dosing levels is seen in a non-naive subject.

13. The compound or a pharmaceutically acceptable salt thereof, or a solvate or the salt of a solvate thereof, or an active metabolite thereof for use according to any one of claims 1-5, wherein the compound is dosed orally over a period of at least 4 weeks at a dose selected from 62.5 mg b.i.d., 125 mg.b.i.d., 250 mg b.i.d., and 500 mg b.i.d, wherein a ppFEVl increase of at least 1% compared to pre-dosing levels, in a naive subject.

14. The compound or a pharmaceutically acceptable salt thereof, or a solvate or the salt of a solvate thereof, or an active metabolite thereof for use according to any one of claims 1-5, wherein the compound is dosed orally over a period of at least 2 weeks at a dose selected from 62.5 mg b.i.d., 125 mg.b.i.d., 250 mg b.i.d., and 500 mg b.i.d, wherein a ppFEVl increase of at least 1% compared to pre-dosing levels, in a na^'ive subject.

15. The compound or a pharmaceutically acceptable salt thereof, or a solvate or the salt of a solvate thereof, or an active metabolite thereof for use according to any one of claims 1-5, wherein the compound is dosed orally over a period of at least 2 weeks at a dose selected from 62.5 mg b.i.d., 125 mg.b.i.d., 250 mg b.i.d., and 500 mg b.i.d, wherein a sweat chloride decrease at least 5 mmol L, at least 10 mmol/L, at least 15 mmol/L, at least 20 mmol/L, at least 25 mmol/L, at least 30 mmol/L, at least 35 mmol/L, at least 40 mmol/L, at least 45 mmol/L, or at least 50 mmol L, is seen compared to pre-dosing levels.

16. The compound or a pharmaceutically acceptable salt thereof, or a solvate or the salt of a solvate thereof, or an active metabolite thereof for use according to any one of claims 1-5, wherein the compound is dosed orally over a period of at least 2 weeks at a dose selected from 62.5 mg b.i.d., 125 mg.b.i.d., 250 mg b.i.d., and 500 mg b.i.d, wherein a sweat chloride decrease at least 5 mmol L, at least 10 mmol/L, at least 15 mmol/L, at least 20 mmol/L, at least 25 mmol/L, at least 30 mmol/L, at least 35 mmol/L, at least 40 mmol/L, at least 45 mmol/L, or at least 50 mmol/L, is seen compared to pre-dosing levels.

17. The compound or a pharmaceutically acceptable salt thereof, or a solvate or the salt of a solvate thereof, or an active metabolite thereof for use according to any one of claims 1-5, wherein the compound is dosed orally at a dose sufficient to reach in vivo exposures of at least 80 ng/mL, at least 100 ng/mL, at least 120 ng/mL, at least 140 ng/mL, at least 160 ng/mL, at least 180 ng/mL, or least 200 ng/mL.

18. The compound or a pharmaceutically acceptable salt thereof, or a solvate or the salt of a solvate thereof, or an active metabolite thereof for use according to claim 17, wherein the compound is dosed at 500 mg b.i.d.