• Originator MyoKardia
• Class Cardiovascular therapies; Small molecules
• Mechanism of Action Myosin inhibitors

• Orphan Drug Status Yes – Hypertrophic cardiomyopathy

Highest Development Phases

• Phase III Hypertrophic cardiomyopathy

Most Recent Events

• 30 May 2018 Phase-III clinical trials in Hypertrophic cardiomyopathy in USA (PO) (NCT03470545)
• 08 May 2018 MyoKardia plans a long-term extension (LTE) trial of patients who complete the phase III EXPLORER-HCM or the phase II MAVERICK-HCM trial for Hypertrophic cardiomyopathy by the end of 2018
• 26 Apr 2018 MyoKardia initiates the PIONEER-OLE trial (an extension trial of phase II PIONEER trial) for Hypertrophic cardiomyopathy in USA (PO) (NCT03496168)

Example 1 Preparation of (S)-3-Isopropyl-6-((1-phenylethyl)amino)pyrimidine-2,4(1H,3H)-dione

Compound 1.1. Isopropylurea. To a stirred solution of isopropylamine (15.3 g, 0.258 mol, 1.0 equiv) in CH₂Cl₂ (200 mL) under argon at 0° C. was added dropwise trimethylsilyl isocyanate (30 g, 0.26 mol, 1.0 equiv). The resulting mixture was allowed to reach ambient temperature and stirred overnight. After cooling to 0° C., CH₃OH (100 mL) was added dropwise. The resulting solution was stirred for 2 hours (h) at room temperature and then concentrated under reduced pressure. The crude residue was recrystallized from CH₃OH:Et₂O (1:20) to yield 15.4 g (58%) the title compound as a white solid. LC/MS: m/z (ES+) 103 (M+H)⁺.

Compound 1.2. 1-Isopropyl barbituric acid. To a stirred solution of 1.1 (14.4 g, 0.14 mol, 1.00 equiv) in CH₃OH (500 mL) were added dimethyl malonate (19.55 g, 0.148 mol, 1.05 equiv) and sodium methoxide (18.9 g, 0.35 mol, 2.50 equiv). The resulting mixture was stirred overnight at 65° C. After cooling to ambient temperature and then to 0° C., the pH was carefully adjusted to 3 using aqueous concentrated HCl. The resulting mixture was concentrated under reduced pressure. The residue was taken up in EtOH (200 mL) and filtered. The filtrate was concentrated under reduced pressure and the residue was purified by silica gel column chromatography using CH₂Cl₂/CH₃OH (20:1) as eluent to yield 16.8 g (50%) of the title compound as a white solid. LC/MS: m/z (ES+) 171 (M+H)⁺. ^{1 1}H-NMR (300 MHz, d₆-DMSO): δ 11.19 (s, 1H), 4.83 (m, 1H), 3.58 (s, 2H), 1.32 (d, J=6.0 Hz, 6H).

Compound 1.3. 6-chloro-3-isopropylpyrimidine-2,4(1H,3H)-dione. To a 100-mL round-bottom flask containing compound 1.2 (11.4 g, 66.99 mmol, 1.00 equiv) under argon were added triethylbenzylammonium chloride (21.3 g, 93.51 mmol, 1.40 equiv) and POCl₃ (30 mL). The resulting mixture was stirred overnight at 50° C. After cooling to room temperature, the mixture was concentrated under reduced pressure. The residue was dissolved in CH₂Cl₂ (150 mL) followed by slow addition of H₂O (100 mL). The phases were separated and the organic layer was washed with H₂O (100 mL), dried with anhydrous Na₂SO₄, and concentrated under reduced pressure. The crude residue was purified by silica gel column chromatography using EtOAc/petroleum ether (1:1) as eluent to yield 5.12 g (40%) of the title compound as a light yellow solid. ¹H-NMR (300 MHz, d₆-DMSO): δ 12.22 (s, 1H), 5.88 (s, 1H), 4.95 (m, 1H), 1.34 (d, J=6.0 Hz, 6H).

Compound 1. (S)-3-Isopropyl-6-((1-phenylethyl)amino)pyrimidine-2, 4(1H,3H)-dione. To a solution of 6-chloro-3-isopropylpyrimidine-2,4(1H,3H)-dione (1.3, 1.0 g, 5.31 mmol) in 1,4-dioxane (20 mL) was added (S)-α-methylbenzylamine (Sigma-Aldrich, 1.43 g, 11.7 mmol, 2.2 equiv). The reaction mixture was stirred at 80° C. for 24 h. After cooling to ambient temperature, the mixture was concentrated under reduced pressure. The residual was taken up in EtOAc (70 mL) and washed with aqueous 1N HCl (2×50 mL) and brine (40 mL). The organic layer was dried with anhydrous Na₂SO₄ and then concentrated under reduced pressure to half the original volume to yield a precipitate. Hexane (20 mL) was added and the mixture was stirred at room temperature. The resulting solid was collected by filtration, washed with hexane (20 mL), and dried to yield 1.0 g (69%) of the title compound as a white solid. LC/MS: m/z (ES+) 274 (M+H)⁺. ¹H-NMR (400 MHz, d₆-DMSO): δ 9.77 (s, 1H), 7.32 (m, 4H), 7.24 (m, 1H), 6.50 (d, J=6.8 Hz, 1H), 4.87 (m, 1H), 4.52 (m, 1H), 4.31 (d, J=6.8 Hz, 1H), 1.37 (m, 3H), 1.24 (m, 6H). ¹H NMR (400 MHz, CD₃OD) δ ppm 7.39-7.20 (m, 5H), 5.01 (m, 1H), 4.48 (m, 1H), 1.49 (d, J=6.7 Hz, 3H), 1.36 (m, 6H).

PATENT

https://patents.google.com/patent/US9181200/zh-CN

Genetic (heritable) hypertrophic cardiomyopathy (HCM) comprises a group of highly penetrant, monogenic, autosomal dominant myocardial diseases. HCM is caused by one or more of over 1,000 known point mutations in any one of the structural protein genes contributing to the functional unit of myocardium, the sarcomere. About 1 in 500 individuals in the general population are found to have left ventricular hypertrophy unexplained by other known causes (e.g., hypertension or valvular disease), and many of these can be shown to have HCM, once other heritable (e.g., lysosomal storage diseases), metabolic, or infiltrative causes have been excluded.

[0004] Sarcomere gene mutations that cause HCM are highly penetrant, but there is wide variability in clinical severity and clinical course. Some genotypes are associated with a more malignant course, but there is considerable variability between and even within families carrying the same mutation. Sex differences have also been noted, with male patients generally more severely affected than female patients. While many patients with HCM report minimal or no symptoms for extended periods of time, HCM is a progressive disease with a significant cumulative burden of morbidity. Symptoms of effort intolerance predominate, and can be exacerbated by exercise and other maneuvers that increase heart rate and/or decrease preload. As with many other disorders, symptoms tend to worsen with age. By far the most prevalent clinical burden for patients with HCM is exertional dyspnea, which limits their activities of daily living and can be debilitating.

[0005] Patients with HCM are often symptomatic in the absence of documented hemodynamic abnormalities like left ventricular outflow tract obstruction (with or without mitral regurgitation). Patients’ symptoms of exertional dyspnea can rapidly worsen with the onset of atrial fibrillation, a common complication of HCM that can precipitate acute pulmonary edema that increases the risk of systemic arterial thromboembolic disease, including stroke. Other adverse events associated with HCM include intolerance of hypovolemia or hypervolemia, and syncope. Concomitant coronary artery disease may confer a higher risk of acute coronary syndromes than in patients without HCM. Sudden cardiac death (SCD) in patients with HCM is both uncommon and difficult to predict but is a leading cause of non-traumatic death in young adults. For survivors of SCD, ICD placement is standard practice, and in other HCM patients risk profiling, while imprecise, is used to identify those for whom ICD placement for primary prevention is deemed prudent.

[0006] Medical therapy for HCM is limited to the treatment of symptoms and does not address the fundamental, underlying cause of disease – disruptions in normal sarcomere function. Currently available therapies are variably effective in alleviating symptoms but typically show decreased efficacy with increasing disease duration. Patients are thus empirically managed with beta-blockers, non-dihydropyridine calcium channel blockers, and/or disopyramide. None of these agents carry labeled indications for treating HCM, and essentially no rigorous clinical trial evidence is available to guide their use. Compounding this unfortunate situation is the fact that no new medical therapies for HCM have been identified for many years. For patients with hemodynamically significant outflow tract obstruction (resting gradient >30mmHg), in appropriately selected patients surgical myectomy or alcohol septal ablation is usually required to alleviate the hemodynamic obstruction. Provided are new therapeutic agents and methods that remedy the long-felt need for improved treatment of HCM and related cardiac disorders.

Example 1. Preparation of (61-3-Isopropyl-6-((1-phenylethyl) amino) pyrimidine-2, 4(1H,3H)-dione.

[0072] Compound 1.1. Isopropylurea. To a stirred solution of isopropylamine (15.3 g, 0.258 mol, 1.0 equiv) in CH₂Cl₂ (200 mL) under argon at 0 °C was added dropwise trimethylsilyl isocyanate (30 g, 0.26 mol, 1.0 equiv). The resulting mixture was allowed to reach ambient temperature and stirred overnight. After cooling to 0 °C, CH₃OH (100 mL) was added dropwise. The resulting solution was stirred for 2 hours (h) at room temperature and then concentrated under reduced pressure. The crude residue was recrystallized from CH₃OH:Et₂O (1 :20) to yield 15.4 g (58%) the title compound as a white solid. LC/MS: m/z (ES+) 103 (M+H)⁺.

[0073] Compound 1.2. 1-Isopropyl barbituric acid. To a stirred solution of 1.1 (14.4 g, 0.14 mol, 1.00 equiv) in CH₃OH (500 mL) were added dimethyl malonate (19.55 g, 0.148 mol, 1.05 equiv) and sodium methoxide (18.9 g, 0.35 mol, 2.50 equiv). The resulting mixture was stirred overnight at 65 °C. After cooling to ambient temperature and then to 0 °C, the pH was carefully adjusted to 3 using aqueous concentrated HCl . The resulting mixture was concentrated under reduced pressure. The residue was taken up in EtOH (200 mL) and filtered. The filtrate was concentrated under reduced pressure and the residue was purified by silica gel column chromatography using CH₂Cl₂/CH₃OH (20: 1) as eluent to yield 16.8 g (50%) of the title compound as a white solid. . LC/MS: m/z (ES+) 171 (M+H)⁺.^{1 1}H-NMR (300 MHz, de-DMSO): 5 11.19 (s, 1H), 4.83 (m, 1H), 3.58 (s, 2H), 1.32 (d, J = 6.0 Hz, 6H).

[0074] Compound 1.3. 6-chloro-3-isopropylpyrimidine-2,4(1H,3H)-dione. To a 100-mL round-bottom flask containing compound 1.2 (11.4 g, 66.99 mmol, 1.00 equiv) under argon were added triethylbenzylammonium chloride (21.3 g, 93.51 mmol, 1.40 equiv) and POCl₃ (30 mL). The resulting mixture was stirred overnight at 50 °C. After cooling to room temperature, the mixture was concentrated under reduced pressure. The residue was dissolved in CH₂Cl₂ (150 mL) followed by slow addition of H₂O (100 mL). The phases were separated and the organic layer was washed with H₂O (100 mL), dried with anhydrous Na₂SO₄ , and concentrated under reduced pressure. The crude residue was purified by silica gel column chromatography using EtO Ac/petroleum ether (1 : 1) as eluent to yield 5.12 g (40%) of the title compound as a light yellow solid. ¹H-NMR (300 MHz, d₆-DMSO): δ 12.22 (s, 1H), 5.88 (s, 1H), 4.95 (m, 1H), 1.34 (d, J = 6.0 Hz, 6H).

[0075] Compound 1. (S)-3-Isopropyl-6-((1-phenylethyl) amino) pyrimidine-2,

4(1H,3H)-dione. To a solution of 6-chloro-3-isopropylpyrimidine-2,4(1H,3H)-dione (1.3,

1.0 g, 5.31 mmol) in 1,4-dioxane (20 mL) was added (S)-a-methylbenzylamine (Sigma- Aldrich, 1.43 g, 11.7 mmol, 2.2 equiv). The reaction mixture was stirred at 80 °C for 24 h. After cooling to ambient temperature, the mixture was concentrated under reduced pressure. The residual was taken up in EtOAc (70 mL) and washed with aqueous IN C1 (2 x 50 mL) and brine (40 mL). The organic layer was dried with anhydrous Na₂SC”4 and then

concentrated under reduced pressure to half the original volume to yield a precipitate.

Hexane (20 mL) was added and the mixture was stirred at room temperature. The resulting solid was collected by filtration, washed with hexane (20 mL), and dried to yield 1.0 g (69%) of the title compound as a white solid. LC/MS: m/z (ES+) 274 (M+H)⁺. 1H-NMR (400 MHz, de-DMSO): δ 9.77 (s, 1H), 7.32 (m, 4H), 7.24 (m, 1H), 6.50 (d, J= 6.8 Hz, 1H), 4.87 (m,

1H), 4.52 (m, 1H), 4.31 (d, J=6.8 Hz, 1H), 1.37 (m, 3H ), 1.24 (m, 6H). 1H NMR (400 MHz, CD₃OD) δ ppm 7.39-7.20 (m, 5H), 5.01 (m, 1H), 4.48 (m, 1H), 1.49 (d, J = 6.7 Hz, 3H), 1.36 (m, 6H).

REFERENCES

1: Green EM, Wakimoto H, Anderson RL, Evanchik MJ, Gorham JM, Harrison BC, Henze M, Kawas R, Oslob JD, Rodriguez HM, Song Y, Wan W, Leinwand LA, Spudich JA, McDowell RS, Seidman JG, Seidman CE. A small-molecule inhibitor of sarcomere contractility suppresses hypertrophic cardiomyopathy in mice. Science. 2016 Feb 5;351(6273):617-21. doi: 10.1126/science.aad3456. PubMed PMID: 26912705; PubMed Central PMCID: PMC4784435.