Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K31/00—Medicinal preparations containing organic active ingredients
  • A61K31/33—Heterocyclic compounds
  • A61K31/395—Heterocyclic compounds having nitrogen as a ring hetero atom, e.g. guanethidine or rifamycins
  • A61K31/495—Heterocyclic compounds having nitrogen as a ring hetero atom, e.g. guanethidine or rifamycins having six-membered rings with two or more nitrogen atoms as the only ring heteroatoms, e.g. piperazine or tetrazines
  • A61K31/505—Pyrimidines; Hydrogenated pyrimidines, e.g. trimethoprim
  • A61K31/506—Pyrimidines; Hydrogenated pyrimidines, e.g. trimethoprim not condensed and containing further heterocyclic rings
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K31/00—Medicinal preparations containing organic active ingredients
  • A61K31/33—Heterocyclic compounds
  • A61K31/395—Heterocyclic compounds having nitrogen as a ring hetero atom, e.g. guanethidine or rifamycins
  • A61K31/495—Heterocyclic compounds having nitrogen as a ring hetero atom, e.g. guanethidine or rifamycins having six-membered rings with two or more nitrogen atoms as the only ring heteroatoms, e.g. piperazine or tetrazines
  • A61K31/4965—Non-condensed pyrazines
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K31/00—Medicinal preparations containing organic active ingredients
  • A61K31/33—Heterocyclic compounds
  • A61K31/395—Heterocyclic compounds having nitrogen as a ring hetero atom, e.g. guanethidine or rifamycins
  • A61K31/495—Heterocyclic compounds having nitrogen as a ring hetero atom, e.g. guanethidine or rifamycins having six-membered rings with two or more nitrogen atoms as the only ring heteroatoms, e.g. piperazine or tetrazines
  • A61K31/4985—Pyrazines or piperazines ortho- or peri-condensed with heterocyclic ring systems
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K31/00—Medicinal preparations containing organic active ingredients
  • A61K31/33—Heterocyclic compounds
  • A61K31/395—Heterocyclic compounds having nitrogen as a ring hetero atom, e.g. guanethidine or rifamycins
  • A61K31/495—Heterocyclic compounds having nitrogen as a ring hetero atom, e.g. guanethidine or rifamycins having six-membered rings with two or more nitrogen atoms as the only ring heteroatoms, e.g. piperazine or tetrazines
  • A61K31/505—Pyrimidines; Hydrogenated pyrimidines, e.g. trimethoprim
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K31/00—Medicinal preparations containing organic active ingredients
  • A61K31/33—Heterocyclic compounds
  • A61K31/395—Heterocyclic compounds having nitrogen as a ring hetero atom, e.g. guanethidine or rifamycins
  • A61K31/495—Heterocyclic compounds having nitrogen as a ring hetero atom, e.g. guanethidine or rifamycins having six-membered rings with two or more nitrogen atoms as the only ring heteroatoms, e.g. piperazine or tetrazines
  • A61K31/505—Pyrimidines; Hydrogenated pyrimidines, e.g. trimethoprim
  • A61K31/513—Pyrimidines; Hydrogenated pyrimidines, e.g. trimethoprim having oxo groups directly attached to the heterocyclic ring, e.g. cytosine
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K31/00—Medicinal preparations containing organic active ingredients
  • A61K31/33—Heterocyclic compounds
  • A61K31/395—Heterocyclic compounds having nitrogen as a ring hetero atom, e.g. guanethidine or rifamycins
  • A61K31/495—Heterocyclic compounds having nitrogen as a ring hetero atom, e.g. guanethidine or rifamycins having six-membered rings with two or more nitrogen atoms as the only ring heteroatoms, e.g. piperazine or tetrazines
  • A61K31/505—Pyrimidines; Hydrogenated pyrimidines, e.g. trimethoprim
  • A61K31/519—Pyrimidines; Hydrogenated pyrimidines, e.g. trimethoprim ortho- or peri-condensed with heterocyclic rings
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K31/00—Medicinal preparations containing organic active ingredients
  • A61K31/557—Eicosanoids, e.g. leukotrienes or prostaglandins
  • A61K31/5575—Eicosanoids, e.g. leukotrienes or prostaglandins having a cyclopentane, e.g. prostaglandin E2, prostaglandin F2-alpha
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K31/00—Medicinal preparations containing organic active ingredients
  • A61K31/557—Eicosanoids, e.g. leukotrienes or prostaglandins
  • A61K31/5578—Eicosanoids, e.g. leukotrienes or prostaglandins having a pentalene ring system, e.g. carbacyclin, iloprost
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K45/00—Medicinal preparations containing active ingredients not provided for in groups A61K31/00 - A61K41/00
  • A61K45/06—Mixtures of active ingredients without chemical characterisation, e.g. antiphlogistics and cardiaca
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P9/00—Drugs for disorders of the cardiovascular system
  • A61P9/12—Antihypertensives
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K2300/00—Mixtures or combinations of active ingredients, wherein at least one active ingredient is fully defined in groups A61K31/00 - A61K41/00

Definitions

• the present disclosure relates to daily dosages for treating pulmonary arterial hypertension with medicinal actives.
• the present disclosure further relates to methods for treating pulmonary arterial hypertension with medicinal actives.
• Pulmonary arterial hypertension is a severe, incurable disease characterized by remodeling of the pulmonary arterial bed, leading to elevations in resting mean pulmonary artery pressures, subsequent right ventricular hypertrophy, and eventually, right heart failure and death.
• Current standard-of care therapies for PAH target three different pathways - namely, the endothelin-1 pathway, the nitric oxide pathway, and the prostacyclin pathway. Humbert M. Ghofrani H-A. Thorax 2016: 71;73-83. doi: 10.1136/thoraxjnl-2015-207170.
• a drug-drug interaction study conducted with gemfibrozil (a strong irreversible inhibitor of CYP2C8) and selexipag determined that concomitant administration with selexipag and strong inhibitors of CYP2C8 must be avoided based on an 11-fold increase in ACT-333679 AUCo- ⁇ .
• the incidence and/or intensity of AEs reported after concomitant administration of selexipag and gemfibrozil were significantly higher than those following the administration of selexipag alone, which is in line with the observed increase in exposure to the active metabolite ACT-333679, the major contributor to the effect of selexipag in humans. [Bruderer et al., 2017].
• Rodatristat ethyl (RVT-1201) is a pro-drug for the active tryptophan hydroxylase (TPH1) inhibitor rodatristat (KAR5417) and is in development for PAH. Following oral administration, rodatristat ethyl is rapidly absorbed and hydrolyzed to KAR5417. It would be desirable to have a dosage system and method of combining rodatristat ethyl or KAR5417 with an FDA-approved PAH pharmaceutical active to provide enhanced efficacy in treating the symptoms or side effects of PAH compared to either the rodatristat ethyl/KAR5417 or the FDA-approved active alone. It would further be desirable to have a dosage system and method that provides a high, steady state exposure by Day 7 in a human patient receiving doses of up to 600 mg BID rodatristat ethyl.
• a daily dosage for treating pulmonary arterial hypertension has two discrete dosage forms, wherein each of the dosage forms includes an amount of up to 600 mg of rodatristat ethyl.
• a method for treating pulmonary arterial hypertension has the step of administering to a human patient in need thereof an individual dosage amount of up to 600 mg of rodatristat ethyl twice per day.
• Another method for treating pulmonary arterial hypertension includes the step of administering to a human patient in need thereof an amount of up to 1200 mg of rodatristat ethyl once per day.
• the method has the step of administering daily to a human patient in need thereof (A) an amount of up to 1200 mg of a first compound of rodatristat ethyl and (B) an amount of a second compound selected from the group consisting of ambrisentan, sildenafil, tadalafil, bosentan, treprostinil, selexipag, and two or more of the foregoing.
• the first compound and the second compound are in a combination that results in an additive or synergistic reduction in symptoms of pulmonary arterial hypertension compared to the first compound and the second compound alone with a low risk for drug-drug interactions.
• another method for treating pulmonary arterial hypertension includes a step of administering to a human patient in need thereof (A) an amount of a first compound of rodatristat ethyl and (B) an amount of a second compound selected from the group consisting of ambrisentan, sildenafil, tadalafil, bosentan, treprostinil, selexipag, and two or more of the foregoing.
• the first compound and the second compound are in a combination that results in a synergistic or additive reduction in symptoms of pulmonary arterial hypertension compared to the first compound and the second compound alone, and wherein the amount of rodatristat ethyl results in a C max, unbound in the bloodstream of less than 0.028 ⁇ M.
• another method for treating pulmonary arterial hypertension includes a step of administering to a human patient in need thereof (A) an amount of a first compound of rodatristat ethyl and (B) an amount of a second compound selected from the group consisting of ambrisentan, sildenafil, tadalafil, bosentan, treprostinil, selexipag, macitenta ⁇ and two or more of the foregoing, wherein the first compound and the second compound are in a combination that results in a synergistic reduction in side effects of pulmonary arterial hypertension compared to the first compound and the second compound alone or additively, and wherein the amount of KAR5417 results in a C max, unbound in the bloodstream of less than 0.028 ⁇ M.
• another method for treating pulmonary arterial hypertension includes a step of administering to a human patient in need thereof (A) an amount of a first compound of rodatristat ethyl and (B) an amount of a second compound selected from the group consisting of ambrisentan, sildenafil, tadalafil, bosentan, treprostinil, selexipag, macitentan ⁇ and two or more of the foregoing, wherein the first compound and the second compound are in a combination that results in a synergistic reduction in side effects of pulmonary arterial hypertension compared to the first compound and the second compound alone or additively, and wherein the sum amount of rodatristat ethyl and KAR5417 results in a combined C max, unbound in the bloodstream of less than 0.028 ⁇ M.
• yet another method for treating pulmonary arterial hypertension includes a step of administering daily to a human patient in need thereof (A) an amount of a first compound of rodatristat ethyl and (B) an amount of a second compound selected from the group consisting of ambrisentan, sildenafil, tadalafil, bosentan, treprostinil, selexipag, macitentan and two or more of the foregoing.
• the first compound and the second compound are in a combination that results in a synergistic reduction in side effects of pulmonary arterial hypertension compared to the first compound and the second compound alone or additively, and wherein neither the first compound nor its active metabolite rodatristat substantially impact metabolism of the second compound in the bloodstream.
• yet another method for treating pulmonary arterial hypertension includes a step of administering daily to a human patient in need thereof (A) an amount of a first compound of rodatristat ethyl and (B) an amount of a second compound selected from the group consisting of ambrisentan, sildenafil, tadalafil, bosentan, treprostinil, selexipag, macitentan and two or more of the foregoing.
• the rodatristat ethyl and its active metabolite rodatristat exhibit an IC50 of ⁇ 30 ⁇ M for one or more of the enzyme group consisting of the enzyme group consisting of CYP1A2, CYP2C9, CYP2C19, and CYP2D6 in the bloodstream.
• yet another method for treating pulmonary arterial hypertension includes a step of administering daily to a human patient in need thereof (A) an amount of a first compound of rodatristat ethyl and (B) an amount of a second compound selected from the group consisting of ambrisentan, sildenafil, tadalafil, bosentan, treprostinil, selexipag, macitentan and two or more of the foregoing.
• the rodatristat ethyl and its active metabolite rodatristat exhibit an IC50 of ⁇ 30 ⁇ M for one or more of the enzyme group consisting of the enzyme group consisting of CYP1A2, CYP2B6, CYP2C9, CYP2C19, CYP2D6, and CYP3A4.
• a method for treating pulmonary arterial hypertension that includes the step of administering to a human patient in need thereof a therapeutically effect amount of rodatristat ethyl, Form 3.
• Fig. 1 is a plot of an XRPD of a crystalline compound of (S)-ethyl 8-(2-amino-6-((R)-1-(5- chloro-[1,1'-biphenyl]-2-yl)-2,2,2-trifluoroethoxy)pyrimidin-4-yl)-2,8-diazaspiro[4.5]decane-3- carboxylate according to the present disclosure (crystalline Form 3).
• Fig. 2 is a plot of an XRPD of a crystalline compound of (S)-ethyl 8-(2-amino-6-((R)-1-(5- chloro-[1,1'-biphenyl]-2-yl)-2,2,2-trifluoroethoxy)pyrimidin-4-yl)-2,8-diazaspiro[4.5]decane-3- carboxylate of a different polymorphic form than that of Fig. 1 (crystalline Form 1).
• Fig. 3 shows the predicted C max for the 600 mg BID dose for RE with a low risk for CYP inhibition.
• Fig. 4 shows the predicted C max for the 600 mg BID dose for R predicts with a low risk for
• Fig. 5 shows a indexing solution for RVT-1201-KAR5585, Lot CS14-075Aa-1704, Form 3, LIMS No. 470337.
• Rodatristat is metabolically stable and has low potential for drug interactions with PAH medications. There is low potential for metabolic drug-drug interactions (DDIs) between rodatristat ethyl and approved medications for pulmonary arterial hypertension (PAH).
• DCIs metabolic drug-drug interactions
• Rodatristat ethyl is in Phase 2 clinical development (ELEVATE 2 Study) for PAH.
• RE is an orally bioavailable pro-drug for the tryptophan hydroxylase (TPH) inhibitor, rodatristat (R).
• TPH1 is the rate-limiting enzyme for peripheral biosynthesis of serotonin (5-HT) and is up- regulated in PAH. Excess 5-HT has been implicated in the pathology of PAH. See MacLean, M.R. 2018. The serotonin hypothesis in pulmonary hypertension revisited: targets for novel therapies. Pulm Circ. 8 (2). 1-9.
• Rodatristat ethyl is a pro-drug for the active tryptophan hydroxylase (TPH1) inhibitor KAR5417 and is in development for PAH. Following oral administration, rodatristat ethyl is rapidly absorbed and hydrolyzed to KAR5417. The highest exposures achieved in healthy subjects to date were reached on Day 7 following 800 mg twice per day (BID) doses of rodatristat ethyl. Rodatristat ethyl and KAR5417 inhibit CYP2C8 in vitro, but have been determined to have a weak potential to cause a clinically relevant inhibitory interaction with this enzyme in humans receiving doses of up to 600 mg BID rodatristat ethyl.
• TPH1 active tryptophan hydroxylase
• PAH treatment sometimes employs combination therapy regimens and understanding drug-drug interactions (DDI) potential is an important feature in managing patient care.
• DAI drug-drug interactions
• a drug- drug interaction study has been conducted to determine the effect, if any, of rodatristat ethyl steady-state dosing has on the pharmacokinetics (PK) of selexipag and its metabolite ACT- 333679.
• PK pharmacokinetics
• (S)-ethyl 8-(2-amino-6-((R)-1-(5-chloro-[1,1'-biphenyl]-2-yl)-2,2,2- trifluoroethoxy)pyrimidin-4-yl)-2,8-diazaspiro[4.5]decane-3-carboxylate is referred to herein rodatristat ethyl (RE) and in the literature also as KAR5585 and RVT-1201.
• Rodatristat ethyl has the following structure:
• the amorphous form of (S)-ethyl 8-(2-amino-6-((R)-1-(5-chloro-[1,1'-biphenyl]-2-yl)- 2,2,2-trifluoroethoxy)pyrimidin-4-yl)-2,8-diazaspiro[4.5]decane-3-carboxylate can be prepared by the method set forth in Example 63i of U.S. Patent No. 9,199,994, which is incorporated herein by reference in its entirety.
• the amorphous form can then be converted to crystalline form by methods described in U.S. Patent Publication 2020/0148681 A1, published May 14, 2020, which is incorporated herein by reference in its entirety.
• Forms 1 and 3 can be prepared by the methods set forth in U.S. Patent Publication 2020/0148681 Al.
• Form 3 exhibits the following x-ray powder diffraction pattern (XRPD):
• the x-ray powder diffraction pattern is carried out with a Cu Ka radiation source according to the following method:
• Selected XRPD patterns were collected with a PANalytical X'Pert PRO MPD diffractometer using an incident beam of Cu K ⁇ radiation produced using a long, fine-focus source and a nickel filter.
• the diffractometer was configured using the symmetric Bragg- Brentano geometry.
• a silicon specimen NIST SRM 640e was analyzed to verify the observed position of the Si 111 peak is consistent with the NIST-certified position.
• a specimen of the sample was prepared as a thin, circular layer centered on a silicon zero- background substrate.
• Antiscatter slits (SS) were used to minimize the background generated by air.
• Soller slits for the incident and diffracted beams were used to minimize broadening from axial divergence.
• Diffraction patterns were collected using a scanning position-sensitive detector (X'Celerator) located 240 mm from the sample and Data Collector software v. 2.2b.
• the data acquisition parameters for each pattern are displayed above the image in the Data section of this report including the divergence slit (DS) and the incident-beam SS.
• FIG. 5 An indexing solution for rodatristat ethyl is shown in Fig. 5.
• rodatristat ethyl is (S)-8-(2-amino-6-((R)-1-(5-chloro-[1,1'-biphenyl]-2- yl)-2,2,2-trifluoroeth-oxy)pyrimidin-4-yl)-2,8-diazaspiro[4.5]decane-3-carboxylic acid, which is of the formula
• rodatristat (S)-8-(2-amino-6-((R)-1-(5-chloro-[1,1'-biphenyl]-2-yl)-2,2,2-trifluoroeth-oxy)pyrimidin-4- yl)-2,8-diazaspiro[4.5]decane-3-carboxylic acid is referred to herein as rodatristat.
• Rodatristat is also referred to in the literature as KAR5417. When rodatristat ethyl enters the bloodstream, it substantially converts to rodatristat.
• the amorphous form of KAR5417 can be prepared by the method set forth in Example 34c of U.S. Patent No. 9,199,994, which again is incorporated herein in its entirety.
• Sildenafil citrate is the citrate salt of sildenafil, a selective inhibitor of cyclic guanosine monophosphate (cGMP)-specific phosphodiesterase type 5 (PDE5).
• Sildenafil citrate is designated chemically as 1-[[3-(6,7-dihydro-1-methyl-7-oxo-3-propyl-1H-pyrazolo[4,3- d]pyrimidin-5-yl)-4-ethoxyphenyl]sulfonyl]-4-methylpiperazine citrate and has the following structural formula:
• Tadalafil a PDE-5 inhibitor
• Bosentan is an endothelin receptor antagonist belonging to a class of highly substituted pyrimidine derivatives, with no chiral centers. It is designated chemically as 4-tert-butyl-N-[6- (2-hydroxy-ethoxy)-5-(2-methoxy-phenoxy)-[2,2']-bipyrimidin4-yl]- benzenesulfonamide monohydrate and has the following structural formula: Ambrisentan is an endothelin receptor antagonist selective for the endothelin type-A (ETA) receptor.
• ETA endothelin type-A
• ambrisentan is (+)-(2S)-2-[(4,6-dimethylpyrimidin-2- yl)oxy]-3-methoxy-3,3-diphenylpropanoic acid. It contains a single chiral center determined to be the (S) configuration and has the following structural formula:
• Selexipag is prostacyclin receptor agonist that causes vasodilation in pulmonary vasculature.
• Selexipag is class of pyrazines that is N-(methanesulfonyl)-2- ⁇ 4-[(propan-2- yl)(pyrazin-2-yl)amino]butoxy ⁇ acetamide carrying two additional phenyl substituents at positions 5 and 6 on the pyrazine ring. It has the following structural formula:
• Treprostinil is a prostacycline vasodilator.
• Treprostinil (sodium) is (1R,2R,3aS,9aS)- [[2,3,3a,4,9,9a-Hexahydro-2-hydroxy-1-[(3S)-3-hydroxyoctyl]-1Hbenz[f]inden-5-yl]oxy]acetic acid monosodium salt. It has the following structural formula:
• Macitentan is an endothelin receptor antagonist (ERA). Macitentan blocks the ET1- dependent rise in intracellular calcium by inhibiting the binding of ET-1 to ET receptors. Blocking of the ETA receptor subtype seems to be of more importance in the treatment of PAH than blocking of ETB, likely because there are higher numbers of ETA receptors than ETB receptors in pulmonary arterial smooth muscle cells.
• the chemical formula is N-[5-(4- Bromophenyl)-6-[2-[(5-bromo-2-pyrimidinyl)oxy]etboxy]-4-pyrimidinyl]-N'-propyl-suifamide. The CAS number is 441798-33-0.
• the structural formula is the following:
• the phrase "therapeutically effective amount” refers to the amount of active compound or pharmaceutical agent that elicits the biological or medicinal response in a tissue, system, individual or human that is being sought by a researcher, medical doctor or other clinician.
• treating refers to 1) inhibiting the disease; for example, inhibiting a disease, condition or disorder in an individual who is experiencing or displaying the pathology or symptomatology of the disease, condition or disorder (i.e., arresting further development of the pathology and/or symptomatology), or 2) ameliorating the disease; for example, ameliorating a disease, condition or disorder in an individual who is experiencing or displaying the pathology or symptomatology of the disease, condition or disorder (i.e., reversing the pathology and/or symptomatology).
• a compound of this disclosure can be administered orally, subcutaneously, topically, parenterally, by inhalation spray or recta lly in dosage unit formulations containing conventional non-toxic pharmaceutically acceptable carriers, adjuvants and vehicles.
• Parenteral administration can involve subcutaneous injections, intravenous or intramuscular injections or infusion techniques.
• compositions can be prepared as solid dosage forms for oral administration (e.g., capsules, tablets, pills, dragees, powders, granules and the like).
• a tablet can be prepared by compression or molding.
• Compressed tablets can include one or more binders, lubricants, glidants, inert diluents, preservatives, disintegrants, or dispersing agents.
• Tablets and other solid dosage forms, such as capsules, pills and granules can include coatings, such as enteric coatings.
• rodatristat ethyl and rodatristat to be administered will vary depending on factors such as the following: the compound selected, method of administration, release profile, and composition formulation.
• a typical dosage will be a therapeutic amount of about 1 mg/kg/day to about 50 mg/kg/day and more typically from about 5 mg/kg/day to about 30 mg/kg/day, based on the weight of the patient.
• a most preferred compound is rodatristat ethyl in crystalline Form 3.
• Individual oral dosage forms typically have therapeutic amounts from about 50 mg to about 3000 mg of rodatristat ethyl and additional amounts of one or more pharmaceutically acceptable excipients.
• Other useful individual oral dosage forms can, by way of example, have rodatristat ethyl or rodatristat in amounts of 100 mg, 150 mg, 200 mg, 250 mg, 300 mg, 350 mg, or 400 mg, 450 mg, 500 mg, 550 mg, 575 mg, 600 mg, 625 mg, 650 mg, 675 mg, 700 mg, 725 mg, 750 mg, 775 mg, 800 mg, 900 mg, 950 mg, 1000 mg, 1050 mg, 1100 mg, 1150 mg, and about 1200 mg, particularly 600 mg and 1200 mg.
• a preferred dosage is 1200 mg.
• Other amounts between 50 mg to 3000 mg are possible, for example, from about 325 mg to about 475 mg, from about 350 mg to about 500 mg, from about 375 to about 525mg, from about 400 mg to about 550 mg, from about 425 mg to about 575 mg, from about 450 mg to about 600 mg, from about 475 mg to about 625 mg, from about 500 mg to about 650 mg, from about 525 mg to about 675 mg, from about 550 mg to about 700 mg, from about 575 mg to about 725 mg, from about 600 mg to about 750 mg, from about 625 mg to about 775mg, from about 650 mg to about 800 mg, from about 675 mg to about 825 mg, from about 700 mg to about 850 mg, from about 725 mg to about 875 mg, from about 750 mg to about 900 mg, from about 775 mg to about 925 mg, from about 800 mg to about 950 mg, from about 825 to about 975, from about 850 mg to about 1000 mg, from about 900 mg to about 1150
• a preferred oral dosage form has up to 600 mg of rodatristat ethyl, most preferably Form 3, taken twice per day (BID), for a total of up to 1200 mg per day.
• Another preferred oral dosage form has up to 300 mg of rodatristat ethyl, most preferably Form 3, taken twice per day, for a total of up to 600 mg per day. It is also possible to take these preferred dosage forms on a once-per-day (SID) basis.
• PAH treatable according to the methods disclosed herein include (1) idiopathic (IPAH), (2) familial (FPAH), and (3) associated (APAH) which is the most common type of PAH.
• PAH associated with other medical conditions including, for example, (1) collagen vascular disease (or connective tissue disease) which include autoimmune diseases such as scleroderma or lupus; (2) congenital heart and lung disease; (3) portal hypertension (e.g., resulting from liver disease); (4) HIV infection; and (5) drugs (e.g., appetite suppressants, cocaine, and amphetamines).
• collagen vascular disease or connective tissue disease
• portal hypertension e.g., resulting from liver disease
• drugs e.g., appetite suppressants, cocaine, and amphetamines.
• APAH can also be PAH associated with abnormal narrowing in the pulmonary veins and/or capillaries such as in pulmonary veno-occlusive disease (PVOD) and pulmonary capillary hemangiomatosis.
• PVOD pulmonary veno-occlusive disease
• PPHN pulmonary capillary hemangiomatosis
• Another type of PAH is associated with persistent pulmonary hypertension of the newborn (PPHN).
• Dosages/compositions according to the present disclosure include combinations of rodatristat ethyl and/or rodatristat with one or more of the other FDA-approved PAH pharmaceutical actives disclosed above.
• Preferred dosages/compositions are combinations of rodatristat ethyl and the other PAH pharmaceutical actives.
• a most preferred combination is rodatristat ethyl and selexipag.
• Oral dosage forms are preferred, although other forms of administration, e.g., parenteral, are possible.
• a preferred dosage regimen of rodatristat ethyl and selexipag takes the form of up to 1200 mg of rodatristat ethyl and up to 2400 meg of selexipag per day.
• a more preferred dosage regimen is up to 600 mg of rodatristat ethyl and up to 1200 meg of selexipag twice per day.
• a still more preferred embodiment is about 200 mg to 600 mg of rodatristat ethyl and about 200 meg to about 1200 meg of selexipag twice per day.
• a most preferred embodiment is about 400 mg to 600 mg of rodatristat ethyl and about 200 meg to about 1200 meg of selexipag twice per day.
• An oral dosage regimen is preferred.
• the rodatristat ethyl and selexipag can be administered in the same dosage form or in separate dosage forms.
• a preferred dosage regimen of rodatristat ethyl and sildenafil citrate takes the form of up to 1200 mg of rodatristat ethyl and up to 60 mg of sildenafil citrate per day.
• a more preferred dosage regimen is up to 600 mg of rodatristat ethyl and up to 30 mg of sildenafil citrate twice per day.
• a still more preferred embodiment is about 200 mg to 600 mg of rodatristat ethyl and about 10 mg to about 30 mg of sildenafil citrate twice per day.
• a most preferred embodiment is about 400 mg to 600 mg of rodatristat ethyl and about 20 mg to about 30 mg of sildenafil citrate twice per day.
• An oral dosage regimen is preferred.
• the rodatristat ethyl and sildenafil citrate can be administered in the same dosage form or in separate dosage forms.
• a preferred dosage regimen of rodatristat ethyl and tadalafil takes the form of up to 1200 mg of rodatristat ethyl and up to 40 mg of tadalafil per day.
• a more preferred dosage regimen is up to 600 mg of rodatristat ethyl and up to 20 mg of tadalafil twice per day.
• a still more preferred embodiment is about 200 mg to 600 mg of tadalafil and about 6.67 mg to about 20 mg of tadalafil twice per day.
• a most preferred embodiment is about 400 mg to 600 mg of rodatristat ethyl and about 13.33 mg to about 20 mg of tadalafil twice per day.
• An oral dosage regimen is preferred.
• the rodatristat ethyl and tadalafil can be administered in the same dosage form or in separate dosage forms.
• a preferred dosage regimen of rodatristat ethyl and bosentan takes the form of up to 1200 mg of rodatristat ethyl and up to 250 mg of bosentan per day.
• a more preferred dosage regimen is up to 600 mg of rodatristat ethyl and up to 125 mg of bosentan twice per day.
• a still more preferred embodiment is about 200 mg to 600 mg of rodatristat ethyl and about 62.5 mg to about 125 mg of bosentan twice per day.
• a most preferred embodiment is about 400 mg to 600 mg of rodatristat ethyl and about 62.5 mg to about 125 mg of bosentan twice per day.
• An oral dosage regimen is preferred.
• the rodatristat ethyl and bosentan can be administered in the same dosage form or in separate dosage forms.
• a preferred dosage regimen of rodatristat ethyl and ambrisentan takes the form of up to 1200 mg of rodatristat ethyl and up to 10 mg of ambrisentan per day.
• a more preferred dosage regimen is up to 600 mg of rodatristat ethyl and up to 5 mg of ambrisentan twice per day.
• a still more preferred embodiment is about 200 mg to 600 mg of rodatristat ethyl and about 2.5 mg to about 5 mg of ambrisentan twice per day.
• a most preferred embodiment is about 400 mg to 600 mg of rodatristat ethyl and about 2.5 mg to about 5 mg of ambrisentan twice per day.
• An oral dosage regimen is preferred.
• the rodatristat ethyl and ambrisentan can be administered in the same dosage form or in separate dosage forms.
• a preferred dosage regimen of rodatristat ethyl and treprostinil takes the form of up to 1200 mg of rodatristat ethyl and up to 24 mg of treprostinil per day.
• a more preferred dosage regimen is up to 600 mg of rodatristat ethyl and up to 12 mg of treprostinil twice per day.
• a still more preferred embodiment is about 200 mg to 600 mg of treprostinil and about 4 mg to about 12 mg of treprostinil twice per day.
• a most preferred embodiment is about 400 mg to 600 mg of rodatristat ethyl and about 8 mg to about 12 mg of treprostinil twice per day.
• An oral dosage regimen is preferred.
• the rodatristat ethyl and treprostinil can be administered in the same dosage form or in separate dosage forms.
• a preferred dosage regimen of rodatristat ethyl and macitentan takes the form of up to 1200 mg of rodatristat ethyl and up to 10 mg of macitentan per day.
• a more preferred dosage regimen is up to 600 mg of rodatristat ethyl and up to 5 mg of macitentan twice per day.
• a still more preferred embodiment is about 200 mg to 600 mg of macitentan and about 2.5 mg to about 5 mg of macitentan twice per day.
• a most preferred embodiment is about 400 mg to 600 mg of rodatristat ethyl and about 2.5 mg to about 5 mg of macitentan twice per day.
• An oral dosage regimen is preferred.
• the rodatristat ethyl and macitentan can be administered in the same dosage form or in separate dosage forms.
• rodatristat ethyl or rodatristat with two or more of the other PAH actives.
• a useful combination is a three-drug combination of rodatristat ethyl/tadalafil/ambrisentan.
• Combinations of rodatristat and/or rodatristat ethyl with one or more of the other FDA- approved PAH pharmaceutical actives are formulated such that one or more of the following are accomplished: (A) the risk of DDI interactions is low, (B) synergistic or additive reduction in symptoms of PAH compared to the rodatristat/rodatristat ethyl and the FDA-approved PAH pharmaceutical active(s) alone, and (C) synergistic or additive reduction in side effects of PAH compared to the rodatristat/rodatristat ethyl and the FDA-approved PAH pharmaceutical active(s) alone.
• Symptoms of PAH include the following: fatigue, lethargy, exertional dyspnea, presyncope/syncope, cough, hoarseness, hypotension, fluid retention, lower extremity edema, chest pain, and cyanosis.
• Side effects of PAH include the following: the aforementioned symptoms, side effects of multi-drug treatment regimens and diminished quality of life for the patient and family caregivers.
• a method for treating pulmonary arterial hypertension comprising administering daily to a human patient in need thereof a therapeutic dose of (A) an amount of a first compound of rodatristat ethyl and (B) an amount of a second compound selected from the group consisting of ambrisentan, sildenafil, tadalafil, bosentan, treprostinil, selexipag, macitentan, and two or more of the foregoing, wherein the rodatristat ethyl and its active metabolite rodatristat exhibit an IC 50 of ⁇ 30 ⁇ M for one or more of the enzyme group consisting of CYP1A2, CYP2C9, CYP2C19, and CYP2D6 in the bloodstream.
• IC 50 is measured according to the in vitro CYP inhibition method/technique using pooled human microsomes.
• a method for treating pulmonary arterial hypertension comprising administering daily to a human patient in need thereof a therapeutic dose of (A) an amount of a first compound of rodatristat ethyl and (B) an amount of a second compound selected from the group consisting of ambrisentan, sildenafil, tadalafil, bosentan, treprostinil, selexipag, macitentan, and two or more of the foregoing, wherein the rodatristat ethyl and its active metabolite rodatristat exhibit an IC 50 of ⁇ 30 ⁇ M for one or more of the enzyme group consisting of CYP1A2, CYP2B6, CYP2C9, CYP2C19, CYP2D6, and CYP3A4.
• IC 50 is measured according to the in vitro CYP inhibition method/technique using pooled human microsomes.
• Rodatristat Ethyl Assessment of Potential for Metabolism or Transporter-based Drug-Drug
• rodatristat ethyl or rodatristat were perpetrators of drug-drug interactions across in vitro CYP and transporter studies (Tables 1-4). Where appropriate, IC 50 values were compared to the predicted mean maximum plasma concentrations (C max ) of rodatristat ethyl (149 ng/mL, 0.252 ⁇ M) and rodatristat (1130 ng/mL, 2.01 ⁇ M) in plasma ELEVATE1 and highest dose level in ELEVATE2 (600mg rodatristat ethyl dosed bid). This analysis was performed to assess the potential for clinically meaningful DDIs as recommended in FDA Draft Guidance: "In Vitro Metabolism- and Transporter-Mediated Drug- Drug Interaction Studies Guidance for Industry"; Oct 2017 (FDA, 2017).
• Rodatristat ethyl and rodatristat are not major substrates for key CYP enzymes and are not time-dependent inhibitors of CYP isoforms evaluated.
• rodatristat ethyl The metabolism of rodatristat ethyl is predominantly by esterase mediated hydrolysis of the ester pro-drug moiety to rodatristat in liver tissue preparations from human, rat, dog, and cynomolgus monkey, and intestinal and lung tissues from rat and human. Hydrolysis of rodatristat ethyl was also observed in rat blood, and to a much lesser extent in dog and human blood. Rodatristat is metabolically stable in liver preparations across species and is largely eliminated unchanged in bile (rat).
• Rodatristat ethyl directly inhibited CYP2B6, CYP2C8, and CYP3A4/5 (for both midazolam 1' hydroxylation and testosterone 6b hydroxylation) with IC50 values of 13 ⁇ M, 2.8 ⁇ M, 13 ⁇ M, and 23 ⁇ M, respectively. There was no evidence of clinically meaningful direct inhibition of CYP1A2, CYP2C9, CYP2C19, or CYP2D6 by rodatristat ethyl as the IC50 values were greater than 30 ⁇ M.
• the predicted clinical C max for rodatristat ethyl for the proposed 600 mg BID regimen is 0.252 ⁇ M, which is ⁇ 10 fold lower than the IC 50 for the most sensitive CYP isoform 2C8 (IC50 2.8 ⁇ M), indicating rodatristat ethyl has low potential to cause a CYP2C8 based interaction.
• Inhibition of CYP3A while low risk systemically, does meet threshold for potential intestinal interaction. This is determined from the dose and estimated exposure in the gut lumen versus Ki ( R1,gut). The R1 value calculated for midazolam is >600 and exceeds the threshold of 11.
• Rodatristat elicited weak inhibition of CYPs 2B6, 2C9, and 3A4/5, with 27 to 45% inhibition across these isoforms at 30 ⁇ M rodatristat, indicating IC 50 values are > 30 ⁇ M and > 14x the envisaged rodatristat clinical C max (2.01 ⁇ M) at steady state. Rodatristat did not inhibit CYP1A2, CYP2C19, CYP2D6.
• Rodatristat directly inhibited CYP2C8 with an IC 50 value of 2.8 ⁇ M.
• the FDA guidance recommends contextualizing IC 50 values relative to unbound C max values in plasma.
• the R value for rodatristat is 1.014 supportive of low risk for a clinically meaningful interaction via CYP2C8.
• CYP induction was evaluated in vitro using cultured human hepatocytes from 3 donors.
• Rodatristat ethyl and rodatristat caused negligible induction of CYP1A2 ( ⁇ 2% control for the most sensitive responder), CYP2B6 (mean ⁇ SD values relative to control of 16.2 ⁇ 20.0% and 15.0 ⁇ 17.9%, respectively), and CYP3A4 (7.1 ⁇ 6.41% and 10.3 ⁇ 11.9%, respectively) mRNA at 20 ⁇ M (the highest concentration studied).
• the 20 ⁇ M concentration reflects at least ⁇ 9-fold the predicted clinical C max values predicted for the 600 mg BID dose for rodatristat ethyl (0.252 ⁇ M) and rodatristat (2.01 ⁇ M).
• Rodatristat ethyl and rodatristat inhibited OATP1B1 and OATP1B3 where IC50 values for OATP1B1 are 25.4 ⁇ M and 5.74 ⁇ M for rodatristat ethyl and rodatristat, respectively, and 12.3 ⁇ M and 1.93 ⁇ M for OATP1B3.
• the R values FDA guidance for rodatristat ethyl with OATP1B1 and OATP1B3, and rodatristat with OATP1B1 are ⁇ 1.1 indicating low potential for a clinically relevant interaction.
• the R value for rodatristat is 1.26 for OATP1B3, indicating a potential for an interaction.
• overlap of drug substrates for OATPs 1B1 and 1B3 suggests low overall risk for interactions with statins.
• Rodatristat ethyl and rodatristat demonstrate little potential to inhibitor OCT2 at concentrations of up to 20 ⁇ M (IC50 values >20 ⁇ M).
• Rodatristat weakly inhibited multidrug resistance-associated protein 2 (MRP2; by 25%) and multidrug and toxin extrusion (MATE) 1 (by 30%) at nominal concentrations of 30 ⁇ M.
• Rodatristat did not inhibit MATE2-K (up to 30 ⁇ M nominal concentration).
• Neither rodatristat ethyl nor rodatristat inhibited OAT1, OAT3, and breast cancer resistance protein (BCRP).
• rodatristat ethyl and rodatristat are not anticipated to alter the pharmacokinetics of therapeutic agents that are substrates for BCRP, OAT1, OAT3, and OCT2.
• Rodatristat ethyl is not a substrate for P-gp, BCRP, MRP2, OATP1B1, or OATP1B3.
• Rodatristat is not an in vitro substrate of MRP2, or MATE1.
• Rodatristat is an in vitro substrate of the OATP1B1 (2.22-fold accumulation at 3 ⁇ M) and OATP1B3 (9.28-fold accumulation at 3 ⁇ M) uptake transporters.
• Rodatristat is a potential substrate for P-gp and BCRP; however, owing to the very low passive permeability and compound recovery in Caco 2 and MDCK cell studies, it was not possible to obtain an accurate estimate of basolateral to apical (B A) versus apical to basolateral (A B) efflux ratios. Consequently, the elimination of rodatristat into bile may be impacted by co-administration with agents that are BCRP inhibitors.
• Rodatristat ethyl and rodatristat were weak in vitro inducers in CYPs 2B6 and 3A in human hepatocytes. Monographs of PAH medications indicate CYP2B6 is not a key metabolizing enzyme. In vitro induction of CYP3A is low and unlikely to warrant dose- adjustments.
• Treprostinil and Selexipag are primarily metabolized by CYP2C8. This isoform is inhibited by rodatristat and the potential for interaction warrants further consideration as both drugs are considered sensitive to being victims of interactions as their doses are typically titrated to effect or the highest tolerated. Inhibition of CYP2C8 by another medication could increase their exposure and the possibility of adverse events.
• C max, u, portal uses plasma C max , fraction of an oral dose absorbed (Fa) and measured unbound fraction in blood.
• C max fraction of an oral dose absorbed
• Fa oral dose absorbed
• RB blood:plasma distribution
• Walsky et al proposed a threshold where the ratio of C max , u, portal / Ki of ⁇ 0.1 is associated with low risk.
• the C max, u, portal / Ki for rodatristat was 0.128 reflecting low/moderate risk.
• Selexipag increased exposure (AUC) of selexipag and its active metabolite (ACT- 333679) by 2- and 11-fold, respectively'". Coadministration with clopidogrel did not impact selexipag exposure but increased it by 2.7-fold for the active metabolite. Coadministration with ritonavir increased exposure of selexipag ⁇ 2-fold and ⁇ 2-fold for the metabolite. Selexipag administration is contraindicated in patients taking gemfibrozil and a lowering of daily dose (to QD) is recommended with moderate inhibitors.
• AUC exposure
• ACT- 333679 active metabolite
• ritonavir increased exposure of selexipag ⁇ 2-fold and ⁇ 2-fold for the metabolite.
• Selexipag administration is contraindicated in patients taking gemfibrozil and a lowering of daily dose (to QD) is recommended with moderate inhibitors.
• ritonavir did not increase exposure to the active metabolite to a clinically meaningful extent supportive that treatment with rodatristat ethyl should not require a reduction in selexipag dose.
• Treprostinil is available in 3 formulations and 4 different routes of administration (PO, IV, SC and inhaled). IV and SC are considered bioequivalent at steady-state, inhaled achieves lower systemic exposure while delivering higher concentrations locally in lung and oral treprostinil achieves similar exposure to IV/SC with bioavailability of ⁇ 17% iv .
• the oral route likely presents the greater risk for potential DDI potential owing to the comparatively higher portal drug concentrations.
• Treprostinil is metabolized primarily by CYP2C8 and to a lesser extent CYP2C9. Neither rodatristat ethyl nor rodatristat inhibit CYP2C9.
• Ambrisentan Studies with human liver tissue indicate that ambrisentan is metabolized by CYP3A, CYP2C19, and uridine 5'-diphosphate glucuronosyltransferases (UGTs) 1A9S, 2B7S, and 1A3S (Letairis (ambrisentan) [package insert], 2018).
• UGTs uridine 5'-diphosphate glucuronosyltransferases
• Bosentan is metabolized by CYPs 2C9 and 3A4 and is consequently unlikely to be impacted by rodatristat ethyl or rodatristat (Tracleer (bosentan) [package insert], 2018). No dose adjustment was required when co-administered with the CYP3A inducer rifampin, nor ketoconazole indicating low risk of a CYP3A4-mediated or a P-gp mediated interaction with rodatristat ethyl.
• Sildenafil is metabolized primarily by CYP3A (major route) and 2C9 (minor route) and is consequently unlikely to be impacted by rodatristat ethyl or rodatristat (Revatio (sildenafil) [package insert], 2018). No dose adjustment was needed when sildenafil was co-administered with the CYP3A inducer bosentan, nor squinavir, suggesting a CYP3A4-mediated or P-gp- mediated interaction with rodatristat ethyl is unlikely.
• Tadalafil is metabolized primarily by CYP3A4 and is consequently unlikely to have metabolism-based interactions with rodatristat ethyl or rodatristat (Adcirca (tadalafil) [package insert], 2017). No dose adjustment is required when co-administered with weak to moderate CYP3A inducers. Tadalafil did not have a significant impact on the pharmacokinetics of digoxin.
• Rodatristat DDI Risk Assessment (predicted @ 600 mg BID): Transporters Overall, these data support coadministration of selexipag and rodatristat ethyl without dose adjustment, but with appropriate clinical monitoring with a focus on changes in tolerability to selexipag.
• Rodatristat ethyl and rodatristat are low risk for being systemic inhibitors of CYPs.
• Treprostinil and selexipag -sensitive CYP2C8 substrates; rodatristat inhibits CYP2C8 in vitro but presents a low-risk for clinically meaningful interaction.
• Treprostinil coadministration with strong inhibitor gemfibrozil increased Cmax and AUC by ⁇ 2-fold (ORENITRAM ® (treprostinil) monograph (revised 10/2019) https://www.accessdata.fda.gov/drugsatfda docs/label/2019/203496s011lbl.pdf. As a weaker inhibitor, it is unlikely that RE treatment would cause meaningful exposure changes.
• Treprostinil can be co-administered without dose adjustments but with appropriate clinical monitoring with a focus on changes in tolerability to treprostinil.
• Ambrisentan metabolized by CYPs 3A4, 2C19, UGTs 1A9S, 2B7S, 1A3S and is unlikely to require dose adjustment with RE. See LETAIRIS ® (ambrisentan) monograph (revised 08/2019) htps://www.accessdata.fda.gov/drugsatfda docs/label/2019/022081s041lbl.pdf.
• Bosentan metabolized by CYPs 2C9 and 3A4 and is unlikely to require dose adjustment with RE TRACLEER ® (bosentan) monograph (revised 05/2019) https://www.accessdata.fda.gov/drugsatfd3 docs/label/2019/021290s039, 209279s005lbl.pdf.
• Tildenafil metabolized by CYPs 3A (major route) and 2C9 (minor route) and is unlikely to require dose adjustment with RE- See REVATIO ® (sildenafil) monograph (revised 02/2018) https://www.accessdata.fda.gov/drugsatfda docs/label/2018/021845s018lbl.pdf.
• Tadalafil metabolized primarily by CYP3A4 and is unlikely to require dose adjustment with RE. See ADCIRCA ® (tadalafil) monograph (revised 05/2017) ⁇ https://www.accessdata.fda.gov/drugsatfda_docs/label/2017/022332s009lbl.pdf>
• PBPK physiologically based pharmacokinetic
• the PBPK model was developed based on physicochemical data, in vitro data, and refined using clinical data collected in Clinical Study RVT-1201-1001 (Regimen C; single 400 mg dose in fed subjects).
• the PBPK model was then verified by simulating the multiple-dose plasma concentration-time profile of rodatristat ethyl and rodatristat after twice daily (BID) administration of 400 mg (fed) or 800 mg (fed) rodatristat ethyl in Clinical Study RVT-1201- 1001.
• BID twice daily
• the PBPK model was further verified by simulating of the multiple-dose BID administration of 400 mg (fed) rodatristat ethyl in Clinical Study KAR5585-101.
• the simulated data were compared to observed data.
• PK pharmacokinetic
• PBPK model was then applied to simulate drug-drug interactions (DDIs) with rodatristat ethyl and rodatristat acting as perpetrators of CYP- or transporter-mediated DDIs.
• PBPK simulations of each interaction scenario included 100 virtual subjects. Population estimates of geometric mean AUC 0-inf and C max ratios were generated to predict the relative magnitude of each DDI.
• the PBPK model was applied to simulate the interaction potential of multiple-dose RVT- 1201 (600 mg BI D).
• the simulated combined induction and competitive inhibition of CYP2B6 was not predicted to be clinically significant.
• the simulated bupropion C max and AUC 0-inf geometric mean ratios under these conditions were 0.97 and 0.95, respectively.
• the simulated combined induction and competitive inhibition of CYP3A4 was categorized as 'weak' induction ( ⁇ 1.25-fold; ⁇ 2-fold change from baseline).
• Midazolam C max and AUC 0-inf ratios under steady- state RVT-1201 conditions were 0.73 and 0.73, respectively (1.37-fold change from baseline).
• RVT-1201 (AKA KAR5585, rodatristat ethyl) is a small molecule pro-drug that is rapidly hydrolyzed to KAR5417 (AKA KC0035, rodatristat), a potent tryptophan hydroxylate 1 (TPH1) inhibitor that reduces peripheral serotonin (5-hydroxytryptamine [5-HT]) levels in the gut mucosa, lung, and serum in animal models of pulmonary arterial hypertension.
• TPH1 tryptophan hydroxylate 1
• RVT-1201 is rapidly metabolized to form the active species KAR5417, which was the primary circulating species in a rat mass balance study (KRS-01), which is supported by human in vitro (XT184028) and clinical data (Clinical Study KAR5585-101, Clinical Study RVT-1201-1001).
• RVT-1201 is a Biopharmaceutics Classification System (BCS) Class II or IV molecule with in vitro permeability consistent with oral bioavailability, which has been evaluated in a Phase 1 single ascending dose (SAD)/multiple ascending dose (MAD) study using a simple immediate release (IR) drug-in-capsule formulation (Clinical Study KAR5585-101).
• the active pharmaceutical ingredient used in this clinical study was polymorph Form 1.
• An optimized/enhanced oral formulation was developed with a goal to improve patient acceptance, increase the oral bioavailability relative to the IR capsule formulation to facilitate a dose reduction, reduce inter-subject variability and to optimize a formulation process suitable for larger scale manufacture.
• An oral IR tablet formulation and 2 spray-dried dispersion suspensions using polymorph Form 3 were investigated in a second clinical study (Clinical Study RVT-1201-1001). The purpose of this study was to assess the performance of selected formulations following oral administration to healthy subjects.
• RVT-1201-1001 was a single and repeat dose study of RVT-1201 in healthy subjects to evaluate the pharmacokinetic profile of RVT-1201 and its active metabolite KAR5417.
• a single oral dose of 400 mg RVT-120 was administered as an oral powder in Regimen A and B, and as immediate release tablets in Regimen C, to 9 healthy male subjects.
• a single 1200 mg dose as immediate release tablets was administered in Regimen D.
• RVT-1201 Following oral administration in the fed state, RVT-1201 was well absorbed and peak plasma levels were achieved after a median time of 2.5 h. RVT-1201 plasma concentration was variable between subjects, and appeared to decline in an approximately mono-exponential manner (log scale), with an average geometric mean plasma terminal t 1/2 of 5.2 h after 400 mg BID dosing (Clinical Studies RVT-1201-1001 and KAR5585-101).
• the planned clinical dose schedule of RVT-1201 in ELEVATE2 is up to 600 mg BID.
• the twice daily dose schedule is expected to result in minimal accumulation of RVT-1201 ( ⁇ 1.5-fold) after multiple dosing due to the elimination half-life of the drug.
• the geometric mean apparent clearance was 900 L/h after oral administration in Regimen C of Clinical Study RVT-1201-1001. Elimination of RVT-1201 was rapid, and primarily facilitated by hydrolysis to KAR5417. Formation of KAR5417 was attributed to de-esterification of RVT-1201.
• KAR5417 is rapidly formed after oral administration of RVT-1201.
• the median T max of KAR5417 in Regimen C of Clinical Study RVT-1201-1001 (400 mg single dose) was 3.50 h.
• the geometric mean C max of KAR5417 (517 ng/mL) was approximately 5-fold greater than the C max of RVT-1201.
• the geometric mean plasma terminal ti/2of KAR5417 was 12.3 h, indicating that KAR5417 pharmacokinetics are elimination rate limited.
• RVT-1201 and KAR5417 data from this cohort were used to develop the RVT-1201 absorption, and RVT-1201 and KAR5417 distribution and elimination components of the PBPK model.
• Clinical Study KAR5585-101 was a randomized, double blind, placebo-controlled, Phase 1, first-in-human study to characterize the pharmacokinetics of single and multiple ascending doses of RVT-1201 in healthy subjects.
• RVT- 1201 and KAR5417 plasma concentration data on Day 1, 7 and 14 of 400 mg BID administration in fed subjects were used to support verification of the PBPK model.
• multiple dose RVT-1201 and KAR5417 plasma concentration data on Day 1, 7 and 14 of 400 mg or 800 mg BID administration in fed subjects in Clinical Study RVT-1201-1001 were also used to support model verification.
• RVT-1201 and KAR5417 In vitro inhibition studies indicated a potential for RVT-1201 and KAR5417 to inhibit specific CYP isoforms (CYP2B6, CYP2C8 (RVT-1201 only), CYP3A4) (XT155056) and drug transporters (P-gp (RVT-1201 only), OATP1B1/3) (XT-158039).
• mRNA induction of CYP isoforms (CYP2B6, CYP3A4) by RVT-1201 and KAR5417 was also observed in vitro (XT153040). Therefore, development and verification of a PBPK model for KAR5585 and KAR5417 was performed to support investigation of DDI risk in vivo.
• RVT-1201 600 mg BID
• a PBPK model was developed to predict in vivo human RVT-1201 and KAR5417 PK, based on available or simulator-predicted physicochemical, in vitro and clinical data. Model development, verification and application are summarized in the following.
• Model development was completed using RVT-1201 and KAR5417 plasma concentration data after a 400 mg single dose of RVT-1201 as an immediate release tablet in Regimen C of Clinical Study RVT-1201-1001. The following steps were applied in developing the PBPK model.
• RVT-1201 and KAR5417 systemic distribution were described by a minimal PBPK model
• RVT-1201 T Iag and k a were estimated based on the mean plasma concentration data from Regimen C of Clinical Study RVT-1201-1001
• the Simulator estimate of RVT-1201 CL out was optimized to approximate overall mean 11/2 of RVT-1201
• RVT-1201 clearance, and KAR5417 formation were assigned to a cytosolic enzyme mediated process (initial estimate of RVT-1201 CL int was based on liver S9 data and scaled up 6.5-fold to result in sufficient KAR5417 formation)
• RVT-1201 volume of distribution parameters were re-estimated after change from CLPO to cytosolic Clint
• KAR5417 volume of distribution parameters were initially set equal to those for
• RVT-1201 further refinement of deep distribution compartment volume was required to reproduce the observed PK profile from Regimen C of RVT-1201-Study RVT-1201- 1001
• KAR5417 CLPO was optimized to reproduce the observed PK profile from Regimen C of Study RVT-1201-1001
• RVT-1201 and KAR5417 induction of CYP2B6 and CYP3A4 was incorporated in the model based on the in vitro induction of mRNA in human hepatocytes in incubations containing 0.1, 0.3, 1, 3, 10 or 20 ⁇ M RVT-1201 or KAR5417
• the PBPK model was applied to simulate the DDI potential of RVT-1201 and KAR5417 (after steady-state dosing of RVT-1201 600 mg BID) for the following DDIs as a perpetrator.
• Simulated DDI magnitude was summarized by population simulated geometric mean C max and AUC 0-inf ratios of the probe substrate.
• RVT-1201 The metabolic stability of RVT-1201 was measured in vitro in hepatocytes, liver microsomes, lung microsomes, intestinal S9, lung S9, liver S9 and whole blood.
• RVT-1201 was rapidly metabolized to form KAR5417, with ⁇ 5% remaining after a 2 h incubation.
• ⁇ 5% RVT-1201 remained after 2 h incubation in the same study. Therefore, RVT-1201 metabolism (and KAR5417 formation) are not dependent on oxidative or conjugative enzymatic processes.
• KAR5417 Formation of KAR5417 from RVT-1201 is a de-esterification process, which implicates an esterase or esterases as the major mechanism.
• the enzyme(s) responsible for RVT-1201 metabolism to form KAR5417 has not been identified but are considered to be carboxylesterase(s).
• RVT-1201 metabolism and KAR5417 formation were investigated in rat and human whole blood(XT184028). Complete loss of RVT- 1201 was observed in rat blood after incubation of 2 ⁇ M RVT-1201 for 15 min. Complete conversion to KAR5417 was observed in these samples. However, in human whole blood incubations, no loss of RVT-1201 was observed.
• the intrinsic clearance of RVT-1210 in liver S9 fractions was 20 ⁇ L/min/mg protein.
• RVT-1201 and KAR5417 were investigated in vitro (XT158039, XT155056, XT153040).
• the competitive inhibition of specific transporters was investigated for RVT-1201 and KAR5417 in transporter-expressing in vitro systems (XT158039).
• Inhibition of P-gp was evaluated using a Caco-2 cell line with digoxin as probe substrate.
• Inhibition of OATP1B1 and OATP1B3 was evaluated using a HEK293 cell line expressing these transporters with estradiol- 17 ⁇ -glucuronide as probe substrate.
• inhibition of other transporters was also investigated (BCRP, OAT1, OAT3, OCT2, MATE1, MATE2-K).
• RVT-1201 and KAR5417 were investigated for RVT-1201 and KAR5417 in human liver microsomes (HLM) (XT155056).
• HLM human liver microsomes
• CYP1A2, CYP2B6, CYP2C8, CYP2C9, CYP2D6, CYP3A4, CYP3A5 were determined for RVT-1201 IC50 estimates for CYP2B6, CYP2C8 and CYP3A4 only.
• KAR5417 competitively inhibited CYP2C8 only.
• substrate concentration and Km were used to estimate RVT-1201 and KAR5417 Ki.
• CYP1A2, CYP2B6, CYP3A4 The induction of specific CYP isoforms (CYP1A2, CYP2B6, CYP3A4) was investigated for RVT-1201 and KAR5417 in human hepatocytes (HH) (XT153040). RVT-1201 and KAR5417 induction of CYP2B6 and CYP3A4 mRNA was observed in these in vitro experiments. CYP2B6 and CYP3A4 mRNA induction by RVT-1201 and KAR5417 (Emax and EC50) were used to estimate the PBPK model parameters Ind max and Ind C50 .
• Indcso is equal to EC 50 , the concentration of inducer that supports half maximal induction of the CYP isoform (estimated by a sigmoid three parameter fit to in vitro concentration-dependent mRNA induction data).
• the reported Emax for RVT-1201 and KAR5417 was estimated by sigmoid three parameter fit to in vitro concentration-dependent mRNA induction data. Baseline activity was set equal to zero, rather than one, therefore reported E m ax was increased by adding one to each value to estimate I ndmax.
• CYP2B6 induction data was used in the PBPK model as reported.
• CYP3A4 induction data was scaled based on the maximum induction by rifampin (at 20 ⁇ M). Scaling of CYP3A4 induction using rifampin data from the same system leverages the extensive literature on rifampin induction in vitro and in vivo and allows adjustment of in vitro induction data based on the relative performance of rifampin in each in vitro incubation, and the empirical relationship between rifampin induction of CYP3A4 in vitro and in vivo.
• Microsomal protein binding (fumic) is used to adjust for the impact of protein binding on intrinsic clearance and inhibition potency in in vivo experiments. Fumic values can be measured in vivo or predicted within the Simcyp Simulator. This relationship is summarized in Equation (2), where [P]mic is the microsomal protein concentration (mg/mL) used in the in vitro incubation.
• Equation (2) ⁇ umic 1/[([P]mic x 10 0.646 * logP 2 ⁇ 236 ) + 1]
• Fuinc Hepatocyte protein binding
• the PBPK model was then applied to predict the impact of RVT-1201 and KAR5417, as inducers (RVT-1201 and KAR5417) and competitive inhibitor (RVT-1201), on the PK of sensitive substrates of CYP2B6 (bupropion) and CYP3A4 (midazolam), the impact of KAR5417 competitive inhibition on the PK of sensitive substrates of CYP2C8 (rosiglitazone), the impact of RVT-1201 on the PK of sensitive substrates of P-gp (digoxin) and the impact of RVT-1201 and KAR5417 on the PK of sensitive substrates of OATP1B1/3 (rosuvastatin).
• a PBPK model was developed, which accurately simulated the observed plasma concentration of RVT-1201 and KAR5417 after single and multiple oral doses of RVT-1201 (400 mg BID, 800 mg BID).
• RVT-1201 and KAR5417 are weak concentration-dependent inducers of CYP2B6 and CYPP3A4 mRNA in vitro.
• the PBPK model was applied to simulate DDI potential when RVT-1201, dosed to steady state (600 mg BID), is co-administered with a single dose of a sensitive probe substrate of CYP2B6 or CYP3A4.
• RVT-1201 and KAR5417 were weak competitive inhibitors of CYP2B6, CYP2C8, CYP3A4, P-gp (RVT-1201 only) and OATP1B1/3 in vitro.
• the PBPK model was also applied to simulate the DDI potential when RVT-1201, dosed to steady state (600 mg BID), is co-administered with a single dose of a sensitive probe substrate of CYP2B6, CYP2C8, CYP3A4, P-gp or OATP1B1/3.
• the PBPK model was developed using physicochemical, in vitro and clinical data collected for RVT-1201 and KAR5417.
• Single dose (400 mg) plasma concentration data (Regimen C of Clinical Study RVT-1201-1001) was used to estimate the distribution parameters of RVT-1210 and KAR5417.
• RVT-1201 and KAR5417 plasma concentration data from this dataset were used to refine estimates of enzymatic clearance of RVT-1201 and oral clearance of KAR5417.
• the PBPK model was verified through application of the model to simulate RVT-1201 and KAR5417 plasma concentration data after a 400 mg BID or 800 mg BID for 14 days (Day 1, 7 and 14) in Clinical Study RVT-1201-1001 (Regimen E and F, respectively).
• 14 day administration of 400 mg BID in Clinical Study KAR5585-101 was used for model verification.
• RVT-1201 T max , C max and AUC were within 0.40 - 1.60-fold, 0.76 - 1.38-fold and 0.71 - 1.58- fold, respectively, of observed RVT-1201 data (the majority (30 of 33 estimates) of simulated summary PK parameters were within 1.5-fold of observed). Based on the performance of the model in simulating these 11 datasets (33 simulated summary PK parameters), the RVT-1201 PBPK model is adequate for the simulation of DDI potential as perpetrator of DDIs.
• the PBPK model was applied to simulate the DDI potential of RVT-1201 and its metabolite KAR5417 as a perpetrator of CYP2B6, CYP2C8, CYP3A4, P-gp and OATP1B1/3- mediated DDIs.
• the simulated DDI potential of RVT-1201 as an inducer of CYP2B6 was below the lower threshold of 'weak' ( ⁇ 1.25-fold; ⁇ 2-fold change from baseline, or exposure ratios of >0.50; ⁇ 0.80), based on the estimate of CYP2B6 induction potential (in vitro induction of CYP2B6 mRNA).
• a higher threshold of 'weak' ⁇ 1.25-fold; ⁇ 2-fold change from baseline, or exposure ratios of >0.50; ⁇ 0.80
• CYP2B6 induction potential in vitro induction of CYP2B6 mRNA.
• no DDI is predicted with sensitive substrates of CYP2B6.
• Induction of CYP mRNA is considered a more sensitive marker of induction than in vitro activity (Fahmi et al., 2010).
• induction simulations based on mRNA data may be considered the 'worst-case' scenario of CYP2B6-mediated DDI liability of RVT-1201, and as such, are expected to represent an over-prediction of the clinical induction potential of RVT-1201 and KAR5417.
• the simulated DDI potential of RVT-1201 as an inducer of CYP3A4 was at the lower threshold of 'weak' ( ⁇ 1.25-fold; ⁇ 2-fold), based on the estimate of CYP3A4 induction potential (in vitro induction of CYP3A4 mRNA).
• a weak DDI is predicted with sensitive substrates of CYP3A4.
• Induction of CYP mRNA is considered a more sensitive marker of induction than in vitro activity (Fahmi et al., 2010). Therefore, induction simulations based on mRNA data may be considered the 'worst-case' scenario of CYP3A4-mediated DDI liability of RVT-1201, and as such, are expected to represent an over-prediction of the clinical induction potential of RVT-1201 and KAR5417.
• the PBPK model incorporated a rifampin-scaled estimate of Indmax which is expected to minimize the over-prediction associated with mRNA- based induction parameters.
• the simulated DDI potential of RVT-1201 as a competitive inhibitor of CYP2C8 was below the lower threshold of 'weak' ( ⁇ 1.25-fold; ⁇ 2-fold), based on the estimate of CYP2C8 inhibition potential (in vitro Ki).
• 'weak' ⁇ 1.25-fold; ⁇ 2-fold
• in vitro Ki the estimate of CYP2C8 inhibition potential
• the simulated DDI potential of RVT-1201 as a competitive inhibitor of P-gp was below the lower threshold of 'weak' ( ⁇ 1.25-fold; ⁇ 2-fold), based on the estimate of P-gp inhibition potential (invitro Ki).
• 'weak' ⁇ 1.25-fold; ⁇ 2-fold
• P-gp inhibition potential invitro Ki
• the simulated DDI potential of RVT-1201 as a competitive inhibitor of OATP1B1/3 was below the lower threshold of 'weak' ( ⁇ 1.25-fold; ⁇ 2-fold), based on the estimate of OATP1B1/3 inhibition potential (in vitro Ki).
• no DDI is predicted with sensitive substrates of OATP1B1/3.
• no DDI with sensitive substrates of OATP1B1/3 is predicted.
• a PBPK model was developed which described the observed plasma concentration data of RVT-1201 and KAR5417 after oral administration of single or multiple (BID) doses between 400 and 800 mg.
• This model was then applied to simulate the DDI potential of RVT-1201 and its metabolite KAR5417, as perpetrator of CYP2B6, CYP2C8, CYP3A4, P-gp or OATP1B1/3 DDIs.
• a 'weak' potential for CYP3A4-mediated DDIs was the only interaction predicted by the PBPK model.
• RVT-1201 is not predicted to perpetrate DDIs with sensitive substrates of CYP2B6, CYP2C8, P-gp or OATP1B1/3.
• CL out elimination rate clearance (VSAC) CL perm a clearance term defining the permeability through the enterocyte CL PO oral plasma clearance CL renal renal clearance
• ISEF inter-system extrapolation factor k a first order absorption rate constant kg kilograms K i enzyme/transporter competitive inhibition constant (concentration of inhibitor associated with half maximal inhibition)
• V r ratio of the cell and incubation volume V SAC volume of single adjusting compartment

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