WO2019002441A1

WO2019002441A1 - Chemical compounds

Info

Publication number: WO2019002441A1
Application number: PCT/EP2018/067370
Authority: WO
Inventors: James Stewart Scott; Thomas Anthony Hunt; Bernard Christophe Barlaam
Original assignee: Astrazeneca Ab
Priority date: 2017-06-29
Filing date: 2018-06-28
Publication date: 2019-01-03

Abstract

The specification relates to compounds of Formula (I) and to pharmaceutically acceptable salts thereof, to processes and intermediates used for their preparation, to pharmaceutical compositions containing them and to their use in the treatment of cell proliferative disorders.

Description

CHEMICAL COMPOUNDS

This specification relates to certain indazole compounds and pharmaceutically acceptable salts thereof that selectively down-regulate the estrogen receptor and possess anti-cancer activity. This specification also relates to use of said indazole compounds and pharmaceutically acceptable salts thereof in methods of treatment of the human or animal body, for example in prevention or treatment of cancer. This specification also relates to processes and intermediate compounds involved in the preparation of said indazole compounds and to pharmaceutical compositions containing them.

Estrogen receptor alpha (ERa, ESR1, NR3A) and estrogen receptor beta (ER , ESR2, NR3b) are steroid hormone receptors which are members of the large nuclear receptor family. Structured similarly to all nuclear receptors, ERa is composed of six functional domains (named A-F) (Dahlman- Wright, et al., Pharmacol. Rev., 2006, 58:773- 781) and is classified as a ligand-dependent transcription factor because after its association with the specific ligand, (the female sex steroid hormone 17b estradiol (E2)), the complex binds to genomic sequences, named Estrogen Receptor Elements (ERE) and interacts with co-regulators to modulate the transcription of target genes. The ERa gene is located on 6q25.1 and encodes a 595 AA protein and multiple isoforms can be produced due to alternative splicing and translational start sites. In addition to the DNA binding domain (Domain C) and the ligand binding domain (Domain E) the receptor contains a N- terminal (A/B) domain, a hinge (D) domain that links the C and E domains and a C- terminal extension (F domain). While the C and E domains of ERa and ER are quite conserved (96% and 55%> amino acid identity respectively) conservation of the A/B, D and F domains is poor (below 30% amino acid identity). Both receptors are involved in the regulation and development of the female reproductive tract and in addition play roles in the central nervous system, cardiovascular system and in bone metabolism. The genomic action of ERs occurs in the nucleus of the cell when the receptor binds EREs directly (direct activation or classical pathway) or indirectly (indirect activation or non-classical pathway). In the absence of ligand, ERs are associated with heat shock proteins, Hsp90 and Hsp70, and the associated chaperone machinery stabilizes the ligand binding domain (LBD) making it accessible to ligand. Liganded ER dissociates from the heat shock proteins leading to a conformational change in the receptor that allows dimerisation, DNA binding, interaction with co-activators or co-repressors and modulation of target gene expression. In the non-classical pathway, AP-1 and Sp-1 are alternative regulatory DNA sequences used by both isoforms of the receptor to modulate gene expression. In this example, ER does not interact directly with DNA but through associations with other DNA bound transcription factors e.g. c-Jun or c-Fos (Kushner et al, Pure Applied Chemistry 2003, 75: 1757-1769). The precise mechanism whereby ER affects gene transcription is poorly understood but appears to be mediated by numerous nuclear factors that are recruited by the DNA bound receptor. The recruitment of co-regulators is primarily mediated by two protein surfaces, AF2 and AF1 which are located in E-domain and the A/B domain respectively. AF1 is regulated by growth factors and its activity depends on the cellular and promoter environment whereas AF2 is entirely dependent on ligand binding for activity. Although the two domains can act independently, maximal ER transcriptional activity is achieved through synergistic interactions via the two domains (Tzukerman, et al, Mol. Endocrinology, 1994, 8:21-30). Although ERs are considered transcription factors they can also act through non-genomic mechanisms as evidenced by rapid ER effects in tissues following E2 administration in a timescale that is considered too fast for a genomic action. It is still unclear if receptors responsible for the rapid actions of estrogen are the same nuclear ERs or distinct G-protein coupled steroid receptors (Warner, et al, Steroids 2006 71:91-95) but an increasing number of E2 induced pathways have been identified e.g. MAPK/ER pathway and activation of endothelial nitric oxide synthase and PI3K/Akt pathway. In addition to ligand dependent pathways, ERa has been shown to have ligand independent activity through AF-1 which has been associated with stimulation of MAPK through growth factor signalling e.g. insulin like growth factor 1 (IGF-1) and epidermal growth factor (EGF). Activity of AF-1 is dependent on

phosphorylation of Serl 18 and an example of cross-talk between ER and growth factor signalling is the phosphorylation of Ser 118 by MAPK in response to growth factors such as IGF-1 and EGF (Kato, et al, Science, 1995, 270: 1491-1494). A large number of structurally distinct compounds have been shown to bind to ER. Some compounds such as endogenous ligand E2, act as receptor agonists whereas others competitively inhibit E2 binding and act as receptor antagonists. These compounds can be divided into 2 classes depending on their functional effects. Selective estrogen receptor modulators (SERMs) such as tamoxifen have the ability to act as both receptor agonists and antagonists depending on the cellular and promoter context as well as the ER isoform targeted. For example tamoxifen acts as an antagonist in breast but acts as a partial agonist in bone, the cardiovascular system and uterus. All SERMs appear to act as AF2 antagonists and derive their partial agonist characteristics through AFl . A second group, fulvestrant being an example, are classified as full antagonists and are capable of blocking estrogen activity via the complete inhibition of AFl and AF2 domains through induction of a unique conformation change in the ligand binding domain (LBD) on compound binding which results in complete abrogation of the interaction between helix 12 and the remainder of the LBD, blocking co-factor recruitment (Wakeling, et al, Cancer Res., 1991, 51 :3867-3873; Pike, et al, Structure, 2001, 9: 145-153).

Intracellular levels of ERa are down-regulated in the presence of E2 through the ubiquitin/proteosome (Ub/26S) pathway. Polyubiquitinylation of liganded ERa is catalysed by at least three enzymes; the ubiquitin-activating enzyme El activated ubiquitin is conjugated by E2 with lysine residues through an isopeptide bond by E3 ubiquitin ligase and polyubiquitinated ERa is then directed to the proteosome for degradation. Although ER-dependent transcription regulation and proteosome -mediated degradation of ER are linked (Lonard, et al, Mol. Cell, 2000 5:939-948), transcription in itself is not required for ERa degradation and assembly of the transcription initiation complex is sufficient to target ERa for nuclear proteosomal degradation. This E2 induced degradation process is believed to necessary for its ability to rapidly activate transcription in response to requirements for cell proliferation, differentiation and metabolism (Stenoien, et al., Mol. Cell Biol., 2001, 2J_:4404-4412). Fulvestrant is also classified as a selective estrogen receptor down- regulator (SERD), a subset of antagonists that can also induce rapid down-regulation of ERa via the 26S proteosomal pathway. In contrast a SERM such as tamoxifen can increase ERa levels although the effect on transcription is similar to that seen for a SERD. Approximately 70% of breast cancers express ER and/or progesterone receptors implying the hormone dependence of these tumour cells for growth. Other cancers such as ovarian and endometrial are also thought to be dependent on ERa signalling for growth. Therapies for such patients can inhibit ER signalling either by antagonising ligand binding to ER e.g. tamoxifen which is used to treat early and advanced ER positive breast cancer in both pre and post menopausal setting; antagonising and down-regulating ERa e.g.

fulvestrant which is used to treat breast cancer in women which have progressed despite therapy with tamoxifen or aromatase inhibitors; or blocking estrogen synthesis e.g.

aromatase inhibitors which are used to treat early and advanced ER positive breast cancer. Although these therapies have had an enormously positive impact on breast cancer treatment, a considerable number of patients whose tumours express ER display de novo resistance to existing ER therapies or develop resistance to these therapies over time. Several distinct mechanisms have been described to explain resistance to first-time tamoxifen therapy which mainly involve the switch from tamoxifen acting as an antagonist to an agonist, either through the lower affinity of certain co-factors binding to the tamoxifen-ERa complex being off-set by over-expression of these co-factors, or through the formation of secondary sites that facilitate the interaction of the tamoxifen-ERa complex with co-factors that normally do not bind to the complex. Resistance could therefore arise as a result of the outgrowth of cells expressing specific co-factors that drive the tamoxifen-ERa activity. There is also the possibility that other growth factor signalling pathways directly activate the ER receptor or co-activators to drive cell proliferation independently of ligand signalling.

More recently, mutations in ESR1 have been identified as a possible resistance mechanism in metastatic ER-positive patient derived tumour samples and patient-derived xenograft models (PDX) at frequencies varying from 17-25%. These mutations are predominantly, but not exclusively, in the ligand-binding domain leading to mutated functional proteins; examples of the amino acid changes include Ser463Pro, Val543Glu, Leu536Arg, Tyr537Ser, Tyr537Asn and Asp538Gly, with changes at amino acid 537 and 538 constituting the majority of the changes currently described. These mutations have been undetected previously in the genomes from primary breast samples characterised in the Cancer Genome Atlas database. Of 390 primary breast cancer samples positive for ER expression not a single mutation was detected in ESR1 (Cancer Genome Atlas Network, 2012 Nature 490: 61-70). The ligand binding domain mutations are thought to have developed as a resistance response to aromatase inhibitor endocrine therapies as these mutant receptors show basal transcriptional activity in the absence of estradiol. The crystal structure of ER, mutated at amino acids 537 and 538, showed that both mutants favoured the agonist conformation of ER by shifting the position of helix 12 to allow co-activator recruitment and thereby mimicking agonist activated wild type ER. Published data has shown that endocrine therapies such as tamoxifen and fulvestrant can still bind to ER mutant and inhibit transcriptional activation to some extent and that fulvestrant is capable of degrading Try537Ser but that higher doses may be needed for full receptor inhibition (Toy et al, Nat. Genetics 2013. 45: 1439-1445; Robinson et al, Nat. Genetics 2013, 45: 144601451; Li, S. et al. Cell Rep. 4, 1116-1130 (2013). It is therefore feasible that certain compounds of the Formula (I) or pharmaceutically acceptable salts thereof (as described hereinafter) will be capable of down-regulating and antagonising mutant ER although it is not known at this stage whether ESR1 mutations are associated with an altered clinical outcome.

Regardless of which resistance mechanism or combination of mechanisms takes place, many are still reliant on ER-dependent activities and removal of the receptor through a SERD mechanism offers the best way of removing the ERa receptor from the cell.

Fulvestrant is currently the only SERD approved for clinical use, yet despite its mechanistic properties, the pharmacological properties of the drug have limited its efficacy due to the current limitation of a 500mg monthly dose which results in less than 50% turnover of the receptor in patient samples compared to the complete down-regulation of the receptor seen in in vitro breast cell line experiments (Wardell, et al., Biochem. Pharm., 2011, 82:122-130). Hence there is a need for new ER targeting agents that have the required pharmaceutical properties and SERD mechanism to provide enhanced benefit in the early, metastatic and acquired resistance setting.

The compounds of the specification have been found to possess potent anti-tumour activity, being useful in inhibiting the uncontrolled cellular proliferation which arises from malignant disease. The compounds of the specification provide an anti-tumour effect by, as a minimum, acting as SERDs. For example, the compounds of the specification may exhibit anti -tumour activity via the ability to down-regulate the estrogen receptor in a number of different breast cancer cell-lines, for example against the MCF-7, CAMA-1, BT474 and/or MDA-MB-134 breast cancer cell-lines. Such compounds may be expected to be more suitable as therapeutic agents, particularly for the treatment of cancer.

The compounds of the specification may also exhibit advantageous physical properties (for example, lower lipophilicity, higher aqueous solubility, higher permeability, lower plasma protein binding, and/or greater chemical stability), and/or favourable toxicity profiles (for example a decreased activity at hERG), and/or favourable metabolic or pharmacokinetic profiles, in comparison with other known SERDs. Such compounds may therefore be especially suitable as therapeutic agents, particularly for the treatment of cancer.

According to one aspect of the specification there is provided a compound of Formula (I):

wherein:

A is CR⁴ or N;

R¹ is H, F or OMe;

R² is H, F or CH₂OH;

R³ is H or F; and R⁴ is H or F;

or a pharmaceutically acceptable salt thereof.

This specification also describes pharmaceutical compositions which comprise a compound of Formula (I), or a pharmaceutically acceptable salt thereof, in association with a pharmaceutically acceptable excipient.

This specification also describes a compound of Formula (I), or a pharmaceutically acceptable salt thereof, for use as a medicament.

This specification also describes a compound of Formula (I), or a pharmaceutically acceptable salt thereof, for use in the treatment of cancer.

This specification also describes combinations of a compound of Formula (I), or a pharmaceutically acceptable salt thereof, with another anti-tumour agent, for use in the treatment of cancer.

Further aspects of the specification will be apparent to one skilled in the art from reading this specification.

In one embodiment there is provided a compound of Formula (I) as defined above.

In one embodiment there is provided a pharmaceutically acceptable salt of a compound of Formula (I).

In a further embodiment there is provided a compound of the Formula (IA):

(IA)

wherein:

A is CR⁴ or N; R¹ is F or OMe;

R² is H, F or CH₂OH;

R³ is H or F; and

R⁴ is H or F;

or a pharmaceutically acceptable salt thereof.

In a further embodiment A is CR⁴.

In one embodiment A is N.

In one embodiment A is CH.

In one embodiment R¹ is F.

In one embodiment R¹ is OMe.

In one embodiment R² is H.

In one embodiment R² is F.

In one embodiment R² is CH₂OH.

In one embodiment R³ is H.

In one embodiment R³ is F.

In one embodiment A is N; R¹ is H or F; R² is H, F or CH₂OH; and R³ is H or F; or a pharmaceutically acceptable salt thereof.

In one embodiment A is N; R¹ is H or F; R² is H, F or CH₂OH; and R³ is H; or a pharmaceutically acceptable salt thereof.

In one embodiment A is N; R¹ is H; R² is H, F or CH₂OH; and R³ is H or F; or a pharmaceutically acceptable salt thereof.

In one embodiment A is N; R¹ is H or F; R² is F; and R³ is H or F; or a

pharmaceutically acceptable salt thereof.

In one embodiment A is N; R¹ is H; R² is H, F or CH₂OH; and R³ is H; or a pharmaceutically acceptable salt thereof.

In one embodiment A is N; R¹ is H or F; R² is F; and R³ is H; or a pharmaceutically acceptable salt thereof.

In one embodiment A is N; R¹ is H or F; R² is F; and R³ is F; or a pharmaceutically acceptable salt thereof.

In one embodiment A is CH or C-F; R¹ is H, F or OMe; R² is H, F or CH₂OH; and R³ is H or F; or a pharmaceutically acceptable salt thereof. In one embodiment A is CH or C-F; R¹ is H or OMe; R² is H, F or CH₂OH; and R³ is H; or a pharmaceutically acceptable salt thereof.

In one embodiment A is CH; R¹ is OMe; R² is H, F or CH₂OH; and R³ is H or F; or a pharmaceutically acceptable salt thereof.

In one embodiment A is CH; R¹ is OMe; R² is H, F or CH2OH; and R³ is H; or a pharmaceutically acceptable salt thereof.

In a further aspect there is provided the compound of Formula (IZ):

(IZ)

wherein:

A is CR⁴ or N;

R¹ is H, F or OMe;

R² is H, F or CH₂OH;

R³ is H or F; and

R⁴ is H or F;

or a pharmaceutically acceptable salt thereof.

In a further embodiment there is provided the compound of Formula (IZ) or a pharmaceutically acceptable salt thereof wherein the stereochemistry at the 6-position of the pyrazolo[4,3-f]isoquinoline ring is S.

In a further embodiment there is provided the compound of Formula (IZ) or a pharmaceutically acceptable salt thereof wherein the stereochemistry at the 6-position of the pyrazolo[4,3-f]isoquinoline ring is R. In a further embodiment there is provided the compound of Formula (IZ) or a pharmaceutically acceptable salt thereof wherein the stereochemistry at the 8-position of the pyrazolo[4,3-f]isoquinoline ring is S.

In a further embodiment there is provided the compound of Formula (IZ) or a pharmaceutically acceptable salt thereof wherein the stereochemistry at the 8-position of the pyrazolo[4,3-f]isoquinoline ring is R.

In one embodiment there is provided a compound of Formula (I), wherein the compound is selected from the group consisting of:

N-((S)-l-(3-fluoropropyl)pyrrolidin-3-yl)-6-((6S,8R)-8-methyl-7-(2,2,2 rifluoroethyl)-

6,7,8,9-tetrahydro-3H-pyrazolo[4,3-fJisoquinolin-6-yl)pyridin-3-amine;

6-((6S,8R)-7-(2,2-difluoroethyl)-8-methyl-6,7,8,9-tetrahydro-3H-pyrazolo[4,3- fJisoquinolin-6-yl)-N-((S)-l-(3-fluoropropyl)pyrrolidin-3-yl)pyridin-3-amine; and

N-((S)-l-(3-fiuoropropyl)pyrrolidin-3-yl)-6-((6S,8R)-l-fluoro-8-methyl-7-(2,2,2- trifluoroethyl)-6,7,8,9-tetrahydro-3H-pyrazolo[4,3-f]isoquinolin-6-yl)pyridin-3-amine; or a pharmaceutically acceptable salt thereof.

In one embodiment there is provided a compound of Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, wherein the compound is selected from any of the Examples in the specification. A further feature is any of the embodiments described in the specification with the proviso that any of the specific Examples are individually disclaimed. A further feature is any of the embodiments described in the specification with the proviso that any one or more of the compounds selected from the above list of examples of compounds of the specification are individually disclaimed.

The compounds of Formula (I), (IA) or (IZ) have two or more chiral centres and it will be recognised that the compounds of Formula (I), (IA) or (IZ) may be prepared, isolated and/or supplied with or without the presence, in addition, of one or more of the other possible enantiomeric and/or diastereomeric isomers of the compounds of Formula (I), (IA) or (IZ) in any relative proportions. The preparation of enantioenriched/ enantiopure and/or diastereoenriched/ diastereopure compounds may be carried out by standard techniques of organic chemistry that are well known in the art, for example by synthesis from enantioenriched or enantiopure starting materials, use of an appropriate enantioenriched or enantiopure catalyst during synthesis, and/or by resolution of a racemic or partially enriched mixture of stereoisomers, for example via chiral chromatography.

For use in a pharmaceutical context it may be preferable to provide a compound of Formula (I), (IA) or (IZ) or a pharmaceutically acceptable salt thereof without large amounts of the other stereoisomeric forms being present.

Accordingly, in one embodiment there is provided a composition comprising a compound of Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, optionally together with one or more of the other stereoisomeric forms of the compound of Formula (I), (IA) or (IZ), or pharmaceutically acceptable salt thereof, wherein the compound of Formula (I), (IA) or (IZ), or pharmaceutically acceptable salt thereof is present within the composition with a diastereomeric excess (%de) of > 90%.

In a further embodiment the %de in the above-mentioned composition is > 95%.

In a further embodiment the %de in the above-mentioned composition is > 98%.

In a further embodiment the %de in the above-mentioned composition is > 99%.

In a further embodiment there is provided a composition comprising a compound of Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, optionally together with one or more of the other stereoisomeric forms of the compound of Formula (I), (IA) or (IZ), or pharmaceutically acceptable salt thereof, wherein the compound of Formula (I), (IA) or (IZ), or pharmaceutically acceptable salt thereof is present within the composition with an enantiomeric excess (%ee) of > 90%.

In a further embodiment the %ee in the above-mentioned composition is > 95%.

In a further embodiment the %ee in the above-mentioned composition is > 98%.

In a further embodiment the %ee in the above-mentioned composition is > 99%.

In a further embodiment there is provided a composition comprising a compound of Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, optionally together with one or more of the other stereoisomeric forms of the compound of Formula (I), (IA) or (IZ), or pharmaceutically acceptable salt thereof, wherein the compound of Formula (I), (IA) or (IZ), or pharmaceutically acceptable salt thereof is present within the composition with an enantiomeric excess (%>ee) of > 90%> and a diastereomeric excess (%>de) of > 90%>. In further embodiments of the above-mentioned composition the %ee and %de may take any combination of values as listed below:

• The %ee is <5% and the %de is≥ 80%.

• The %ee is <5% and the %de is≥ 90%.

• The %ee is <5% and the %de is≥ 95%.

• The %ee is <5% and the %de is≥ 98%.

• The %ee is≥ 95% and the %de is≥ 95%.

• The %ee is≥ 98% and the %de is≥ 98%.

• The %ee is≥ 99% and the %de is≥ 99%.

In a further embodiment there is provided a pharmaceutical composition which comprises a compound of the Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, in association with a pharmaceutically acceptable excipient.

In one embodiment there is provided a pharmaceutical composition which comprises a compound of the Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, in association with a pharmaceutically acceptable excipient, optionally further comprising one or more of the other stereoisomeric forms of the compound of (I) or (IA), or pharmaceutically acceptable salt thereof, wherein the compound of Formula (I), (IA) or (IZ) or pharmaceutically acceptable salt thereof is present within the composition with an enantiomeric excess (%ee) of > 90%.

In a further embodiment the %ee in the above-mentioned composition is > 95%.

In a further embodiment the %ee in the above-mentioned composition is > 98%.

In a further embodiment the %ee in the above-mentioned composition is > 99%.

In one embodiment there is provided a pharmaceutical composition which comprises a compound of the Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, in association with a pharmaceutically acceptable excipient, optionally further comprising one or more of the other stereoisomeric forms of the compound of Formula (I), (IA) or (IZ), or pharmaceutically acceptable salt thereof, wherein the compound of Formula (I), (IA) or (IZ), or pharmaceutically acceptable salt thereof is present within the composition with a diastereomeric excess (%de) of > 90%.

In a further embodiment the %de in the above-mentioned composition is > 95%. In a further embodiment the %de in the above-mentioned composition is > 98%.

In a further embodiment the %de in the above-mentioned composition is > 99%.

In one embodiment there is provided a pharmaceutical composition which comprises a compound of the Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, in association with a pharmaceutically acceptable excipient, optionally further comprising one or more of the other stereoisomeric forms of the compound of Formula (I), (IA) or (IZ), or pharmaceutically acceptable salt thereof, wherein the compound of

Formula (I), (IA) or (IZ), or pharmaceutically acceptable salt thereof is present within the composition with an enantiomeric excess (%ee) of > 90% and a diastereomeric excess (%de) of≥90%.

In further embodiments of the above-mentioned pharmaceutical composition the %ee and %de may take any combination of values as listed below:

• The %ee is≥ 95% and the %de is≥ 95%.

• The %ee is≥ 98% and the %de is≥ 98%.

• The %ee is≥ 99% and the %de is≥ 99%.

The compounds of Formula (I), (IA) or (IZ), and pharmaceutically acceptable salts thereof may be prepared, used or supplied in amorphous form, crystalline form, or semicrystalline form and any given compound of Formula (I), (IA) or (IZ), or

pharmaceutically acceptable salt thereof may be capable of being formed into more than one crystalline / polymorphic form, including hydrated (e.g. hemi-hydrate, a

mono-hydrate, a di-hydrate, a tri-hydrate or other stoichiometry of hydrate) and/or solvated forms. It is to be understood that the present specification encompasses any and all such solid forms of the compound of Formula (I), (IA) or (IZ), and pharmaceutically acceptable salts thereof.

In further embodiments there is provided a compound of Formula (I), (IA) or (IZ), which is obtainable by the methods described in the 'Examples' section hereinafter.

The present specification is intended to include all isotopes of atoms occurring in the present compounds. Isotopes will be understood to include those atoms having the same atomic number but different mass numbers. For example, isotopes of hydrogen include tritium and deuterium. Isotopes of carbon include C and C. Isotopes of nitrogen include ¹⁵N.

A suitable pharmaceutically acceptable salt of a compound of the Formula (I), (IA) or (IZ), is, for example, an acid addition salt. A suitable pharmaceutically acceptable salt of a compound of Formula (I), (IA) or (IZ), may be, for example, an acid-addition salt of a compound of the Formula (I), (IA) or (IZ).

A further suitable pharmaceutically acceptable salt of a compound of the Formula (I), (IA) or (IZ), is, for example, a salt formed within the human or animal body after administration of a compound of the Formula (I), (IA) or (IZ)„ to said human or animal body.

The compound of Formula (I), (IA) or (IZ), or pharmaceutically acceptable salt thereof may be prepared as a co-crystal solid form. It is to be understood that a

pharmaceutically acceptable co-crystal of a compound of the Formula (I), (IA) or (IZ), or pharmaceutically acceptable salts thereof, form an aspect of the present specification.

For the avoidance of doubt it is to be understood that where in this specification a group is qualified by 'hereinbefore defined' or 'defined herein' the said group

encompasses the first occurring and broadest definition as well as each and all of the alternative definitions for that group.

Another aspect of the present specification provides a process for preparing a compound of the Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof. A suitable process is illustrated by the following representative process variants in which, unless otherwise stated, A and R¹ to R³ have any of the meanings defined hereinbefore. Necessary starting materials may be obtained by standard procedures of organic chemistry. The preparation of such starting materials is described in conjunction with the following representative process variants and within the accompanying Examples. Alternatively, necessary starting materials are obtainable by analogous procedures to those illustrated which are within the ordinary skill of an organic chemist.

Compounds of Formula (I) where R³ is H may be made by, for example:

a) amination of a suitable compound of Formula (II), where L is for example a halogen (such as iodine), or a trifluoromethylsulfonyloxy (triflate) group, with an amine of Formula (IV) using a suitable metal catalyst (for example BrettPhos or RuPhos, and Pd₂(dba)3) in a suitable solvent (for example 1,4-dioxane) in the presence of a suitable base (for example cesium carbonate, sodium tert-butoxide, or LiHMDS) at a suitable temperature (such as 90-130 °C); removal of the protecting group (PG), such as THP, using acid conditions (such as anhydrous HC1 in 1,4-dioxane) at suitable temperature (such as 10-30 °C).

(II) (IV)

b) alkylation of a suitable compound of Formula (VI) with a compound of Formula (VII) where LG is a leaving group (such as halide or mesylate), using mild bases (for example DIPEA) in a suitable solvent (such as DMF or MeCN); removal of the protecting group (PG), such as THP, using acid conditions (such as anhydrous HC1 in 1,4-dioxane) at suitable temperature (such as 10-30 °C).

e) Alkylation of amines of Formula (VIII) with a suitable alkylating group of Formula (IX) (wherein LG can be halide, as bromide, iodide or chloride, or may be some other suitable leaving group, such as mesylate) in a suitable solvent (such as DMF) in the presence of a suitable base (such as DIPEA) at a suitable temperature (such as 10- 30 °C).

(VIII) (IX)

Compounds of formula (II) may be prepared by, for example, reaction of an aniline of Formula (XI) with suitable reagents to effect the construction of an indazole such as inorganic nitrite (such as sodium nitrite) in organic acid (such as propionic acid) at low temperature (typically -20 to 0 °C) or alternatively an acid anhydride (such as acetic anhydride) in the presence of a suitable base (such as potassium acetate) together with organic nitrite (such as isopentyl nitrite) optionally in the presence of a crown ether (such as 18-crown-6) in a suitable solvent (such as chloroform) at a suitable temperature (such as 70 °C).

(XI)

Compounds of formula (XI) may be made by reaction of a compound of formula (XII) with a compound of formula (XIII) under conditions known in the art as suitable for Pictet- Spengler reactions, such as in the presence of acid (such as acetic acid) and in a suitable solvent (for example toluene or water) and a suitable temperature (such as 60 -100 °C).

(XII) (XIII)

Compounds of formula (XII) may be prepared by functional group interconversions known to the art, for example aminations of halides of formula (XIV) from aryl halides (such as bromide) using a protected amine (such as diphenylmethanimine) in the presence of a suitable catalyst and ligand (such as bis(dibenzylideneacetone)palladium(0) and rac- 2,2'- bis(diphenylphosphino)-l,l'-binaphthyl) in the presence of a suitable base (such as sodium tert-butoxide) in a suitable solvent (such as toluene) at a suitable temperature (such as 80- 100 °C).

(XIV)

Compounds of Formula (XIV) may be prepared by:

a) reaction of a compound of formula (XV) with an aldehyde of formula (XVI), in a suitable solvent (for example THF) in the presence of a suitable reducing agent (such as sodium triacetoxyborohydride) and at a suitable temperature (such as 20-30°C);

b) (i) reaction of a compound of formula (XV) with an acid of formula (XVII) under standard amide bond forming conditions (for example in the presence of an amide coupling reagent (such as HATU) and a suitable base (such as triethylamine) in a suitable solvent (such as DMF)), followed by (ii) reduction of the resultant amide bond using a suitable reducing agent (such as borane) in a suitable solvent (such as THF) at a suitable temperature (such as 60-70 °C);

c) reaction of a compound of formula (XV) with a compound of formula (XVIII), wherein LG is a suitable leaving group (for example a halogen atom (such as bromo or chloro) or triflate), in the presence of a suitable base (such as diisopropylethylamine) in a suitable solvent (for example DCM or dioxane) and at a suitable temperature (such as 20-85 °C).

(XV) (XVI) (XVII) (XVIII)

Compounds of formula (XV) may be prepared by a number of methods known to the art for the synthesis of chiral amines notably;

a) Ring opening of sulfami dates of Formula (XIX) according to the scheme shown below.

(XIX) (XV)

Step 1 : Alkylation, e.g. n-butyllithium/THF/-78 °C to 0 °C

Step 2: Removal of protection groups, e.g. anhydrous HC1 in MeOH/DCM, rt.

Compounds of Formula (XII) may be directly prepared by:

a) reaction of a compound of formula (XX) with an aldehyde of formula (XVI), in a suitable solvent (for example THF) in the presence of a suitable reducing agent (such as sodium triacetoxyborohydride) and at a suitable temperature (such as 20-30°C);

b) (i) reaction of a compound of formula (XX) with an acid of formula (XVII) under standard amide bond forming conditions (for example in the presence of an amide coupling reagent (such as HATU) and a suitable base (such as triethylamine) in a suitable solvent (such as DMF)), followed by (ii) reduction of the resultant amide bond using a suitable reducing agent (such as borane) in a suitable solvent (such as THF) at a suitable temperature (such as 60-70 °C);

c) reaction of a compound of formula (XX) with a compound of formula (XIII), wherein LG is a suitable leaving group (for example a halogen atom (such as bromo or chloro) or triflate), in the presence of a suitable base (such as diisopropylethylamme) in a suitable solvent (for example DCM or dioxane) and at a suitable temperature (such as 20-85 °C).

(XX) (XVI) (XVII) (XVIII)

Compounds of Formula (XX) may be prepared through a reaction sequence starting from a protected 3 -bromo-2 -methyl-aniline as shown below.

(XIX) (XX)

Step 1 : Alkylation, e.g. n-butyllithium/THF/-78 °C to rt.

Step 2: Removal of amine protection groups, e.g. anhydrous HC1 in MeOH/DCM, rt. Step 3: Removal of aniline protection groups, e.g. refluxing in hydroxylamine.

Compounds of Formula (V) may be prepared through a sequence involving Pictet- Spengler cyclisation of a boronate ester-containing compound of Formula (XIII) as described above to give a compound of Formula (XXI). A compound of Formula (XXI) can be oxidized to a compound of Formula (V) using a suitable oxidant (such as hydrogen peroxide) in the presence of a suitable base (such as sodium hydroxide) in a suitable solvent (such as THF).

(XXI)

Compounds of Formula (VI) may be prepared through a sequence involving Pictet- Spengler cyclisation of a nitro containing compound of Formula (XIII) as described above to give a compound of Formula (XXII). A compound of Formula (XXII) can be reduced to a compound of Formula (VI) using suitable nitro reduction conditions (such as hydrogenation) in the presence of a suitable catalyst (such as platinum dioxide) in a suitable solvent (such as methanol .

(XXII)

Compounds of Formula (VIII) may be prepared from aryl halides of Formula (II) and tert-butyl 3-aminoazetidine-l-carboxylate using a suitable metal catalyst (for example for example RuPhos or BrettPhos and Pd₂(dba)3) in a suitable solvent (for example 1 ,4- dioxane) in the presence of a suitable base (for example cesium carbonate, sodium tert- butoxide, or LiHMDS) at a suitable temperature (such as 90-130 °C); the Boc protecting group may be subsequently removed using an acid (such as trifluoroacetic acid) in a suitable solvent (such as DCM).

Compounds of Formula (III) may be prepared by:

a) Alkylation reaction between 3-hydroxypyrrolidine and compounds of Formula (IX) where LG for example a halogen or other leaving group (such as mesyl group) in the presence of a suitable base, such as cesium carbonate, in a suitable solvent, such as acetonitrile, at a suitable temperature, such as 120 °C, and in a suitable container, such as a sealed tube.

b) Reductive amination reaction between 3-hydroxypyrrolidine and aldehyde or ketone compounds of Formula (XXIII) in the presence of a suitable reducing reagent, such as sodium triacetoxyborohydride, in a suitable solvent, such as DCM, in a suitable temperature, such as 10-30 °C.

(XXIII) Compounds of Formula (IV) may be prepared by:

a) (i) Alkylation reaction between compound of Formula (XXIV), where PG is a

pretecting group for example Boc, and compounds of Formula (IX) where LG is for example a halogen or other leaving group, such as mesylate, in the presence of a suitable base, such as DIPEA, in a suitable solvent, such as 1 ,4-dioxane, at a suitable temperature, such as 10-30 °C. (ii) Removal of the protection group under suitable conditions, such as acidic conditions for the removal of Boc.

(XXIV)

b) (i)Reductive amination reaction between compounds of Formula (XXIV) and aldehyde or ketone compounds of Formula (XXIII) in the presence of a suitable reducing reagent, such as sodium triacetoxyborohydride, in a suitable solvent, such as DCM, in a suitable temperature, such as 10-30 °C. (ii) Removal of the protection group under suitable conditions, such as acidic conditions for the removal of Boc.

It is to be understood that other permutations of the process steps in the process variants described above are also possible.

It will also be appreciated that, in some of the reactions mentioned hereinbefore, it may be necessary or desirable to protect any sensitive functionalities in the compounds. The instances where protection is necessary or desirable, and suitable methods for protection, are known to those skilled in the art. Conventional protecting groups may be used in accordance with standard practice (for illustration see T. W. Green, Protective Groups in Organic Synthesis, John Wiley and Sons, 1991). Thus, if reactants include groups such as amino, carboxy or hydroxy, it may be desirable to protect the group in some of the reactions mentioned herein.

A suitable protecting group for an amino or alkylamino group is, for example, an acyl group, for example an alkanoyl group such as acetyl, an alkoxycarbonyl group, for example a methoxycarbonyl, ethoxycarbonyl or t-butoxycarbonyl group, an

arylmethoxycarbonyl group, for example benzyloxycarbonyl, or an aroyl group, for example benzoyl. The deprotection conditions for the above protecting groups necessarily vary with the choice of protecting group. Thus, for example, an acyl group such as an alkanoyl or alkoxycarbonyl group or an aroyl group may be removed for example, by hydrolysis with a suitable base such as an alkali metal hydroxide, for example lithium or sodium hydroxide. Alternatively an alkoxycarbonyl group such as a t-butoxycarbonyl group may be removed, for example, by treatment with a suitable acid as hydrochloric, sulphuric, formic, phosphoric or trifluoroacetic acid, and an arylmethoxycarbonyl group such as a benzyloxycarbonyl group may be removed, for example, by hydrogenation over a catalyst such as palladium-on-carbon, or by treatment with a Lewis acid, such as boron tris(trifluoroacetate). A suitable alternative protecting group for a primary amino group is, for example, a phthaloyl group, which may be removed by treatment with an alkylamine, for example dimethylaminopropylamine, or hydrazine.

A suitable protecting group for a hydroxy group is, for example, an acyl group, for example an alkanoyl group such as acetyl, an aroyl group, for example benzoyl, an arylmethyl group, for example benzyl, or a trialkyl or diarylalkyl silane, such as TBDMS or TBDPS. The deprotection conditions for the above protecting groups will necessarily vary with the choice of protecting group. Thus, for example, an acyl group such as an alkanoyl or an aroyl group may be removed, for example, by hydrolysis with a suitable base such as an alkali metal hydroxide, for example lithium or sodium hydroxide.

Alternatively an arylmethyl group such as a benzyl group may be removed, for example, by hydrogenation over a catalyst such as palladium-on-carbon.

A suitable protecting group for a carboxy group is, for example, an esterifying group, for example a methyl or an ethyl group which may be removed, for example, by hydrolysis with a base such as sodium hydroxide, or for example a t-butyl group which may be removed, for example, by treatment with an acid, such as trifluoroacetic acid, or for example a benzyl group which may be removed, for example, by hydrogenation over a catalyst such as palladium-on-carbon.

The protecting groups may be removed at any convenient stage in the synthesis using conventional techniques well known in the chemical art.

Certain of the intermediates defined herein are novel and these are provided as further features of the specification. Biological Assays

The following assays were used to measure the effects of the compounds of the present specification.

ERq binding assay

The ability of compounds to bind to isolated Estrogen Receptor Alpha Ligand binding domain (ER alpha - LBD (GST)) was assessed in competition assays using a LanthaScreen™ Time-Resolved Fluorescence Resonance Energy Transfer (TR-FRET) detection end-point. For the LanthaScreen TR-FRET endpoint, a suitable fluorophore (Fluormone ES2, ThermoFisher, Product code P2645) and recombinant human Estrogen Receptor alpha ligand binding domain, residues 307-554 (expressed and purified in-house) were used to measure compound binding. The assay principle is that ER alpha -LBD (GST) is added to a fluorescent ligand to form a receptor/fluorophore complex. A terbium- labelled anti-GST antibody (Product code PV3551) is used to indirectly label the receptor by binding to its GST tag, and competitive binding is detected by a test compound's ability to displace the fluorescent ligand, resulting in a loss of TR-FRET signal between the Tb- anti-GST antibody and the tracer. The assay was performed as follows with all reagent additions carried out using the Beckman Coulter BioRAPTR FRD microfluidic

workstation:

1. Acoustic dispense 120 nL of the test compound into a black low volume 384 well assay plates.

2. Prepare lx ER alpha -LBD/Tb-antiGST Ab in ES2 screening buffer and

incubate for 15 minutes.

3. Dispense 6 of the lx AR-LBD/Tb-anti-GST Ab reagent into each well of the assay plate followed by 6 of Fluorophore reagent into each well of the assay plate

4. Cover the assay plate to protect the reagents from light and evaporation, and incubate at room temperature for 4 hours.

5. Excite at 337 nm and measure the fluorescent emission signal of each well at 490 nm and 520 nm using the BMG PheraSTAR.

Compounds were dosed directly from a compound source microplate containing serially diluted compound (4 wells containing 10 mM, 0.1 mM, 1 mM and 10 nM final compound respectively) to an assay microplate using the Labcyte Echo 550. The Echo 550 is a liquid handler that uses acoustic technology to perform direct microplate -to-microplate transfers of DMSO compound solutions and the system can be programmed to transfer multiple small nL volumes of compound from the different source plate wells to give the desired serial dilution of compound in the assay which is then back-filled to normalise the DMSO concentration across the dilution range.

In total 120 nL of compound plus DMSO were added to each well and compounds were tested in a 12-point concentration response format over a final compound

concentration range of 10, 2.917, 1.042, 0.2083, 0.1, 0.0292, 0.0104, 0.002083, 0.001, 0.0002917, 0.0001042, and 0.00001 μΜ respectively. TR-FRET dose response data obtained with each compound was exported into a suitable software package (such as Origin or Genedata) to perform curve fitting analysis. Competitive ER alpha binding was expressed as an IC50 value. This was determined by calculation of the concentration of compound that was required to give a 50% reduction in tracer compound binding to ER alpha-LBD.

MCF-7 ER down-regulation assay

The ability of compounds to down-regulate Estrogen Receptor (ER) numbers was assessed in a cell based immuno-fluorescence assay using the MCF-7 human ductal carcinoma breast cell line. MCF-7 cells were revived directly from a cryovial (approx 5 x 10⁶ cells) in Assay Medium (phenol red free Dulbecco's Modified Eagle's medium

(DMEM); Sigma D5921) containing 2mM L-Glutamine and 5%> (v/v) Charcoal/Dextran treated foetal calf serum. Cells were syringed once using a sterile 18G x 1.5 inch (1.2 x 40 mm) broad gauge needle and cell density was measured using a Coulter Counter

(Beckman). Cells were further diluted in Assay Medium to a density of 3.75 x 10⁴ cells per mL and 40 per well added to transparent bottomed, black, tissue culture -treated 384 well plates (Costar, No. 3712) using a Thermo Scientific Matrix WellMate or Thermo Multidrop. Following cell seeding, plates were incubated overnight at 37 °C, 5%> CO2 (Liconic carousel incubator). Test data was generated using the LabCyte Echo™ model 555 compound reformatter which is part of an automated workcell (Integrated Echo 2 workcell). Compound stock solutions (10 mM) of the test compounds were used to generate a 384 well compound dosing plate (Labcyte P-05525-CV1). 40 μΐ, of each of the 10 mM compound stock solutions was dispensed into the first quadrant well and then 1 : 100 step-wise serial dilutions in DMSO were performed using a Hydra II (MATRIX UK) liquid handling unit to give 40 μΐ, of diluted compound into quadrant wells 2 (0.1 mM), 3 (1 μΜ) and 4 (0.01 μΜ), respectively. 40 μΐ. of DMSO added to wells in row P on the source plate allowed for DMSO normalisation across the dose range. To dose the control wells 40 μΐ of DMSO was added to row 01 and 40 μΐ of 100 μΜ fulvestrant in DMSO was added to row 03 on the compound source plate.

The Echo uses acoustic technology to perform direct microplate-to-microplate transfers of DMSO compound solutions to assay plates. The system can be programmed to transfer volumes as low as 2.5 nL in multiple increments between microplates and in so doing generates a serial dilution of compound in the assay plate which is then back-filled to normalise the DMSO concentration across the dilution range. Compounds were dispensed onto the cell plates with a compound source plate prepared as above producing a 12 point duplicate 3 μΜ to 3 pM dose range with 3 -fold dilutions and one final 10-fold dilution using the Integrated Echo 2 workcell. The maximum signal control wells were dosed with DMSO to give a final concentration of 0.3%, and the minimum signal control wells were dosed with fulvestrant to give a final concentration of 100 nM accordingly. Plates were further incubated for 18-22 hours at 37 °C, 5%> C0₂ and then fixed by the addition of 20 μί of 11.1%> (v/v) formaldehyde solution (in phosphate buffered saline (PBS)) giving a final formaldehyde concentration of 3.7% (v/v). Cells were fixed at room temperature for 20 mins before being washed two times with 250 μΐ_^ PBS/Proclin (PBS with a Biocide preservative) using a BioTek platewasher, 40 μΐ_^ of PBS/Proclin was then added to all wells and the plates stored at 4 °C. The fixing method described above was carried out on the Integrated Echo 2 workcell. Immunostaining was performed using an automated AutoElisa workcell. The PBS/Proclin was aspirated from all wells and the cells permeabilised with 40 μΐ_^ PBS containing 0.5% Tween™ 20 (v/v) for 1 hour at room temperature. The plates were washed three times in 250 μΐ, of PBS/0.05%> (v/v) Tween 20 with Proclin (PBST with a Biocide preservative) and then 20 μΐ_^ of ERa (SP1) Rabbit monoclonal antibody (Thermofisher) 1 : 1000 in PBS/Tween™/3% (w/v) Bovine Serum Albumin was added. The plates were incubated overnight at 4 °C (Liconic carousel incubator) and then washed three times in 250 of PBS/0.05% (v/v) Tween™ 20 with Proclin (PBST). The plates were then incubated with 20 μΐ ννεΐΐ of a goat anti-rabbit IgG AlexaFluor 594 or goat anti-rabbit AlexaFluor 488 antibody (Molecular Probes) with Hoechst at 1 :5000 in PBS/Tween™/3% (w/v) Bovine Serum Albumin for lhour at room temperature. The plates were then washed three times in 250 μΐ, of PBS/0.05% (v/v) Tween™ 20 with Proclin (PBST with a Biocide preservative). 20 μΐ, of PBS was added to each well and the plates covered with a black plate seal and stored at 4 °C before being read. Plates were read using a Cellomics Arrayscan reading the 594 nm (24 hr time point) or 488 nm (5 hr timepoint) fluorescence to measure the ERa receptor level in each well. The mean total intensity was normalized for cell number giving the total intensity per cell. The data was exported into a suitable software package (such as Origin) to perform curve fitting analysis. Down-regulation of the ERa receptor was expressed as an IC50 value and was determined by calculation of the concentration of compound that was required to give a 50% reduction of the average maximum Total Intensity signal.

The data shown in Table A were generated (the data below may be a result from a single experiment or an average of two or more experiments):

Table A

According to a further aspect of the specification there is provided a pharmaceutical composition, which comprises a compound of the Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, as defined hereinbefore in association with a pharmaceutically acceptable excipient.

Suitable pharmaceutically acceptable excipients for a tablet formulation include, for example, inert diluents, granulating and disintegrating agents, binding agents, lubricating agents, preservative agents and antioxidants. A further suitable pharmaceutically acceptable excipient may be a chelating agent. Tablet formulations may be uncoated or coated either to modify their disintegration and the subsequent absorption of the active ingredient within the gastrointestinal tract, or to improve their stability and/or appearance, in either case, using conventional coating agents and procedures well known in the art.

Compositions for oral use may alternatively be in the form of hard gelatin capsules in which the active ingredient is mixed with an inert solid diluent, or as soft gelatin capsules in which the active ingredient is mixed with water or an oil.

Aqueous suspensions generally contain the active ingredient in finely powdered form together with one or more suspending agents, dispersing or wetting agents. The aqueous suspensions may also contain one or more preservatives, anti-oxidants, colouring agents, flavouring agents, and/or sweetening agents.

Oily suspensions may be formulated by suspending the active ingredient in a vegetable oil or in a mineral oil. The oily suspensions may also contain a thickening agent. Sweetening agents such as those set out above, and flavouring agents may be added to provide a palatable oral preparation. These compositions may be preserved by the addition of an anti-oxidant. Dispersible powders and granules suitable for preparation of an aqueous suspension by the addition of water generally contain the active ingredient together with a dispersing or wetting agent, suspending agent and one or more preservatives. Additional excipients such as sweetening, flavouring and colouring agents, may also be present.

The pharmaceutical compositions of the specification may also be in the form of oil-in-water emulsions. The oily phase may be a vegetable oil or a mineral oil or a mixture of any of these. The emulsions may also contain sweetening, flavouring and preservative agents.

Syrups and elixirs may be formulated with sweetening agents, and may also contain a demulcent, preservative, flavouring and/or colouring agent.

For further information on formulation the reader is referred to Chapter 25.2 in Volume 5 of Comprehensive Medicinal Chemistry (Corwin Hansch; Chairman of Editorial Board), Pergamon Press 1990.

The amount of active ingredient that is combined with one or more excipients to produce a single dosage form will necessarily vary depending upon the host treated and the particular route of administration. For example, oral administration to humans will generally require, for example, from 1 mg to 2 g of active agent to be administered compounded with an appropriate and convenient amount of excipients which may vary from about 3 to about 98 percent by weight of the total composition. It will be understood that, if a large dosage is required, multiple dosage forms may be required, for example two or more tablets or capsules, with the dose of active ingredient divided conveniently between them. Typically, unit dosage forms will contain about 10 mg to lg of a compound of this specification.

The size of the dose for therapeutic or prophylactic purposes of compounds of the present specification will naturally vary according to the nature and severity of the disease state, the age and sex of the animal or patient and the route of administration, according to well known principles of medicine.

In using compounds of the present specification for therapeutic or prophylactic purposes it will generally be administered so that a daily dose in the range, for example, 1 mg/kg to 100 mg/kg body weight is received, given if required in divided doses. In one aspect of the specification, compounds of the present specification or pharmaceutically acceptable salts thereof, are administered as tablets comprising lOmg to lOOOmg of the compound of the specification (or a pharmaceutically acceptable salt thereof), wherein one or more tablets are administered as required to achieve the desired dose.

As stated above, it is known that signalling through ERa causes tumourigenesis by one or more of the effects of mediating proliferation of cancer and other cells, mediating angiogenic events and mediating the motility, migration and invasiveness of cancer cells. We have found that the compounds of the present specification possess potent anti-tumour activity which it is believed is obtained by way of antagonism and down-regulation of ERa that is involved in the signal transduction steps which lead to the proliferation and survival of tumour cells and the invasiveness and migratory ability of metastasising tumour cells.

Accordingly, the compounds of the present specification may be of value as anti- tumour agents, in particular as selective inhibitors of the proliferation, survival, motility, dissemination and invasiveness of mammalian cancer cells leading to inhibition of tumour growth and survival and to inhibition of metastatic tumour growth. Particularly, the compounds of the present specification may be of value as anti-proliferative and anti- invasive agents in the containment and/or treatment of solid tumour disease. Particularly, the compounds of the present specification may be useful in the prevention or treatment of those tumours which are sensitive to inhibition of ERa and that are involved in the signal transduction steps which lead to the proliferation and survival of tumour cells and the migratory ability and invasiveness of metastasising tumour cells. Further, the compounds of the present specification may be useful in the prevention or treatment of those tumours which are mediated alone or in part by antagonism and down-regulation of ERa, i.e. the compounds may be used to produce an ERa inhibitory effect in a warm-blooded animal in need of such treatment.

According to a further aspect of the specification there is provided a compound of the Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, as defined hereinbefore for use as a medicament. According to a further aspect of the specification there is provided the use of a compound of the Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, as defined hereinbefore, as a medicament.

According to a further aspect of the specification there is provided the use of a compound of the Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, as defined hereinbefore, in the manufacture of a medicament.

According to a further aspect of the specification, there is provided a compound of the Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, as defined hereinbefore for use in the production of an anti -proliferative effect in a warm-blooded animal such as man.

According to a further aspect of the specification, there is provided the use of a compound of the Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, as defined hereinbefore, for the production of an anti-proliferative effect in a warm-blooded animal such as man.

According to a further aspect of the specification there is provided the use of a compound of the Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, as defined hereinbefore, in the manufacture of a medicament for use in the production of an anti-proliferative effect in a warm-blooded animal such as man.

According to a further aspect of the specification there is provided a method for producing an anti-proliferative effect in a warm-blooded animal, such as man, in need of such treatment which comprises administering to said animal an effective amount of a compound of the Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, as defined hereinbefore.

According to a further aspect of the specification there is provided a compound of the Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, as defined hereinbefore for use in a warm-blooded animal such as man as an anti -invasive agent in the containment and/or treatment of solid tumour disease.

According to a further aspect of the specification there is provided the use of a compound of the Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, as defined hereinbefore, as an anti-invasive agent in the containment and/or treatment of solid tumour disease. According to a further aspect of the specification there is provided the use of a compound of the Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, as defined hereinbefore, in the manufacture of a medicament for use in a warm-blooded animal such as man as an anti-invasive agent in the containment and/or treatment of solid tumour disease.

According to a further aspect of the specification there is provided a method for producing an anti-invasive effect by the containment and/or treatment of solid tumour disease in a warm-blooded animal, such as man, in need of such treatment which comprises administering to said animal an effective amount of a compound of the Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, as defined hereinbefore.

According to a further aspect of the specification, there is provided a compound of the Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, as defined hereinbefore, for use in the prevention or treatment of cancer in a warm-blooded animal such as man.

According to a further aspect of the specification there is provided the use of a compound of the Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, as defined hereinbefore in the prevention or treatment of cancer in a warm-blooded animal such as man.

According to a further aspect of the specification there is provided the use of a compound of the Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, as defined hereinbefore in the manufacture of a medicament for use in the prevention or treatment of cancer in a warm-blooded animal such as man.

According to a further aspect of the specification there is provided a method for the prevention or treatment of cancer in a warm-blooded animal, such as man, in need of such treatment which comprises administering to said animal an effective amount of a compound of the Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, as defined hereinbefore.

According to a further aspect of the specification, there is provided a compound of the Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, as defined hereinbefore for use in the prevention or treatment of solid tumour disease in a warmblooded animal such as man. According to a further aspect of the specification there is provided the use of a compound of the Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, as defined hereinbefore, in the prevention or treatment of solid tumour disease in a warmblooded animal such as man.

According to a further aspect of the specification there is provided the use of a compound of the Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, as defined hereinbefore, in the manufacture of a medicament for use in the prevention or treatment of solid tumour disease in a warm-blooded animal such as man.

According to a further aspect of the specification there is provided a method for the prevention or treatment of solid tumour disease in a warm-blooded animal, such as man, in need of such treatment which comprises administering to said animal an effective amount of a compound of the Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, as defined hereinbefore.

According to a further aspect of the specification there is provided a compound of the Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, as defined hereinbefore, for use in the prevention or treatment of those tumours which are sensitive to inhibition of ERa that are involved in the signal transduction steps which lead to the proliferation, survival, invasiveness and migratory ability of tumour cells.

According to a further aspect of the specification there is provided the use of a compound of the Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, as defined hereinbefore, in the prevention or treatment of those tumours which are sensitive to inhibition of ERa that are involved in the signal transduction steps which lead to the proliferation, survival, invasiveness and migratory ability of tumour cells.

According to a further aspect of the specification there is provided the use of a compound of the Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, as defined hereinbefore, in the manufacture of a medicament for use in the prevention or treatment of those tumours which are sensitive to inhibition of ERa that are involved in the signal transduction steps which lead to the proliferation, survival, invasiveness and migratory ability of tumour cells. According to a further aspect of the specification there is provided a method for the prevention or treatment of those tumours which are sensitive to inhibition of ERa that are involved in the signal transduction steps which lead to the proliferation, survival, invasiveness and migratory ability of tumour cells which comprises administering to said animal an effective amount of a compound of the Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, as defined hereinbefore.

According to a further aspect of the specification there is provided a compound of the Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, as defined hereinbefore for use in providing an inhibitory effect on ERa.

According to a further aspect of the specification there is provided the use of a compound of the Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, as defined hereinbefore in providing an inhibitory effect on ERa.

According to a further aspect of the specification there is provided the use of a compound of the Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, as defined hereinbefore in the manufacture of a medicament for use in providing an inhibitory effect on ERa.

According to a further aspect of the specification there is provided a method for providing an inhibitory effect on ERa which comprises administering an effective amount of a compound of the Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, as defined hereinbefore.

According to a further aspect of the specification there is provided a compound of the Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, as defined hereinbefore, for use in providing a selective inhibitory effect on ERa.

According to a further aspect of the specification there is provided the use of a compound of the Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, as defined hereinbefore, in providing a selective inhibitory effect on ERa.

According to a further aspect of the specification there is provided the use of a compound of the Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, as defined hereinbefore, in the manufacture of a medicament for use in providing a selective inhibitory effect on ERa. According to a further aspect of the specification there is also provided a method for providing a selective inhibitory effect on ERa which comprises administering an effective amount of a compound of the Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, as defined hereinbefore.

Described herein are compounds that can bind to ERa ligand binding domain and are selective estrogen receptor degraders. In biochemical and cell based assays the compounds of the present specification are shown to be potent estrogen receptor binders and reduce cellular levels of ERa and may therefore be useful in the treatment of estrogen sensitive diseases or conditions (including diseases that have developed resistance to endocrine therapies), i.e. for use in the treatment of cancer of the breast and gynaecological cancers (including endometrial, ovarian and cervical) and cancers expressing ERa mutated proteins which may be de novo mutations or have arisen as a result of treatment with a prior endocrine therapy such as an aromatase inhibitor.

According to a further aspect of the specification there is provided a compound of the Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, as defined hereinbefore, for use in the treatment of breast or gynaecological cancers.

According to a further aspect of the specification there is provided the use of a compound of the Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, as defined hereinbefore, in the treatment of breast or gynaecological cancers.

According to a further aspect of the specification there is provided the use of a compound of the Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, as defined hereinbefore, in the manufacture of a medicament for use in the treatment of breast or gynaecological cancers.

According to a further aspect of the specification there is provided a method for treating breast or gynaecological cancers, which comprises administering an effective amount of a compound of the Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, as defined hereinbefore.

According to a further aspect of the specification there is provided a compound of the Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, as defined hereinbefore, for use in the treatment of cancer of the breast, endometrium, ovary or cervix.

According to a further aspect of the specification there is provided the use of a compound of the Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, as defined hereinbefore, in the treatment of cancer of the breast, endometrium, ovary or cervix.

According to a further aspect of the specification there is provided the use of a compound of the Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, as defined hereinbefore, in the manufacture of a medicament for use in the treatment of cancer of the breast, endometrium, ovary or cervix.

According to a further aspect of the specification there is provided a method for treating cancer of the breast, endometrium, ovary or cervix, which comprises administering an effective amount of a compound of the Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, as defined hereinbefore.

According to a further aspect of the specification there is provided a compound of the Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, as defined hereinbefore, for use in the treatment of breast cancer.

According to a further aspect of the specification there is provided the use of a compound of the Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, as defined hereinbefore, in the treatment of breast cancer.

According to a further aspect of the specification there is provided the use of a compound of the Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, as defined hereinbefore, in the manufacture of a medicament for use in the treatment of breast cancer.

According to a further aspect of the specification there is provided a method for treating breast cancer, which comprises administering an effective amount of a compound of the Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, as defined hereinbefore.

According to a further aspect of the specification there is provided a compound of the Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, as defined hereinbefore, for use in the treatment of breast cancer, wherein the cancer has developed resistance to one or more other endocrine therapies.

According to a further aspect of the specification there is provided the use of a compound of the Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, as defined hereinbefore, in the treatment of breast cancer, wherein the cancer has developed resistance to one or more other endocrine therapies.

According to a further aspect of the specification there is provided the use of a compound of the Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, as defined hereinbefore, in the manufacture of a medicament for use in the treatment of breast cancer, wherein the cancer has developed resistance to one or more other endocrine therapies.

According to a further aspect of the specification there is provided a method for treating breast cancer, wherein the cancer has developed resistance to one or more other endocrine therapies, which comprises administering an effective amount of a compound of the Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, as defined hereinbefore.

In one feature of the specification, the cancer to be treated is breast cancer. In a further aspect of this feature, the breast cancer is Estrogen Receptor +ve (ER+ve).

According to a further aspect of the specification there is provided a compound of the Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, as defined hereinbefore, for use in the treatment of ER+ve breast cancer.

According to a further aspect of the specification there is provided the use of a compound of the Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, as defined herein before in the treatment of ER+ve breast cancer.

According to a further aspect of the specification there is provided the use of a compound of the Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, as defined herein before in the manufacture of a medicament for use in the treatment of ER+ve breast cancer.

According to a further aspect of the specification there is provided a method for treating ER+ve breast cancer, which comprises administering an effective amount of a compound of the Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, as defined hereinbefore.

The anti-cancer treatment defined herein may be applied as a sole therapy or may involve, in addition to the compounds of the specification, conventional surgery or radiotherapy or chemotherapy.

Accordingly, in one embodiment there is provided a compound of Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, and an additional anti-tumour substance for the conjoint treatment of cancer.

In a further embodiment there is provided the use of a compound of Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, in combination with an additional anti-tumour substance for the conjoint treatment of cancer.

In a further embodiment there is provided the use of a compound of Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, in combination with an additional anti-tumour substance for manufacture of a medicament for the conjoint treatment of cancer.

In one embodiment there is provided a method of the conjoint treatment of cancer in a warm-blooded animal, such as man, in need of such treatment which comprises administering to said animal a compound of Formula (I), (IA) or (IZ), or a

pharmaceutically acceptable salt thereof, and an additional anti-tumour substance.

In a further embodiment there is provided a combination suitable for use in the treatment of cancer comprising a compound of the Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, and another anti-tumour agent, wherein the another anti -tumour agent is the standard of care for the specific cancer to be treated; the person skilled in the art will understand the meaning of "standard of care".

In a further embodiment there is provided the use of a compound of Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, in combination with another anti -tumour agent, for the treatment of cancer, wherein the another anti -tumour agent is the standard of care for the specific cancer to be treated; the person skilled in the art will understand the meaning of "standard of care".

In a further embodiment there is provided the use of a compound of Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, in combination with an another anti -tumour agent, for manufacture of a medicament for the treatment of cancer, wherein the another anti-tumour agent is the standard of care for the specific cancer to be treated; the person skilled in the art will understand the meaning of "standard of care".

In one embodiment there is provided a method of treating cancer in a warmblooded animal, such as man, in need of such treatment which comprises administering to said animal a compound of Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, and another anti-tumour agent, wherein the another anti-tumour agent is the standard of care for the specific cancer to be treated; the person skilled in the art will understand the meaning of "standard of care".

In a further embodiment there is provided a combination suitable for use in the treatment of cancer comprising a compound of the Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, and an antihormonal agent, such as an antioestrogen (for example tamoxifen, fulverstrant, toremifene, raloxifene, droloxifene and iodoxyfene), a progestrogen (for example megestrol acetate) or an aromatase inhibitor (for example anastrozole, letrozole, vorazole and exemestane).

In a further embodiment there is provided the use of a compound of the Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, in combination with and an antihormonal agent, such as an antioestrogen (for example tamoxifen, fulverstrant, toremifene, raloxifene, droloxifene and iodoxyfene), a progestrogen (for example megestrol acetate) or an aromatase inhibitor (for example anastrozole, letrozole, vorazole and exemestane) for the treatment of cancer.

In a further embodiment there is provided the use of a compound of the Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, in combination with and an antihormonal agent, such as an antioestrogen (for example tamoxifen, fulverstrant, toremifene, raloxifene, droloxifene and iodoxyfene), a progestrogen (for example megestrol acetate) or an aromatase inhibitor (for example anastrozole, letrozole, vorazole and exemestane) in the manufacture of a medicament for the treatment of cancer.

In a further embodiment there is provided a method of treating cancer in a warmblooded animal, such as man, in need of such treatment which comprises administering to said animal a compound of Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, and an antihormonal agent, such as an antioestrogen (for example tamoxifen, fulverstrant, toremifene, raloxifene, droloxifene and iodoxyfene), a progestrogen (for example megestrol acetate) or an aromatase inhibitor (for example anastrozole, letrozole, vorazole and exemestane).

In a further aspect of the specification there is provided a combination suitable for use in the treatment of cancer comprising a compound of the Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, and an mTOR inhibitor, such as AZD2014.

In a further aspect of the specification there is provided the use of a compound of the Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, in combination with an mTOR inhibitor, such as AZD2014, for the treatment of cancer.

In a further aspect of the specification there is provided the use of a compound of the Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, in combination with an mTOR inhibitor, such as AZD2014, in the manufacture of a medicament for the treatment of cancer.

In a further aspect of the specification there is provided a method of treating cancer in a warm-blooded animal, such as man, in need of such treatment which comprises administering to said animal a compound of Formula (I), (IA) or (IZ), or a

pharmaceutically acceptable salt thereof, and an mTOR inhibitor, such as AZD2014.

In a further aspect of the specification there is provided a combination suitable for use in the treatment of cancer comprising a compound of the Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, and a CDK4/6 inhibitor, such as palbociclib.

In a further aspect of the specification there is provided the use of a compound of the Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, in combination with a CDK4/6 inhibitor, such as palbociclib, for the treatment of cancer.

In a further aspect of the specification there is provided the use of a compound of the Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, in combination with a CDK4/6 inhibitor, such as palbociclib, in the manufacture of a medicament for the treatment of cancer.

pharmaceutically acceptable salt thereof, and a CDK4/6 inhibitor, such as palbociclib. In one aspect the above combinations of a compound of the Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, with another anti-tumour agent, is suitable for use in the treatment of breast or gynaecological cancers, such as cancer of the breast, endometrium, ovary or cervix, particularly breast cancer, such as ER+ve breast cancer.

Herein, where the term "combination" is used it is to be understood that this refers to simultaneous, separate or sequential administration. In one aspect of the specification "combination" refers to simultaneous administration. In another aspect of the specification "combination" refers to separate administration. In a further aspect of the specification "combination" refers to sequential administration. Where the administration is sequential or separate, the delay in administering the second component should not be such as to lose the beneficial effect of the combination. Where a combination of two or more components is administered separately or sequential, it will be understood that the dosage regime for each component may be different to and independent of the other components.

Conveniently, the compounds of the present specification are dosed once daily.

According to a further aspect of the present specification there is provided a kit comprising a compound of Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof in combination with another anti-tumour agent selected from those described herein.

According to a further aspect of the present specification there is provided a kit comprising:

a) a compound of Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof in a first unit dosage form;

b) another anti-tumour agent selected from those described herein herein above in a second unit dosage form; and

c) container means for containing said first and second dosage forms.

According to a further aspect of the present specification there is provided a kit comprising: a) a compound of the Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof, in a first unit dosage form;

b) an anti-tumour agent selected from an anti-hormonal agent, an mTOR inhibitor, or a CDK4/6 inhibitor, in a second unit dosage form; and

c) container means for containing said first and second dosage forms.

Combination therapy as described above may be added on top of standard of care therapy typically carried out according to its usual prescribing schedule.

Although the compounds of the Formula (I), (IA) or (IZ), are primarily of value as therapeutic agents for use in warm-blooded animals (including man), they are also useful whenever it is required to inhibit ER-a. Thus, they are useful as pharmacological standards for use in the development of new biological tests and in the search for new

pharmacological agents.

Personalised Healthcare

Another aspect of the present specification is based on identifying a link between the status of the gene encoding ERa and potential susceptibility to treatment with a compound of Formula (I), (IA) or (IZ). In particular, ERa gene status may indicate that a patient is less likely to respond to exisiting hormone therapy (such as aromatase inhibitors), in part at least because some ERa mutations are though to arise as resistance mechanisms to existing treatments. A SERD, particularly a SERD which can be administered orally in potentially larger doses without excessive inconvenince, may then advantageously be used to treat patients with ERa mutations who may be resistant to other therapies. This therefore provides opportunities, methods and tools for selecting patients for treatment with a compound of Formula (I), (IA) or (IZ), particularly cancer patients. The present

specification relates to patient selection tools and methods (including personalised medicine). The selection is based on whether the tumour cells to be treated possess wild- type or mutant ERa gene. The ERa gene status could therefore be used as a biomarker to indicate that selecting treatment with a SERD may be advantageous. For the avoidance of doubt, compounds of the Formula (I), (IA) or (IZ), as described herein, are thought to be similarly active against wild-type and mutant ERa genes, at least those mutations in ERa gene identified at the date of filing this application.

There is a clear need for biomarkers that will enrich for or select patients whose tumours will respond to treatment with a SERD, such as a compound of Formula (I), (IA) or (IZ). Patient selection biomarkers that identify the patients most likely to respond to one agent over another are ideal in the treatment of cancer, since they reduce the unnecessary treatment of patients with non-responding tumours to the potential side effects of such agents.

Tumours which contain wild type ERa are believed to be susceptible to treatment with a compound of Formula (I), (IA) or (IZ), for example as a first-line treatment.

Tumours may also respond to treatment with a compound of Formula (I), (IA) or (IZ), as a second-line, third-line or subsequent therapy and this may be useful, in particular, where the tumours contain mutant ERa and may thus be resistant to existing therapies such as AIs.

For the purpose of this specification, a gene status of wild-type is meant to indicate normal or appropriate expression of the gene and normal function of the encoded protein. In contrast, mutant status is meant to indicate expression of a protein with altered function, consistent with the known roles of mutant ERa genes in cancer. Any number of genetic or epigenetic alterations, including but not limited to mutation, amplification, deletion, genomic rearrangement, or changes in methylation profile, may result in a mutant status. However, if such alterations nevertheless result in appropriate expression of the normal protein, or a functionally equivalent variant, then the gene status is regarded as wild-type. Examples of variants that typically would not result in a functional mutant gene status include synonymous coding variants and common polymorphisms (synonymous or non- synonymous). As discussed below, gene status can be assessed by a functional assay, or it may be inferred from the nature of detected deviations from a reference sequence.

In certain embodiments the wild-type or mutant status of the ERa gene is determined by the presence or absence of non-synonymous nucleic acid variations in the genes. Observed non-synonymous variations corresponding to known common

polymorphisms with no annotated functional effects do not contribute to a gene status of mutant. Other variations in the ERa gene that signify mutant status include splice site variations that decrease recognition of an intron/exon junction during processing of pre- mRNA to mRNA. This can result in exon skipping or the inclusion of normally intronic sequence in spliced mRNA (intron retention or utilization of cryptic splice junctions). This can, in turn, result in the production of aberrant protein with insertions and/or deletions relative to the normal protein. Thus, in other embodiments, the gene has a mutant status if there is a variant that alters splice site recognition sequence at an intron/exon junction.

For ESR1, reference sequences are available for the gene (GenBank accession number: NG 008493), mRNA (GenBank accession number: NM 000125), and protein (GenBank accession number: NP 000116 or Swiss-Prot accession: P03372). A person of skill in the art will be able to determine the ESR1 gene status, i.e. whether a particular ESRlgene is wild type or mutant, based on comparison of DNA or protein sequence with wild type.

It will be apparent that the gene and mRNA sequences disclosed for ERa gene are representative sequences. In normal individuals there are two copies of each gene, a maternal and paternal copy, which will likely have some sequence differences, moreover within a population there will exist numerous allelic variants of the gene sequence. Other sequences regarded as wild type include those that possess one or more synonymous changes to the nucleic acid sequence (which changes do not alter the encoded protein sequence), non-synonymous common polymorphisms (e.g. germ-line polymorphisms) which alter the protein sequence but do not affect protein function, and intronic non-splice- site sequence changes.

There are numerous techniques available to the person skilled in the art to determine the gene status of ERa. The gene status can be determined by determination of the nucleic acid sequence. This could be via direct sequencing of the full-length gene or analysis of specific sites within the gene, e.g. commonly mutated sites.

According to one aspect of the specification there is provided a method for selecting a patient for treatment with a compound of Formula (I), (IA) or (IZ), the method comprising providing a tumour cell containing sample from a patient; determining whether the ERa gene in the patient's tumour cell containing sample is wild type or mutant; and selecting a patient for treatment with a compound of Formula (I), (IA) or (IZ), based thereon.

The method may include or exclude the actual patient sample isolation step. Thus, according to one aspect of the specification there is provided a method for selecting a patient for treatment with a compound of Formula (I), (IA) or (IZ), the method comprising determining whether the ERa gene in a tumour cell containing sample previously isolated from the patient is wild type or mutant; and selecting a patient for treatment with a compound of Formula (I), (IA) or (IZ), based thereon.

In one embodiment, the patient is selected for treatment with a compound of Formula (I), (IA) or (IZ), if the tumour cell DNA has a mutant ERa gene. In other embodiments, a patient whose tumour cell DNA possesses a wild type ERa gene is selected for treatment with a compound of Formula (I), (IA) or (IZ).

In another aspect, the specification provides a method of treating a patient suffering from cancer comprising: determining the mutant or wild type status of the ERa gene in the patient's tumour cells and if the ERa gene is mutant, administering to the patient an effective amount of a compound of Formula (I), (IA) or (IZ).

According to another aspect of the specification there is provided the use of a compound of Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof to treat a cancer patient whose tumour cells have been identified as possessing a mutant ERa gene.

According to another aspect of the specification there is provided a compound of Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof for use in treating cancers with tumour cells identified as harbouring mutant ERa gene.

According to another aspect of the specification there is provided a method of treating cancers with tumour cells identified as harbouring mutant ERa gene comprising administering an effective amount of a compound of Formula (I), (IA) or (IZ), or a pharmaceutically acceptable salt thereof.

For all the aspects above, mutant forms of ERa determined/identified are at all positions across the gene. For all the aspects above, using tumours such as breast cancer as an example, particular mutant forms of ERa determined/identified are those at positions Ser463Pro, Val543Glu, Leu536Arg, Tyr537Ser, Tyr537Asn and Asp538Gly.

Examples

The specification will now be illustrated in the following Examples in which, generally:

(i) operations were carried out at ambient temperature, i.e. in the range 17 to 25 °C and under an atmosphere of an inert gas such as nitrogen unless otherwise stated;

(ii) evaporations were carried out by rotary evaporation or utilising Genevac equipment or Biotage vlO evaporator in vacuo and work-up procedures were carried out after removal of residual solids by filtration;

(iii) flash chromatography purifications were performed on an

automated Teledyne Isco CombiFlash® Rf or Teledyne Isco CombiFlash® Companion® using prepacked RediSep Rf Gold™ Silica Columns (20-40 μιη, spherical particles), GraceResolv™ Cartridges (Davisil® silica) or Silicycle cartridges (40 - 63 μιη).

(iv) preparative chromatography was performed on a Gilson prep HPLC instrument with UV collection or via supercritical fluid chromatography performed on a Waters Prep 100 SFC-MS instrument with MS- and UV- triggered collection or a Thar MultiGram III SFC instrument with UV collection;

(v) chiral preparative chromatography was performed on a Gilson instrument with UV collection (233 injector / fraction collector, 333 & 334 pumps, 155 UV detector) or a Varian Prep Star instrument (2 x SD1 pumps, 325 UV detector, 701 fraction collector) pump running with Gilson 305 injection;

(vi) yields, where present, are not necessarily the maximum attainable;

(vii) in general, the structures of end-products of the Formula I were confirmed by nuclear magnetic resonance (NMR) spectroscopy; NMR chemical shift values were measured on the delta scale [proton magnetic resonance spectra were determined using a Bruker Avance 500 (500 MHz) or Bruker Avance 400 (400 MHz) instrument];

measurements were taken at ambient temperature unless otherwise specified; the following abbreviations have been used: s, singlet; d, doublet; t, triplet; q, quartet; m, multiplet; dd, doublet of doublets; ddd, doublet of doublet of doublet; dt, doublet of triplets; bs, broad signal

(viii) in general, end-products of the Formula I were also characterised by mass spectroscopy following liquid chromatography (LCMS or UPLC); UPLC was carried out using a Waters UPLC fitted with Waters SQ mass spectrometer (Column temp 40, UV = 220-300nm, Mass Spec = ESI with positive/negative switching) at a flow rate of lml/min using a solvent system of 97% A + 3% B to 3% A to 97% B over 1.50mins (total runtime with equilibration back to starting conditions etc 1.70min), where A = 0.1% formic acid in water (for acid work) or 0.1% ammonia in water (for base work) B = acetonitrile. For acid analysis the column used was Waters Acquity HSS T3 1.8μιη 2.1 x50 mm, for base analysis the column used was Waters Acquity BEH 1.7μιη 2.1x50mm; LCMS was carried out using a Waters Alliance HT (2795) fitted with a Waters ZQ ESCi mass spectrometer and a Phenomenex Gemini -NX (50x2. lmm 5μιη) column at a flow rate of 1. lml/min 95%A to 95%B over 4 min with a 0.5 min hold. The modifier is kept at a constant 5% C (50:50 acetonitrile: water 0.1% formic acid) or D (50:50 acetonitrile: water 0.1% ammonium hydroxide (0.88 SG) depending on whether it is an acidic or basic method.

(ix) ion exchange purification was generally performed using a SCX-2 (Biotage, Propylsulfonic acid functionalized silica. Manufactured using a trifunctional silane. Non end-capped) cartridge.

(x) intermediate purity was assessed by thin layer chromatographic, mass spectral, HPLC (high performance liquid chromatography) and/or NMR analysis;

(xi) RockPhos 3^rd Generation Precatalyst was sourced from Strem Chemicals Inc. and from Sigma-Aldrich.

(xii) the following abbreviations have been used:-

AcOH acetic acid

aq. aqueous

Brettphos 3 Generation [(2-Di-cyclohexylphosphino-3,6-dimethoxy- Precatalyst 2',4',6'- triisopropyl-1 , 1 '-biphenyl)-2-(2'- amino- 1 , 1 '-biphenyl)]palladium(II) methanesulfonate

Cbz Benzyloxycarbamate

CDCI3 deutero-chloroform

Cone. concentrated

DCM dichloromethane

DIPEA diisopropylethylamine

DMF A ,N-dimethylformamide

DMSO dimethyl sulphoxide

EtOAc ethyl acetate

HPLC high performance liquid chromatography

MeCN acetonitrile

MeOH methanol

RockPhos 3rd Generation [(2-Di-tert-butylphosphino-3-methoxy-6- Precatalyst methyl-2',4',6'-triisopropyl-l , 1 '-biphenyl)-2-

(2-aminobiphenyl)]palladium(II) methanesulfonate

rt/PvT room temperature

sat. saturated

sol. Solution

TBAF Tetra-N-butylammonium fluoride

TBDMS tert-butyldimethylsilyl

TFA trifluoroacetic acid

THF tetrahydrofuran

Example 1: Preparation of N-ffS)-l-f3-fluoropropyl)pyrrolidin-3-yl)-6-ff6S.,8R)-8- methyl-7- ,2,2-trifluoroethyl)-6,7,8,9-tetrahvdro-3H-pyrazolor4,3-flisoquinolin-6- vDpyridin-3-amine

TFA (7.07 ml) was added to a solution of tert-butyl (S)-3-((6-((6S,8R)-8-methyl-7-(2,2,2- trifluoroethyl)-6,7,8,9-tetrahydro-3H-pyrazolo[4,3-i^isoquinolin-6-yl)pyridin-3

yl)amino)pyrrolidine-l-carboxylate (1.5 g, 2.83 mmol) in DCM (21.20 ml) and the resulting mixture was stirred for 2 hours at room temperature. The reaction was diluted with methanol (50 ml) and applied to prewetted (methanol) SCX-2 cartridge. The cartridge was washed with methanol (100 ml) and eluted with 1.0 M ammonia in methanol (100 mL). The eluent was concentrated in vacuo to give 6-((6S,8R)-8-methyl-7-(2,2,2- trifluoroethyl)-6,7,8,9-tetrahydro-3H-pyrazolo[4,3-f]isoquinolin-6-yl)-N-((S)-pyrrolidm^ yl)pyridin-3 -amine (1.209 g, 99 %) as a gum which was used in the next stage directly, m/z: ES+ [M+H]+ 431.

1- Fluoro-3-iodopropane (0.287 ml, 2.81 mmol) was added to a solution of 6-((65^*,8i?)-8- methyl-7-(2,2,2-trifluoroethyl)-6,7,8,9-tetrahydro-3H-pyrazolo[4,3-fJisoquinolin-6-yl)-N- ((5)-pyrrolidin-3-yl)pyridin-3 -amine (1.209 g, 2.81 mmol) and N-ethyl-N-isopropylpropan-

2- amine (0.587 ml, 3.37 mmol) in DMF (27.2 ml) and the resulting mixture stirred at room temperature for 72 hours. The reaction was partitioned between water (20 mL), and EtOAc (20 mL) and the organic separated and concentrated. Purification of the crude product was achieved by preparative HPLC (Interchim PF-30C18HP-F0220 column) using

decreasingly polar mixtures of water (containing 1% NH₃) and MeCN as eluents. Fractions containing the desired compound were evaporated to dryness. The sample was dissolved in MeOH and separated by SFC using the following chromatographic conditions: Column: Phenomonex Lux CI, 30 x 250 mm, 5 micron, Mobile phase: 30% MeOH + 0.1% NH / 70% SCCO2 to afford N-((S)-l-(3-fluoropropyl)pyrrolid^

(2,2,2-trifluoroethyl)-6,7,8,9-tetrahydro-3H-pyra^

amine (0.948 g, 68.8 %) as a yellow solid. ^!H NMR (500 MHz, CDCI3, 27 °C) 1.14 (d, 3H), 1.64 - 1.73 (m, 1H), 1.82 - 1.98 (m, 2H), 2.31 (dtd, 1H), 2.36 - 2.43 (m, 1H), 2.54 - 2.72 (m, 4H), 2.78 - 2.9 (m, 2H), 3.01 (dq, 1H), 3.17 - 3.34 (m, 2H), 3.60 (td, 1H), 3.9 - 4.07 (m, 2H), 4.46 (t, 1H), 4.55 (t, 1H), 5.03 (s, 1H), 6.85 (dd, 1H), 6.89 (d, 1H), 7.11 (d, 1H), 7.22 (d, 1H), 7.88 (d, 1H), 7.97 (d, 1H), 10.70 (s, 1H). m/z: ES+ [M+H]+ 491.

Tert-butyl (S)-3 (6 (6S,8R)-8-^

pyrazolo[4,3-fJisoquinolin-6-yl)pyridin-3-yl)amino)pyrrolidine- 1 -carboxylate used as starting material was made as follows:

Preparation of (R)-l-( lH-indazol-4-yl)propan-2-amine

ft-BuLi (46.9 mL, 75.00 mmol) was added to a solution of 4-bromo-lH-indazole (5.91 g, 30 mmol) in THF (73.1 mL) at -78 °C. After stirring for 10 minutes, the reaction was warmed to -50 °C for 30 min, then cooled back to -78 °C. (R)-ierf-butyl 4-methyl-l,2,3- oxathiazolidine-3 -carboxylate 2,2-dioxide (9.97 g, 42.0 mmol) was added in portions and the reaction was stirred for 1 hour before being allowed to warm to 0 °C. Water (100 mL) and diethyl ether (100 mL) were added and the mixture was stirred for 5 minutes. The layers were separated and the aqueous was extracted with EtOAc. The combined organics were extracted with water, then to the combined aqueous was added to 2N HC1 (100 mL). The solution was extracted with DCM (x 2) and the combined organics were dried over MgSC"4, filtered and concentrated to afford

(l-(lH-indazol-4-yl)propan-2- yl)carbamate (6.45 g, 78%) as an off-white solid. ^lH NMR (400 MHz, CDCI3, 27 °C) 1.11 (3H, d), 1.43 (9H, s), 2.95 (1H, dd), 3.24 (1H, d), 3.98 - 4.25 (1H, m), 4.51 - 4.61 (1H, m), 6.95 (1H, d), 7.30 (1H, dd), 7.39 (1H, d), 8.23 (1H, s). m/z (ES+), [M+H]+ = 276. Preparation of fR)-l-flH-indazol-4-yl)propan-2-amine

Hydrogen chloride 4M in dioxane (21.25 mL, 84.98 mmol) was added to tert-butyl (i?)-(l- (lH-indazol-4-yl)propan-2-yl)carbamate (2.34 g, 8.50 mmol) and the resulting suspension stirred overnight. The reaction was concentrated and taken up in methanol. The solution was applied to a pre-wetted (methanol) SCX-2 cartridge. The cartridge was washed with methanol and eluted with 1M ammonia in methanol solution. The eluent was concentrated to give (i?)-l-(lH-indazol-4-yl)propan-2-amine (1.20 g, 81%) as a golden gum. ^!H NMR

(400 MHz, CDCls, 27 °C) 1.20 (3H, d), 1.79 (2H, s), 2.87 (1H, dd), 3.06 (1H, dd), 3.34 - 3.45 (1H, m), 6.91 - 7.04 (1H, m), 7.28 - 7.42 (2H, m), 8.12 (1H, d). m/z: ES+ [M+H]+

176.

Preparation of fR)-l-flH-indazol-4-yl)- V-f2,2,2-trifluoroethyl)propan-2-amine

Trifluoromethanesulfomc anhydride (1.39 mL, 8.27 mmol) was added to a cooled solution of 2,2,2-trifiuoroethan-l-ol (0.57 mL, 7.88 mmol) in DCM (16.6 mL) followed by 2,6- dimethylpyridine (1.10 mL, 9.46 mmol). The reaction was allowed to warm to room temperature and stirred for 1 hour. The reaction was washed with 2N HC1 (20 mL). The organic phase was dried over MgS0₄ and filtered to give a solution of 2,2,2-trifluoroethyl trifluoromethanesulfonate which was used directly. To this solution was added to a solution of (i?)-l-(lH-indazol-4-yl)propan-2-amine (1.20 g, 6.85 mmol) and N-ethyl-N- isopropylpropan-2-amine (1.67 mL, 9.59 mmol) in 1,4-dioxane (5 mL). The reaction was stirred at 50 °C overnight. After cooling, the reaction was diluted with DCM and washed with water. The aqueous was extracted with DCM, then the combined organics were dried (Na₂S0₄) and concentrated. The crude product was purified by flash silica

chromatography, elution gradient 0-50% ethyl acetate in heptane. Pure fractions were evaporated to dryness to afford (R)-l -(lH-indazol-4-yl)-N-(2,2,2-trifluoroethyl)propan-2- amine (0.890 g, 50%) as a colourless oil. ^!H NMR (500 MHz, CDCls, 27 °C) 1.12 (3H, d), 2.96 (1H, dd), 3.08 (1H, dd), 3.13 - 3.30 (3H, m), 6.98 (1H, dd), 7.33 (1H, dd), 7.39 (1H, d), 8.12 (1H, d), 10.26 (1H, s). ¹⁹F NMR (471 MHz, CDCI3, 27 °C) -71.85 (J = 9.4). m/z: ES+ [M+H]+ 258.

Preparation of (6S,8R)-6-(5-bromopyridin-2-yl)-8-methyl-7-q,2,2-trifluoroethyl)- 6,7,8,9-tetrahvdro-3H-pyrazolo 14,3-f I isoq u inoline

Trifluoroacetic acid (4.89 mL) was added to a solution of (R)-l-(lH-indazol-4-yl)-N- (2,2,2-trifluoroethyl)propan-2-amine (5.28 g, 20.5 mmol) and 5-bromopicolinaldehyde (4.20 g, 22.6 mmol) in toluene (98 mL) under nitrogen and the resulting mixture was heated to 90 °C and stirred at 90 °C for 4 hours. The reaction mixture was diluted with EtOAc (100 mL) and washed with saturated aqueous NaHC0₃ (50 mL), saturated aqueous sodium chloride (50 mL), dried (MgS0₄), filtered and concentrated under reduced pressure to give the crude product as a brown gum. The crude product was purified by flash silica chromatography, elution gradient 0 to 50% EtOAc in heptane. Fractions were evaporated to dryness to afford (65^,,8i?)-6-(5-bromopyridin-2-yl)-8-methyl-7-(2,2,2-trifluoroethyl)- 6,7,8,9-tetrahydro-3H-pyrazolo[4,3-f]isoquinoline (7.69 g, 88%) as a beige solid. 12.5 : 1 cis to trans ratio. ^!H NMR (500 MHz, CDC1₃, 27 °C) 1.16 (3H, d), 2.90 (1H, dd), 2.93 - 3.03 (1H, m), 3.23 - 3.36 (2H, m), 3.51 - 3.59 (1H, m), 5.10 (1H, s), 6.94 (1H, d), 7.22 - 7.25 (1H, m), 7.39 (1H, d), 7.75 (1H, d), 8.06 (1H, d), 8.56 (1H, dd), 10.1 1 (1H, s). m/z: ES+ [M+H]+ 425. Preparation of fe -butyl (S)-3- 6- 6S,8R)-8-methyl-7-q,2,2-trifluoroethyl)-6 ,7,8,9- tetrahvdro-3H-pyrazolo[4 -f1iso uinolin-6-yl)pyridin-3-yl)amino)pyrrolidine-l- carboxylate

Sodium tert-butoxide (2.03 g, 21.16 mmol) and BrettPhos G3 (0.160 g, 0.18 mmol) were added to a degassed solution of tert-butyl (S)-3-aminopyrrolidine-l-carboxylate (0.739 ml, 4.23 mmol) and (65^*,8i?)-6-(5-bromopyridin-2-yl)-8-methyl-7-(2,2,2-trifiuoroethyl)-6,7,8,9- tetrahydro-3H-pyrazolo[4,3-f]isoquinoline (1.5 g, 3.53 mmol) in 1,4-dioxane (16.90 ml). The reaction was heated to 80 °C for 1 hour. After cooling, the reaction was diluted with EtOAc (20mL) and water (20mL), and the layers were separated. The aqueous was extracted with EtOAc (2x20mL), then the combined organics were washed with brine (20mL), dried over Na₂S04, filtered and concentrated. Purification was by silica gel column chromatography eluting with 0-100% ethyl acetate in heptane to give tert-butyl (5)-3-((6-((6^,8i?)-8-methyl-7-(2,2,2-trifluoroethyl)-6,7,8,9-tetrahydro-3H-pyrazolo[4,3- fJisoquinolin-6-yl)pyridin-3-yl)amino)pyrrolidine-l-carboxylate (1.511 g, 81 %) as a yellow oil. ¾ NMR (500 MHz, CDCb, 27 °C) 1.15 (d, 3H), 1.46 (s, 9H), 2.13 - 2.24 (m, 1H), 2.86 (dd, 1H), 2.97 - 3.08 (m, 1H), 3.19 - 3.35 (m, 3H), 3.43 - 3.54 (m, 3H), 3.58 - 3.64 (m, 1H), 3.67 (s, 1H), 3.75 (d, 1H), 4.00 (s, 1H), 5.04 (s, 1H), 6.87 (dd, 1H), 6.91 (d, 1H), 7.17 (d, 1H), 7.23 (d, 1H), 7.91 (d, 1H), 8.01 (s, 1H), 10.32 (s, 1H). m/z: ES+

[M+H]+ 531. Examples 2-3 (Table A below) were similarly prepared using methods analogous to those described in Example 1 . Further intermediates used in the preparation of Examples 2-3 are described as follows;

Intermediate used in the preparation of Examples 2 and 3 Intermediates for Example 2

Preparation of 2,2-difluoroethyl trifluoromethanesulfonate

Trifluoromethanesulfonic anhydride (3.97 ml, 23.5 mmol) was added dropwise to a solution of 2,2-difluoroethan-l-ol (1.75 g, 21.3 mmol) in DCM (40 mL at ) at -10 °C (salt/ice bath). Lutidine (2.98 ml, 25.6 mmol) was then added, and the reaction was stirred for 1 hour at -10 °C. The reaction was then quenched with water, and the layers were separated. The organic layer was washed with water and then dried over sodium sulfate, filtered and concentrated under reduced pressure to afford 2,2-difluoroethyl

trifluoromethanesulfonate (3.10 g, 67.9%) as a colorless liquid. ^!Η NMR (500 MHz, CDCls, 27 °C) 4.57 (2H, td), 6.03 (1H, tt).

Preparation of (R)-3-( -(|2,2-difluoroethyl)amino)propyl)-2-methylaniline

2,2-Difluoroethyl trifluoromethanesulfonate (0.789 g, 3.68 mmol) was added to a stirred solution of (i?)-3-(2-aminopropyl)-2-methylaniline (0.55 g, 3.4 mmol) and DIPEA (0.760 ml, 4.35 mmol) in 1,4-dioxane (10 mL). The reaction was heated at 65 °C for 3 hours and then cooled to room temperature. The reaction was concentrated under reduced pressure, and the resulting residue was dissolved in EtOAc (30 mL) and washed with saturated aqueous sodium hydrogen carbonate. The layers were separated, and the aqueous layer was extracted with EtOAc (20 mL). The combined organic layers were dried over sodium sulfate, filtered and concentrated under reduced pressure to give a red liquid. This oil was purified by flash silica chromatography, elution gradient 30 to 90% ethyl acetate in hexanes to give (i?)-3-(2-((2,2-difluoroethyl)amino)propyl)-2-methylaniline (0.52 g, 68%) as a gum. ^!H NMR (400 MHz, CDCb, 27 °C) 1.06 (3H, d), 2.09 (3H, s), 2.60 (1H, dd), 2.77 (1H, dd), 2.81 - 2.99 (3H, m), 3.56 (2H, br s) 5.78 (1H, tt), 6.58 (2H, d), 6.94 (1H, t). m/z: ES+ [M+H]+ 229.

Preparation of flS,3R)-l-f5-bromopyridin-2-yl)-2-f2,2-difluoroethyl)-3.,5-(iimethyl- l,2,3i4-tetrahydroisoquinolin-6-amine

5-Bromopicolinaldehyde (2.74 g, 14.72 mmol) was added to a solution of (i?)-3-(2-((2,2- difluoroethyl)amino)propyl)-2-methylaniline (1.6 g, 7.01 mmol) in acetic acid (34.4 mL) and water (0.631 mL, 35.04 mmol), and the reaction was heated at 80 °C for 3 hours. Solvent was removed under vaccum, and the resulting residue was dissolved in methanol. Sodium acetate (1.15 g, 14.0 mmol) and hydroxylamine hydrochloride (0.73 g, 11 mmol) were added, and the reaction was stirred at room temperature for 3 hours. Methanol was removed under vaccum, and the resulting residue was taken up in water. Saturated aqueous NaHC0₃ was added, and the mixture was extracted with ethyl acetate. The organic layer was dried over Na₂S04, filtered, and concentrated under reduced pressure. The resulting residue was purified by flash silica chromatography, elution gradient 0 to 95%) EtOAc in hexanes. Product fractions were concentrated under reduced pressure to afford (l^,3i?)-l-(5-bromopyridin-2-yl)-2-(2,2-difluoroethyl)-3,5-dimethyl-l,2,3,4- tetrahydroisoquinolin-6-amine (1.35 g, 49%>) as a colourless gum. ^!H NMR (DMSO- i, 27 °C) 1.01 (3H, d), 1.94 (3H, s), 2.39 - 2.64 (2H, m, obscured), 2.74 (1H, dd), 2.91 - 3.14 (1H, m), 3.23 - 3.33 (1H, m, obscured), 4.66 (2H, s), 4.81 (1H, s), 5.93 (1H, tt), 6.40 (2H, s), 7.23 (1H, d), 7.92 (1H, dd), 8.57 (1H, d). m/z: ES+ [M+H]+ 396.

Preparation of f6S,8R)-6-f5-bromopyridin-2-yl)-7-f2,2-difluoroethyl)-8-methyl- 6,7,8,9-tetrahvdro-3H-pyrazolo[4,3- 1isoguinoline

A solution of sodium nitrite (87 mg, 1.3 mmol) in water (0.43 mL) was added dropwise to a cooled solution of (15',Ji?)-l-(5-bromopyridin-2-yl)-2-(2,2-difiuoroethyl)-3,5-dimethyl- l,2,3,4-tetrahydroisoquinolin-6-amine (500 mg, 1.26 mmol) in propionic acid (4.3 mL) at - 10 °C (ice/salt bath) with vigorous stirring. After 20 minutes, the reaction was diluted with cold (0 °C) ethyl acetate (10 mL) and quenched with slow addition of ice-cold saturated aqueous NaHC0₃ (10 mL) over 15 minutes while maintaining a reaction temperature of 0 °C. The reaction mixture was then allowed to warm to room temperature over 2 hours with stirring. The layers were separated, and the aqueous layer was extracted with ethyl acetate. The combined organic layers were dried over Na₂S04, filtered, and concentrated under reduced pressure. The resulting residue was purified by flash silica chromatography, elution gradient 0 to 60% EtOAc in hexanes. Product fractions were concentrated under reduced pressure to afford (65',8i?)-6-(5-bromopyridin-2-yl)-7-(2,2-difluoroethyl)-8- methyl-6,7,8,9-tetrahydro-3H-pyrazolo[4,3_: ]isoquinoline (253 mg, 49%>) as a brown foam.

¾ NMR (DMSO-Λ, 27 °C) 1.08 (3H, d), 2.54 - 2.77 (1H, m), 2.89 (1H, dd), 3.04 - 3.24 (2H, m), 3.36 - 3.53 (1H, m), 5.05 (1H, s), 6.00 (1H, tt), 6.83 (1H, d), 7.25 (1H, d), 7.35 (1H, d), 7.97 (1H, dd), 8.08 (1H, s), 8.59 (1H, d), 12.99 (1H, s). m/z: ES+ [M+H]+ 407

Intermediates for Example 3 Starting from 4-bromo-3-fluoro-lH-indazole [obtained as follows: Selectfluor (33.6 g, 94.91 mmol) was added to a solution of 4-bromo-lH-indazole (17 g, 86.28 mmol) in DMF (173 ml) and the reaction was heated to 70 °C overnight. After cooling, the reaction mixture was poured onto water. The solid was filtered and dried, then the crude product was purified by flash silica chromatography, elution gradient 0 to 30% EtOAc in heptane. Pure fractions were evaporated to dryness to afford 4-bromo-3-f uoro-lH-indazole (3.90 g, 21 %) as a pale yellow solid. ^!H NMR (500 MHz, CDCb, 27°C) 7.24 - 7.28 (1H, m), 7.32 - 7.36 (2H, m), 9.20 (1H, s)], a sequence similar to Example 1 was carried out, except that the intermediate (6S,8R)-6-(5-bromopyridin-2-yl)- 1 -fluoro-8-methyl-7-(2,2,2- trifluoroethyl)-6,7,8,9-tetrahydro-3H-pyrazolo[4,3-f]isoquinoline was protected with a THP protecting group as tert-butyl (3S)-3-((6-((6S,8R)-l-fluoro-8-methyl-3-(tetrahydro- 2H-pyran-2-yl)-7-(2,2,2 rif uoroethyl)-6,7,8,9-tetrahydro-3H-pyrazolo[4,3-f]isoquinolin- 6-yl)pyridin-3-yl)amino)pyrrolidine-l-carboxylate, before carrying out the palladium catalyzed coupling step with tert-butyl (S)-3-aminopyrrolidine-l-carboxylate to give tert- butyl (3S)-3-((6-((6S,8R)- 1 -f uoro-8-methyl-3-(tetrahydro-2H-pyran-2-yl)-7-(2,2,2- trif uoroethyl)-6,7,8,9-tetrahydro-3H-pyrazolo[4,3-f isoquinolin-6-yl)pyridin-3- yl)amino)pyrrolidine-l-carboxylate. Deprotection of THP occurred during the Boc deprotection step with TFA to give 6-((6S,8R)-l-fluoro-8-methyl-7-(2,2,2-trifluoroethyl)- 6,7,8,9-tetrahydro-3H-pyrazolo[4,3-f]isoquinolin-6-yl)-N-((S)-pyrrolidin-3-yl)pyridin-3- amine.

Table A

LCMS

Example Structure Name 1H NMR

[M+Hl

The above description of illustrative embodiments is intended only to acquaint others skilled in the art with the Applicant's specification, its principles, and its practical application so that others skilled in the art may readily adapt and apply the specification in its numerous forms, as they may be best suited to the requirements of a particular use. This description and its specific examples, while indicating embodiments of this specification, are intended for purposes of illustration only. This specification, therefore, is not limited to the illustrative embodiments described in this specification, and may be variously modified. In addition, it is to be appreciated that various features of the specification that are, for clarity reasons, described in the context of separate embodiments, also may be combined to form a single embodiment. Conversely, various features of the specification that are, for brevity reasons, described in the context of a single embodiment, also may be combined to form sub -combinations thereof.

Claims

1. A compound of Formula (I) :

(I) wherein:

A is CR⁴ or N;

R¹ is H, F or OMe;

R² is H, F or CH₂OH;

R³ is H or F; and

R⁴ is H or F;

or a pharmaceutically acceptable salt thereof.

2. A compound of Formula (IA) :

(IA)

wherein:

A is CR⁴ or N;

R¹ is H, F or OMe;

R² is H, F or CH₂OH;

R³ is H or F; and

R⁴ is H or F;

or a pharmaceutically acceptable salt thereof

3. A compound of Formula (I) or (IA), or a pharmaceutically acceptable salt thereof, as claimed in claim 1 or claim 2, for use as a medicament.

4. A compound of Formula (I) or (IA), or a pharmaceutically acceptable salt thereof, as claimed in claim 1 or claim 2, for use in the prevention or treatment of cancer in a warm-blooded animal.

5. A method for the prevention or treatment of cancer in a warm-blooded animal, such as man, in need of such treatment which comprises administering to said animal an effective amount of a compound of the Formula (I) or (IA), or a pharmaceutically acceptable salt thereof, as claimed in claim 1 or claim 2.

6. A pharmaceutical composition comprising a compound of Formula (I) or (IA), or a pharmaceutically acceptable salt thereof, as claimed in claim 1 or claim 2, and a pharmaceutically acceptable excipient.

7. A compound of Formula (I) or (IA), or a pharmaceutically acceptable salt thereof, as claimed in claim 1 or claim 2, and an additional anti-tumour substance, for the conjoint treatment of cancer.