WO2020053660A1

WO2020053660A1 - Solid forms of a bet inhibitor

Info

Publication number: WO2020053660A1
Application number: PCT/IB2019/001015
Authority: WO
Inventors: Bo MEI; Yanlan YANG; Henrik C. Hansen
Original assignee: Zenith Epigenetics Ltd.
Priority date: 2018-09-13
Filing date: 2019-09-13
Publication date: 2020-03-19
Also published as: TW202035401A

Abstract

The present disclosure relates to a mesylate salt/co-crystal of a BET bromodomain inhibitor, l-benzyl-6-(3,5-dimethylisoxazol-4-yl)-N-methyl-lH-imidazo[4,5-b]pyridine-2-amine, that modulates or inhibits the activity of BET bromodomain-containing proteins, pharmaceutical compositions, therapeutic uses, and processes for making a mesylate salt/co-crystal of said BET bromodomain inhibitor. These inhibitors have the potential to cure, treat, or improve the lives of subjects suffering from diseases such as cancer, inflammatory and cardiovascular diseases.

Description

SOLID FORMS OF A BET INHIBITOR

[001] The invention relates to a mesylate salt/co-crystal of benzyl-6-(3,5- dimethylisoxazol-4-yl)-N-methyl-lH-imidazo[4,5-b]pyridine-2-amine that modulates or inhibits the activity of BET bromodomain-containing proteins, pharmaceutical compositions, therapeutic uses, and processes for making a mesylate salt/co-crystal of benzyl-6-(3,5- dimethylisoxazol-4-yl)-N-methyl-lH-imidazo[4,5-b]pyridine-2-amine.

BACKGROUND

[002] Therapeutic agents that modulate or inhibit the activity of BET

bromodomain-containing proteins such as BRD2, BRD3, BRD4, and BRDT have the potential to cure, treat, or improve the lives of subjects suffering from diseases such as cancer, inflammatory, and cardiovascular diseases. In particular, BET bromodomain modulators or inhibitors have the potential to treat B-acute lymphocytic leukemia, Burkitt's lymphoma, diffuse large cell lymphoma, multiple myeloma, primary plasma cell leukemia, lung cancer, bladder cancer, breast cancer, cervical cancer, colon cancer, gastric cancer, glioblastoma, prostate cancer, ovarian cancer, and neuroblastoma among others. Compounds for the treatment of such diseases and conditions are disclosed in International Patent Publication WO 2015/002754, the disclosure of which is incorporated herein by reference in its entirety.

[003] There is a large unmet need for highly pure compounds, including derivatives of benzimidazole, that exhibit good physical and/or chemical stability, solubility, and are effective for the treatment of diseases modulated by BET bromodomain-containing proteins.

[004] The free base of benzyl-6-(3,5-dimethylisoxazol-4-yl)-N-methyl-lH- imidazo[4,5-b]pyridine-2-amine is described in International patent publication WO

2015/002754 as an amorphous solid or mixture of crystalline forms. The large-scale manufacturing of a pharmaceutical composition poses many challenges to the chemist and chemical engineer. While many of these challenges relate to the handling of large quantities of reagents and control of large-scale reactions, the handling of the final product poses special challenges linked to the nature of the final active product itself. Not only should the product be prepared in high yield, be stable, and be capable of ready isolation, the product should possess properties that are suitable for the types of pharmaceutical preparations in which they are likely to be ultimately used. The stability of the active ingredient of the pharmaceutical preparation must be considered during each step of the manufacturing process, including the synthesis, isolation, bulk storage, pharmaceutical formulation and long-term storage. Each of these steps may be impacted by various environmental conditions of temperature and humidity.

[005] The pharmaceutically active substance used to prepare the pharmaceutical compositions should be as pure as possible and its stability on long-term storage should be guaranteed under a wide variety of environmental conditions. These properties are useful to prevent the appearance of unintended degradation products in pharmaceutical compositions, which degradation products may be potentially toxic or result simply in reducing the potency of the composition.

[006] A primary concern for the large-scale manufacture of pharmaceutical compounds is that the active substance should have a stable crystalline morphology to ensure consistent processing parameters and pharmaceutical quality. If an unstable crystalline form is used, crystal morphology may change during manufacture and/or storage resulting in quality control problems and formulation irregularities. Such a change may affect the reproducibility of the manufacturing process and thus lead to final formulations which do not meet the high quality and stringent requirements imposed on formulations of pharmaceutical compositions. In this regard, it should be generally borne in mind that any change to the solid state of a pharmaceutical composition which can improve its physical and chemical stability gives a significant advantage over less stable forms of the same drug.

[007] When a compound crystallizes from a solution or slurry, it may crystallize with different spatial lattice arrangements, a property referred to as "polymorphism." Each of the crystal forms is a "polymorph." While polymorphs of a given substance have the same chemical composition, they may differ from each other with respect to one or more physical properties, such as solubility, dissociation, true density, dissolution, melting point, crystal shape, compaction behavior, flow properties, and/or solid state stability.

[008] As described generally above, the polymorphic behavior of drugs can be of great importance in pharmacy and pharmacology. The differences in physical properties exhibited by polymorphs affect practical parameters such as storage stability,

compressibility and density (important in formulation and product manufacturing), and dissolution rates (an important factor in determining bio-availability). Differences in stability can result from changes in chemical reactivity (e.g., differential oxidation, such that a dosage form discolors more rapidly when it is one polymorph than when it is another polymorph) or mechanical changes (e.g., tablets crumble on storage as a kinetically favored polymorph converts to a thermodynamically more stable polymorph) or both (e.g., tablets of one polymorph are more susceptible to breakdown at high humidity). In addition, the physical properties of the crystal may be important in processing: for example, one polymorph might be more likely to form solvates that cause the solid form to aggregate and increase the difficulty of solid handling, or might be difficult to filter and wash free of impurities (i.e., particle shape and size distribution might be different between one polymorph relative to other).

[009] While drug formulations having improved chemical and physical properties are desired, there is no predictable means for preparing new drug forms (e.g., polymorphs) of existing molecules for such formulations. These new forms would provide consistency in physical properties over a range of environments common to manufacturing and composition usage. Thus, there is a need for new drug forms that are useful for inhibiting BET activity in vitro and in vivo, and are useful for the treatment of disorders mediated by BET proteins, particularly cancer, and other disorders associated with BET activity, as well as having properties suitable for large-scale manufacturing and formulation.

SUMMARY

[0010] l-Benzyl-6-(3,5-dimethylisoxazol-4-yl)-N-methyl-lFI-imidazo[4,5-b]pyridine- 2-amine (Compound I):

Compound I

is known to modulate BET bromodomain-containing proteins. The synthesis and utility of Compound I is described in International patent publication WO 2015/002754, which is incorporated herein by reference.

[0011] The invention is based, in part, on the discovery that a particular polymorphic form of Compound I (i.e., the mesylate salt/co-crystal of Compound I) is surprisingly stable and possess superior solubility profiles over the mixture of polymophs in International patent publication WO 2015/002754. Thus, the invention provides a mesylate salt/co-crystal of Compound I in crystalline Form I. The invention also provides hydrates, and solvates of the mesylate salt/co-crystal of Compound I Form I; methods for making the mesylate salt/co-crystal of Compound I Form I, or a pharmaceutically acceptable hydrate or solvate thereof; pharmaceutical compositions comprising a mesylate salt/co-crystal of Compound I Form I, or a pharmaceutically acceptable hydrate or solvate thereof; and methods for using a mesylate salt/co-crystal of Compound I Form I, or a hydrate or solvate thereof, in the treatment of diseases mediated by BET bromodomain-containing proteins.

[0012] One embodiment is directed to a mesylate salt/co-crystal of Compound I in crystalline Form I, characterized by an X-ray powder diffractogram (XRPD) comprising peak, in terms of 2-theta, at about 16.9 ± 2.0 degrees, as determined on a diffractometer using Cu- K_a radiation tube.

[0013] One embodiment is directed to a mesylate salt/co-crystal of Compound I, characterized by an X-ray powder diffractogram (XRPD) comprising two or more of the following peaks, in terms of 2-theta, at 8.4 ± 0.2, 10.6 ± 0.2, 11.7 ± 0.2, 14.5 ± 0.2, 15.3 ± 0.2, 16.9 ± 0.2, 18.2 ± 0.2, 19.0 ± 0.2, 19.9 ± 0.2, 20.5 ± 0.2, 22.6 ± 0.2, 23.8 ± 0.2, 24.5 ± 0.2, and 27.6 ± 0.2 degrees, as determined on a diffractometer using Cu-K_a radiation tube.

[0014] One embodiment is directed to a mesylate salt/co-crystal of Compound I Form I, characterized by an X-ray powder diffractogram (XRPD) pattern substantially as shown in Figure 1, as determined on a diffractometer using Cu-K_a radiation tube.

[0015] The mesylate salt/co-crystal of Compound I is substantially in crystalline Form I. In some embodiments, at least 85% by weight of the mesylate of Compound I is in crystalline Form I. In some embodiments, at least 95% by weight is in crystalline Form I.

[0016] One embodiment is directed to a pharmaceutical composition comprising a mesylate salt/co-crystal of Compound I Form I, and one or more pharmaceutically acceptable carriers.

[0017] One embodiment is directed to a method of treating a disease, at least in part, mediated by BET bromodomain-containing proteins in a subject in need thereof, comprising administrating a therapeutically effective amount of a mesylate salt/co-crystal of Compound I in crystalline Form I. In one embodiment, the subject is human and the disease is selected from cancers, inflammatory diseases, and cardiovascular diseases. In one embodiment, the subject is human and the disease is a cancer selected from B-acute lymphocytic leukemia, Burkitt's lymphoma, diffuse large cell lymphoma, multiple myeloma, primary plasma cell leukemia, lung cancer, bladder cancer, cervical cancer, colon cancer, gastric cancer, glioblastoma, ovarian cancer, and neuroblastoma. In one embodiment, the disease is prostate cancer. In one embodiment, the disease is castration-resistant prostate cancer. In one embodiment, the disease is breast cancer. In one embodiment, the disease is triple-negative breast cancer. In one embodiment, the disease is estrogen-receptor positive breast cancer. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 shows an X-ray powder diffractogram (XRPD) of a mesylate salt/co crystal of Compound I Form I.

[0019] Figure 2 shows a differential scanning calorimeter (DSC) curve of a mesylate salt/co-crystal of Compound I Form I.

[0020] Figure 3 shows a thermogravimetric analysis (TGA) of a mesylate salt/co crystal of Compound I Form I.

[0021] Figure 4 shows an XRPD of a phosphate salt/co-crystal of Compound I

Form A.

[0022] Figure 5 shows a DSC curve of a phosphate salt/co-crystal of Compound I

Form A.

[0023] Figure 6 shows a TGA of a phosphate salt/co-crystal of Compound I Form A.

DETAILED DESCRIPTION

[0024] The free base form of Compound I, as disclosed in WO 2015/002754, is produced as an amorphous solid or a mixture of crystalline forms. The free base was identified to exist in at least seven polymorphic forms. Each of these forms exhibited limited stability and solubility under tested conditions, indicating that none were suitable for large- scale manufacturing and product storage. Many salts of Compound I were also evaluated, leading to the identification of additional polymorphs for these salts. Most of these crystalline salts/co-crystals were also unstable under one or more tested conditions or exhibited unacceptable solubility profiles - or both.

[0025] Surprisingly, the mesylate salt/co-crystal of Compound I Form I is both stable and soluble, making it suitable for both large-scale manufacturing and product storage. Definitions

[0026] As used in the present specification, the following words, phrases and symbols are generally intended to have the meanings as set forth below, except to the extent that the context in which they are used indicates otherwise. The following terms have the indicated meanings throughout.

[0027] The term "crystalline" as used herein refers to a solid form in which the material has a regular ordered internal structure at the molecular level and gives a distinctive XRPD pattern with defined peaks. Such materials when heated sufficiently will also exhibit the properties of a liquid, but the form change from solid to liquid is characterized by a phase change at the melting point. [0028] The term "substantially" when qualifying Compound I Form I described herein is intended to mean that greater than 50%; or greater than 60%; or greater than 70%; or greater than 80%; or greater than 85%; or greater than 90%; or greater than 95%; or greater than 99% of the compound is present in the designated form.

[0029] The term "salt/co-crystal" refers to a formation resulting from the interaction between Compound I and another component (e.g. a pharmaceutically acceptable acid such as methanesulfonic acid).

[0030] "Subject" refers to an animal, such as a mammal, that has been or will be the object of treatment, observation, or experiment. The methods described herein may be useful for both human therapy and veterinary applications. In one embodiment, the subject is a human.

[0031] As used herein, "diseases mediated by BET bromodomain-containing proteins" refers to diseases that are capable of being treated by a compound, such as Compound I, that inhibits or modulates the activity of a BET bromodomain-containing protein in vivo.

[0032] As used herein, "treatment" or "treating" refers to an amelioration of a disease or disorder, or at least one discernible symptom thereof. In another embodiment, "treatment" or "treating" refers to an amelioration of at least one measurable physical parameter, not necessarily discernible by the subject. In yet another embodiment,

"treatment" or "treating" refers to inhibiting the progression of a disease or disorder, either physically, e.g., stabilization of a discernible symptom, physiologically, e.g., stabilization of a physical parameter, or both. In yet another embodiment, "treatment" or "treating" refers to delaying the onset of a disease or disorder. For example, treating a cholesterol disorder may comprise decreasing blood cholesterol levels.

[0033] As used herein, "cardiovascular disease" refers to diseases, disorders and conditions of the heart and circulatory system that are mediated by BET inhibition.

Exemplary cardiovascular diseases, including cholesterol- or lipid-related disorders, include, but are not limited to, acute coronary syndrome, angina, arteriosclerosis, atherosclerosis, carotid atherosclerosis, cerebrovascular disease, cerebral infarction, congestive heart failure, congenital heart disease, coronary heart disease, coronary artery disease, coronary plaque stabilization, dyslipidemias, dyslipoproteinemias, endothelium dysfunctions, familial hypercholesterolemia, familial combined hyperlipidemia, hypoalphalipoproteinemia, hypertriglyceridemia, hyperbetalipoproteinemia, hypercholesterolemia, hypertension, hyperlipidemia, intermittent claudication, ischemia, ischemia reperfusion injury, ischemic heart diseases, cardiac ischemia, metabolic syndrome, multi-infarct dementia, myocardial infarction, obesity, peripheral vascular disease, reperfusion injury, restenosis, renal artery atherosclerosis, rheumatic heart disease, stroke, thrombotic disorder, transitory ischemic attacks, and lipoprotein abnormalities associated with Alzheimer's disease, obesity, diabetes mellitus, syndrome X, impotence, multiple sclerosis, and Parkinson's disease.

[0034] As used herein, "inflammatory diseases" refers to diseases, disorders, and conditions that are mediated by BET inhibition. Exemplary inflammatory diseases, include, but are not limited to, arthritis, asthma, dermatitis, psoriasis, cystic fibrosis, post transplantation late and chronic solid organ rejection, multiple sclerosis, systemic lupus erythematosus, inflammatory bowel diseases, autoimmune diabetes, diabetic retinopathy, diabetic nephropathy, diabetic vasculopathy, ocular inflammation, uveitis, rhinitis, ischemia- reperfusion injury, post-angioplasty restenosis, chronic obstructive pulmonary disease (COPD), glomerulonephritis, Grave's disease, gastrointestinal allergies, conjunctivitis, atherosclerosis, coronary artery disease, angina, and small artery disease.

[0035] As used herein, "cancer" refers to diseases, disorders, and conditions that are mediated by BET inhibition. Exemplary cancers, include, but are not limited to, chronic lymphocytic leukemia and multiple myeloma, follicular lymphoma, diffuse large B cell lymphoma with germinal center phenotype, Burkitt's lymphoma, Hodgkin's lymphoma, follicular lymphomas and activated, anaplastic large cell lymphoma, neuroblastoma and primary neuroectodermal tumor, rhabdomyosarcoma, prostate cancer, breast cancer, NMC (NUT-midline carcinoma), acute myeloid leukemia (AML), acute B lymphoblastic leukemia (B- ALL), Burkitt's lymphoma, B-cell lymphoma, melanoma, mixed lineage leukemia, multiple myeloma, pro-myelocytic leukemia (PML), non-Hodgkin's lymphoma, neuroblastoma, medulloblastoma, lung carcinoma (NSCLC, SCLC), glioblastoma, gastric cancer, cervical cancer, ovarian cancer, bladder cancer, and colon carcinoma.

[0036] As used herein, the term "hydrate" refers to a crystal form with either a stoichiometric or non-stoichiometric amount of water incorporated into the crystal structure.

[0037] The term "pharmaceutically acceptable carrier" as used herein refers to any and all solvents, dispersion media, coatings, isotonic and absorption delaying agents, and the like, that are compatible with pharmaceutical administration. The use of such media and agents for pharmaceutically active substances is well known in the art. The compositions may also contain other active compounds providing supplemental, additional, or enhanced therapeutic functions. [0038] The disclosure also includes "deuterated analogs" of a mesylate salt/co crystal of Compound I Form I as described herein. A deuterated analog of Compound I Form I includes analogs in which one or more hydrogen atoms on a mesylate salt/co crystal of Compound I Form I has been replaced by deuterium. Deuterated analogs of a mesylate salt/co crystal of Compound I Form I may exhibit greater metabolic stability, increased half- life under physiological conditions, and/or improved therapeutic index. Deuterated analogs of a mesylate salt/co crystal of Compound I Form I may be made by substituting a readily available isotopically labeled reagent for a non-labeled reagent in any process for preparing Compound I.

Exemplary Embodiments of the Invention

[0039] As summarized above, the present invention provides a mesylate salt/co crystal of l-benzyl-6-(3,5-dimethylisoxazol-4-yl)-N-methyl-lFI-imidazo[4,5-b]pyridine-2- amine in crystalline Form I (Compound I Form I).

[0040] In one embodiment, the mesylate salt/co-crystal of Compound I Form I is characterized by an X-ray powder diffractogram (XRPD) comprising peak, in terms of 2-theta, at about 16.9 ± 2.0 degrees, as determined on a diffractometer using Cu-K_a radiation tube.

[0041] In one embodiment, the mesylate salt/co-crystal of Compound I Form I is characterized by an X-ray powder diffractogram (XRPD) comprising one or more peaks, in terms of 2-theta, at 8.4 ± 0.2, 10.6 ± 0.2, 11.7 ± 0.2, 14.5 ± 0.2, 15.3 ± 0.2, 16.9 ± 0.2, 18.2 ± 0.2, 19.0 ± 0.2, 19.9 ± 0.2, 20.5 ± 0.2, 22.6 ± 0.2, 23.8 ± 0.2, 24.5 ± 0.2, and 27.6 ± 0.2 degrees, as determined on a diffractometer using Cu-K_a radiation tube.

[0042] In one embodiment, the mesylate salt/co-crystal of Compound I Form I is characterized by an X-ray powder diffractogram (XRPD) comprising of three or more peaks, in terms of 2-theta, at 8.4 ± 0.2, 10.6 ± 0.2, 11.7 ± 0.2, 14.5 ± 0.2, 15.3 ± 0.2, 16.9 ± 0.2, 18.2 ± 0.2, 19.0 ± 0.2, 19.9 ± 0.2, 20.5 ± 0.2, 22.6 ± 0.2, 23.8 ± 0.2, 24.5 ± 0.2, and 27.6 ± 0.2 degrees, as determined on a diffractometer using Cu-K_a radiation tube.

[0043] In one embodiment, the mesylate salt/co-crystal of Compound I Form I is characterized by an X-ray powder diffractogram (XRPD) comprising of six or more peaks, in terms of 2-theta, at 8.4 ± 0.2, 10.6 ± 0.2, 11.7 ± 0.2, 14.5 ± 0.2, 15.3 ± 0.2, 16.9 ± 0.2, 18.2 ± 0.2, 19.0 ± 0.2, 19.9 ± 0.2, 20.5 ± 0.2, 22.6 ± 0.2, 23.8 ± 0.2, 24.5 ± 0.2, and 27.6 ± 0.2 degrees, as determined on a diffractometer using Cu-K_a radiation tube.

[0044] In one embodiment, the mesylate salt/co-crystal of Compound I Form I is characterized by an X-ray powder diffractogram (XRPD) comprising of nine or more peaks, in terms of 2-theta, at 8.4 ± 0.2, 10.6 ± 0.2, 11.7 ± 0.2, 14.5 ± 0.2, 15.3 ± 0.2, 16.9 ± 0.2, 18.2 ± 0.2, 19.0 ± 0.2, 19.9 ± 0.2, 20.5 ± 0.2, 22.6 ± 0.2, 23.8 ± 0.2, 24.5 ± 0.2, and 27.6 ± 0.2 degrees, as determined on a diffractometer using Cu-K_a radiation tube.

[0045] In one embodiment, the mesylate salt/co-crystal of Compound I Form I is characterized by an X-ray powder diffractogram (XRPD) comprising peaks, in terms of 2- theta, at 8.4 ± 0.2, 10.6 ± 0.2, 11.7 ± 0.2, 14.5 ± 0.2, 15.3 ± 0.2, 16.9 ± 0.2, 18.2 ± 0.2, 19.0 ± 0.2, 19.9 ± 0.2, 20.5 ± 0.2, 22.6 ± 0.2, 23.8 ± 0.2, 24.5 ± 0.2, and 27.6 ± 0.2 degrees, as determined on a diffractometer using Cu-K_a radiation tube.

[0046] In one embodiment, the mesylate salt/co-crystal of Compound I Form I is characterized by an X-ray powder diffractogram (XRPD) pattern substantially as shown in Figure 1, as determined on a diffractometer using Cu-K_a radiation tube.

[0047] In one embodiment, the mesylate salt/co-crystal of Compound I Form I is characterized by a differential scanning calorimetry (DSC) thermogram pattern with an endothermic peak at a temperature of about 207 ± 0.2 °C.

[0048] In one embodiment, the mesylate salt/co-crystal of Compound I Form I is characterized by a differential scanning calorimetry (DSC) thermogram pattern substantially as shown in Figure 2.

[0049] In one embodiment, the mesylate salt/co-crystal of Compound I Form I is characterized by a thermogravimetric analysis (TGA) thermogram substantially as shown in Figure 3.

[0050] The present invention also provides at least one process for making a crystalline mesylate salt/co-crystal of Compound I Form I by crystallization from a solvent or mixture of solvents selected from: Ethanol, water, acetone, acetonitrile, 1-butanol, ethyl acetate, isopropyl acetate, 1,4-dioxane, isopropyl alcohol (IPA), methyl ethyl ketone (MEK), methyl iso-butyl ketone (MIBK), n-heptane, methyl tert-butyl ether (MTBE), and dimethylformamide (DMF), using slurries, evaporation, cooling, and precipitation with anti solvents.

[0051] The present invention also provides, in one embodiment, pharmaceutical compositions comprising crystalline mesylate salt/co crystal of Compound I Form I as described herein.

[0052] In one embodiment, the pharmaceutical composition comprises a mesylate salt/co crystal of Compound I Form I and at least one pharmaceutical acceptable carrier.

[0053] In one embodiment, the pharmaceutical composition comprises a mesylate salt/co-crystal of Compound I, wherein at least 75% is Form I. [0054] In one embodiment, the pharmaceutical composition comprises a mesylate salt/co-crystal of Compound I, wherein at least 90% is Form I.

[0055] In one embodiment, the pharmaceutical composition comprises a crystalline mesylate salt/co-crystal of Compound I, wherein at least 95% is Form I.

[0056] In one embodiment, the pharmaceutical composition comprises a crystalline mesylate salt/co-crystal of Compound I, wherein at least 97% is Form I.

[0057] In one embodiment, the pharmaceutical composition comprises a crystalline mesylate salt/co-crystal of Compound I, wherein at least 99% is Form I.

[0058] The present invention also provides, in one embodiment, a therapeutically effective amount of a mesylate salt/co crystal of Compound I Form I that modulates or inhibits the activity of BET bromodomain-containing proteins such as BRD2, BRD3, BRD4, and BRDT have the potential to cure, treat, or improve the lives of subjects suffering from diseases mediated by bromodomain-containing proteins, such as certain cancers, inflammatory diseases, and cardiovascular diseases.

[0059] One embodiment is directed to a method of treating a disease that is mediated, at least in part, by BET bromodomain-containing proteins in a subject in need thereof, comprising administrating a therapeutically effective amount of a mesylate salt/co crystal of Compound I Form I.

[0060] In one embodiment, the disease is selected from cancers, inflammatory diseases, and cardiovascular diseases.

[0061] In one embodiment, the disease is a cancer, including B-acute lymphocytic leukemia, Burkitt's lymphoma, diffuse large cell lymphoma, multiple myeloma, primary plasma cell leukemia, lung cancer, bladder cancer, breast cancer, cervical cancer, colon cancer, gastric cancer, glioblastoma, prostate cancer, ovarian cancer, and neuroblastoma.

[0062] In one embodiment, the disease is prostate cancer.

[0063] In one embodiment, the disease is castration-resistant prostate cancer.

[0064] In one embodiment, the disease is breast cancer.

[0065] In one embodiment, the disease is triple-negative breast cancer.

[0066] In one embodiment, the disease is estrogen-receptor positive breast cancer.

[0067] In one embodiment, the subject is a human.

[0068] When treating a disease that is, at least in part, mediated by BET bromodomain-containing proteins, the subject may benefit from combination drug treatment. For example, a mesylate salt/co-crystal of Compound I Form I as described herein may be combined with one or more therapeutic agents in a single composition or in separately administered compositions that may be administered simultaneously, sequentially, or pursuant to a specified treatment regimen.

[0069] In one embodiment, a mesylate salt/co-crystal of Compound I Form I as described herein may be administered sequentially with an additional therapeutic agent(s). Sequentially means that the mesylate salt/co-crystal of Compound I and the additional therapeutic agent(s) is (are) administered with a time separation of a few seconds (for example 15 sec., 30 sec., 45 sec., 60 sec. or less), several minutes (for example 1 min., 2 min., 5 min. or less, 10 min. or less, 15 min. or less), 1-8 hours, 1-7 days, or 1-4 weeks. When administered sequentially, the mesylate salt/co-crystal of Compound I Form I and the additional therapeutic agent(s) may be administered in two or more administrations, and contained in separate compositions or dosage forms, which may be contained in the same or different package or packages.

[0070] In one embodiment, a mesylate salt/co-crystal of Compound I Form I may be combined with one or more therapeutic agent(s) used to treat cancer.

[0071] In one embodiment, a mesylate salt/co-crystal of Compound I Form I, as described herein, may be combined with one or more therapeutic agent(s) used to treat cancer.

[0072] In one embodiment, a mesylate salt/co-crystal of Compound I Form I may be combined with a therapeutic agent selected from an androgen receptor antagonist, an androgen synthesis inhibitor, an aromatase inhibitor, a selective estrogen receptor modulator, a selective estrogen down-regulator, a poly ADP ribose polymerase (PARP) inhibitor, or an immunotherapeutic agent.

[0073] In one embodiment, a mesylate salt/co-crystal of Compound I Form I may be combined with a therapeutic agent selected from Abiraterone (Zytiga), Enzalutamide (Xtandi), Apalutamide (ARN-509, Erleada), Darolutamide, Fulvestrant, Exemestane,

Talazoparib, Olaperib, Veliparib, Rucaparib, Talazoparib, Niraparib, Pembrolizumab, Nivolumab, Durvalumab, and Rituximab.

EXAMPLES

[0074] The XRPD patterns of Compound I salts/crystals were obtained on a Bruker instrument D8 advance Diffractometer or similar, using mostly the following settings: 40 kV, 40 mA, Ka = 1.54179 A (Cu-Ka radiation tube), scan scope 4 to 40 deg. 2 theta, 15 rpm, 10 deg./min. The DSC analysis was conducted on a TA instrument Q2000 differential scanning calorimeter from 30-300 °C at 10 °C/min. TH E TGA analysis was conducted on a TA instrument Q5000IR thermogravimetric analyzer from ambient temperature to 300 °C at 10 °C/min.

Example 1: Synthesis of Compound I

Step A: Synthesis of 5-bromo-N³-(phenylmethylene)pyridine-2, 3-diamine (Compound B)

[0075] Starting material A was dissolved in methanol and acetic acid. The solution was cooled to 0-5 °C and benzaldehyde was added dropwise. Once the reaction was complete, process water and a NaHCOs solution was added dropwise, keeping the temperature low (0-5 °C). The solid was filtered off and washed with methanol/water 1:1, followed by drying, leaving Compound B in 94% yield and +99% purity by HPLC. ¹H-NM R (DMSO-d₆): d 8.75 (1H), 8.04 (2H), 7.93 (1H), 7.65 (1H), 7.50-7.60 (3H).

Step B: Synthesis of N³-benzyl-5-bromopyridine-2, 3-diamine (Compound C)

[0076] Compound B was dissolved in ethanol and NaHB4 was added in portions keeping the temperature between 15-25 °C. The reaction mixture was stirred for 8-15 h until the reaction was complete as monitored by HPLC. A HCI solution was added, adjusting pH to 6-7, followed by process water, keeping the temperature between 15-25 °C. The mixture was stirred for 1-5 h, filtered and washed with an ethanol/water mixture. Following drying at ~60 °C for 15-20 h, Compound C was obtained. ¹H-NM R (DMSO-d_s): d 7.2-7.4 (6 H), 6.55 (1 H), 5.70-5.83 (3 H), 4.30 (2 H). Step C: Synthesis of N³-benzyl-5-(3,5-dimethyl-l,2-oxazol-4-yl)pyridine-2,3- diamine (Compound D)

[0077] Compound C, Compound G, and potassium phosphate tribasic trihydrate were mixed followed by addition of 1,4-Dioxane and process water. The resulting mixture was thoroughly purged with nitrogen. Tetrakis(triphenylphosphine)palladium(0) was added and the mixture was heated to >90°C until the ratio of Compound C to Compound D was not more than 1%. After cooling, the reaction mixture was filtered, the solid washed with 1,4- dioxane and then concentrated. Process water was added and the mixture was stirred until the amount of Compound D remaining in the mother liquors was not more than 0.5%. Compound D was isolated by filtration and sequentially washed with 1,4-dioxane/water and t-butylmethyl ether. The wet cake was mixed in methylene chloride and silica gel. After stirring, the mixture was filtered then concentrated. The mixture was cooled and t-butylmethyl ether was added. The product was isolated by filtration and dried until the methylene chloride, t-butylmethyl ether, and moisture levels are not more than 0.5%. ¹H- NMR (DMSO-d₆): d 7.30-7.45 (4 H), 7.20-7.25 (2 H), 6.35 (1 H), 5.65-5.80 (3 H), 4.30-4.40 (2 H), 2.15 (3 H), 1.95 (3 H).

Step D: Synthesis of l-benzyl-6-(3,5-dimethyl-l,2-oxazol-4-yl)-3H-imidazo[4,5- b]pyridin-2-one (Compound E)

[0078] Carbonyldiimidazole solid was added to a stirring mixture of Compound D and dimethylsulfoxide. The mixture was heated until the ratio of Compound D to Compound E was NMT 0.5%. The mixture was cooled and process water was added over several hours. The resulting mixture was stirred at ambient temperature for at least 2 h. The product was isolated by filtration and washed with process water. The dimethylsulfoxide was verified to be NMT 0.5% before drying using heat and vacuum. Drying was complete when the moisture level was NMT 0.5%, leaving Compound E. ¹H-NMR (DMSO-d_s): d 11.85 (1 H), 7.90 (1 H), 7.20-7.45 (6 H), 5.05 (2 H), 3.57 (3 H), 2.35 (3 H), 2.15 (3 H).

Step E: Synthesis of 4-[l-benzyl-2-chloro-lH-imidazo[4,5-b]pyridine-6-yl]-3,5- dimethyl-1, 2-oxazole (Compound F)

[0079] Compound E and phosphorus oxychloride were mixed and then treated with diisopropylethyl amine (DIPEA), which can be added dropwise. The resulting mixture was heated for several hours, cooled, and sampled for reaction completion. If the ratio of Compound E to Compound F was not more than 0.5% then the reaction was complete. Otherwise, the reaction was heated for additional time and sampled as before. After the reaction was complete, the mixture was concentrated then cooled. Ethyl acetate was added and the mixture was concentrated under vacuum several times. Ethyl acetate (EtOAc) was added to the concentrate, the mixture was cooled and then added to aqueous sodium bicarbonate. The organic phase was separated and the organic layer was washed with aqueous sodium bicarbonate and then water. The organic phase was concentrated, ethyl acetate was added, and the mixture was concentrated to assure that the moisture level was not more than 0.2%. The mixture in ethyl acetate was decolorized with carbon. The mixture was concentrated and n-heptane was added. The product was isolated by filtration and dried under vacuum. Drying was complete when residual moisture, ethyl acetate, and n- heptane were not more than 0.5%. ¹H-NMR (MeOH-d₄): d 8.40 (1 H), 7.90 (1 H), 7.25-7.45 (5 H), 5.65 (2 H), 2.37 (3 H), 2.22 (3 H).

Step F: Synthesis of l-benzyl-6-(3,5-dimethyl-l,2-oxazol-4-yl)-N-methyl-lH- imidazo[4,5-b]pyridine-2-amine (Compound I)

ompoun [0080] Compound F was mixed with methylamine in tetrahydrofuran (THF) and stirred at ambient temperature until the ratio of Compound F to Compound I was NMT 0.1% by HPLC. After reaction completion, the mixture was concentrated under vacuum, process water added, and the product isolated by filtration. The filter cake was washed with process water. The wet cake was dissolved in hydrochloric acid and the resulting solution was washed with methylene chloride to remove impurities. The aqueous solution was neutralized with a sodium hydroxide solution and Compound I was isolated by filtration, washed with process water, and dried under vacuum. If necessary, to remove any remaining hydrochloric acid, the dried material can be dissolved in ethanol, treated with a solution of sodium hydroxide in ethanol, followed by addition of process water to precipitate the product. Compound I was isolated by filtration, washed with process water, and dried. ¹H- NMR (DMSO-de): d 7.96 (d, 1H, J=2.0 Hz), 7.42 (d, 1H, J=2.0 Hz), 7.37 (q, 1H, J=4.2 Hz), 7.32 (m, 2H), 7.26 (m, 1H), 7.24 (m, 2H), 5.30 (s, 2H), 3.00 (d, 3H, 4.5 Hz), 2.34 (s, 3H), 2.16 (s, 3H). ¹³C-NM R (DMSO-de): d 164.8, 158.4, 157.7, 156.0, 141.1, 136.4, 128.6 (2C), 127.5, 127.4, 127.2 (2C), 115.8, 114.2 (2C), 44.5, 29.3, 11.2, 10.3.

Example 2: Crystalline phosphate of Compound I Form A

[0081] About 5 g of Compound I was dissolved in acetone (170 mL) and a solution of phosphoric acid in acetone (10 mL, 190.4 mg/mL) was added, according to a 1:1 molar ratio. The mixture was shaken at room temperature for 4 days. The formed solid

(Phosphate of Compound I Form A) was isolated, dried, and characterized.

[0082] The phosphate salt/co-crystal of Compound I Form A was characterized by XRPD comprising the following peaks, in terms of 2-theta, at 8.3± 0.2, 11.4± 0.2, 12.1± 0.2,

14.6± 0.2, 15.3± 0.2, 16.4± 0.2, 17.7± 0.2, 18.6± 0.2, 19.9± 0.2, 22.8± 0.2, 24.2± 0.2, 24.4±

0.2, 27.2± 0.2, and 28.8± 0.2 (Figure 4).

[0083] The phosphate salt/co-crystal of Compound I Form A was characterized by DSC having an endothermic peak at a temperature of about 225 °C (Figure 5).

[0084] The phosphate salt/co-crystal of Compound I Form A was characterized by TGA, having a thermogram as shown in Figure 6.

[0085] The approximate solubility tests of the phosphate salt/crystal of Compound I Form A were conducted in different solvents at ambient temperature (kinetic solubility). These tests showed that the phosphate salt/co-crystal of Compound I Form A demonstrated very limited solubility in all solvents tested: methanol, ethanol, isopropyl alcohol, 1-butanol, acetonitrile (ACN), acetone, M EK, M IBK, ethyl acetate, isopropyl acetate, MTBE, THF, 2-Me THF, heptane, 1,4-dioxane, Me0H-H₂0 (95:5), THF-H₂0 (95:5), ACN-H₂0 (95:5), and acetone- H₂0 (95:5).

[0086] Slurry conversion experiments were conducted at 40 °C in the different solvent systems. About 50 mg of the phosphate salt/co-crystal of Compound I Form A was suspended in 1.2 mL of solvent in a 1.5 mL vial separately. After shaking the suspension for 48 h protected from light, the residuals were isolated for XRPD analysis. Form conversion was observed in most solvents, including water.

Example 3: Crystalline mesylate of Compound I Form I

[0087] About 5 g of Compound I was dissolved in ethanol (115 mL) and a solution of methanesulfonic acid in ethanol (10 mL, 158.7 mg/mL) was added, according to a 1:1 molar ratio. The mixture was shaken at 50 °C for 2 h before concentrated to half volume and stirred overnight. The formed solid (mesylate salt/co-crystal of Compound I Form I) was isolated, dried, and characterized.

[0088] The mesylate salt/co crystal of Compound I Form I was also obtained from other solvents and solvent mixtures, including acetone and acetonitrile.

[0089] The mesylate salt/co crystal of Compound I Form I was characterized by XRPD comprising the following peaks, in terms of 2-theta, at 8.4 ± 0.2, 10.6 ± 0.2, 11.7 ± 0.2, 14.5 ± 0.2, 15.3 ± 0.2, 16.9 ± 0.2, 18.2 ± 0.2, 19.0 ± 0.2, 19.9 ± 0.2, 20.5 ± 0.2, 22.6 ± 0.2, 23.8 ± 0.2, 24.5 ± 0.2, and 27.6± 0.2 degrees, as determined on a diffractometer using Cu-K_a radiation tube (Figure 1).

[0090] The mesylate salt/co crystal of Compound I Form I was characterized by DSC having an endothermic peak at a temperature of about 207 °C (Figure 2).

[0091] The mesylate salt/co crystal of Compound I Form I was characterized by TGA, having a thermogram as shown in Figure 3, confirming that Compound I Form I is an anhydrous form.

[0092] The approximate solubility tests of the mesylate salt/co-crystal of

Compound I Form I were conducted in the same solvents used to evaluate the phosphate salt/cocrystal of Compound I Form A at ambient temperature (kinetic solubility). The mesylate salt/co-crystal of Compound I Form I showed excellent solubility in several solvents, including methanol, ethanol, and all solvent systems containing about 5% water.

[0093] Slurry conversion experiments were conducted at 40 °C in different solvent systems. About 50 mg of the mesylate salt/co-crystal of Compound I Form I was suspended in 1.2 mL of solvent in a 1.5 mL vial separately. After shaking the suspension for 48 h protected from light, the residuals were isolated for XRPD analysis. No new forms were observed for the mesylate of Compound I, confirming that the Form I is highly

thermodynamically stable.

[0094] The solubility of both the mesylate salt/co-crystal of Compound I Form I and the phosphate salt/co-crystal of Compound I Form A was evaluated in water and simulated gastric fluid (SGF). About 50 mg of the mesylate salt/co-crystal of Compound I Form I or the phosphate salt/co-crystal of Compound I Form A and 0.5 mL of media (either water or SGF) were added to a 2 mL glass vial. The mixture was shaken at 25 °C for 24 h. After 24 the slurry was filtered and analyzed. The initial and final pH was measured by pH meter. The filtrate was analyzed by H PLC. The results (Table 1) confirms the poor solubility of the phosphate salt/co-crystal of Compound I Form A and the substantially superior solubility of the mesylate salt/co-crystal of Compound I Form I in both water and SGF.

Table 1: Solubility summary of phosphate, maleate and mesylate in water and SGF

¹ Solubility was determined after 24 hours at 25 °C by HPLC;

[0095] To assess the crystalline stability during milling, the following experiment was performed. A sample of the mesylate salt/co-crystal of Compound I Form I was grounded using a mortar and pestle (1-3 min) (grinding method) and the solid was analyzed by XRPD. No form change was observed for the mesylate of Compound I Form I.

[0096] The chemical stability of the mesylate salt/co-crystal of Compound I Form I was also assessed at three conditions (60 °C with no controlled humidity for 2 weeks; 60 °C/75% RH for 2 weeks; and 40 °C/75%RFI for six months). The mesylate of Compound I Form I was shown to be chemically stable without any form transformation for the duration of the test period.

Claims

CLAIMS What is claimed is:

1. A solid mesylate salt/co-crystal of Compound I:

(Compound I) in substantially crystalline Form I.

2. The solid form of claim 1 which is an anhydrate.

3. The solid mesylate salt/co-crystal of Compound I, characterized by an XRPD peak, in terms of 2-theta, at about 16.9 degrees, as determined on a diffractometer using Cu-K_a radiation tube.

4. The solid mesylate salt/co-crystal of any one of claim 1-3, having three or more

characteristic XRPD peaks, in terms of 2-theta, selected from 8.4 ± 0.2, 10.6 ± 0.2, 11.7 ± 0.2, 14.5 ± 0.2, 15.3 ± 0.2, 16.9 ± 0.2, 18.2 ± 0.2, 19.0 ± 0.2, 19.9 ± 0.2, 20.5 ± 0.2, 22.6 ± 0.2, 23.8 ± 0.2, 24.5 ± 0.2, and 27.6± 0.2 degrees, as determined on a diffractometer using Cu-K_a radiation tube.

5. The solid mesylate salt/co-crystal of any one of claim 1-3, having an XRPD pattern

substantially as shown in Figure 1.

6. A solid mesylate salt/co-crystal of Compound I, having Form I and further characterized as anhydrous.

7. The solid mesylate salt/co-crystal of any one of claim 1-6, having a DSC thermogram characterized by an endothermic peak at a temperature of about 207 °C.

8. The solid mesylate salt/co-crystal of any one of claim 1-6, having a DSC thermogram substantially as shown in Figure 2.

9. The solid mesylate salt/co-crystal of any one of claim 1-8, having a TGA thermogram substantially as shown in Figure 3.

10. The pharmaceutical composition comprising a solid form of any one of claims 1-9 and at least one pharmaceutically acceptable carrier.

11. A method of treating a cancer, comprising administrating to a subject in need of such treatment a therapeutically effective amount of a solid mesylate salt/co-crystal of any one of claims 1-9 or the pharmaceutical composition of claim 10.

12. The method of claim 11, wherein the cancer is B-acute lymphocytic leukemia, Burkitt's lymphoma, diffuse large cell lymphoma, multiple myeloma, primary plasma cell leukemia, lung cancer, bladder cancer, breast cancer, cervical cancer, colon cancer, gastric cancer, glioblastoma, prostate cancer, ovarian cancer, and neuroblastoma.

13. The method of claim 12, wherein the cancer is prostate cancer.

14. The method of claim 12, wherein the cancer is castration-resistant prostate cancer.

15. The method of claim 12, wherein the cancer is breast cancer.

16. The method of claim 12, wherein the cancer is triple-negative breast cancer.

17. The method of claim 12, wherein the cancer is estrogen-receptor positive breast cancer.

18. A method of treating an inflammatory disease, comprising administrating to a subject in need of such treatment a therapeutically effective amount of a solid mesylate salt/co crystal of any one of claims 1-9 or the pharmaceutical composition of claim 10.

19. A method of treating a cardiovascular disease, comprising administrating to a subject in need of such treatment a therapeutically effective amount of a solid mesylate salt/co crystal of any one of claims 1-9 or the pharmaceutical composition of claim 10.

20. The method of any one of claims 11-19, wherein the subject is a human.

21. A method of preparing the solid mesylate salt/co-crystal of Compound I of any one of claims 1-10 comprising dissolving Compound I in ethanol and methanesulfonic acid in a 1:1 molar ratio.

22. A method of preparing the solid mesylate salt/co-crystal of Compound I of any one of claims 1-10 comprising dissolving Compound I in acetone and acetonitrile.