Daclatasvir

Common name: Daclatasvir; BMS-790052; BMS 790052; Daklinza;  Daclatasvir dihydrochloride
Trademarks: Daklinza
Molecular Formula: C40H50N8O6
CAS Registry Number: 1214735-16-6; 1009119-65-6 (dihydrochloride)
CAS Name: methyl N-[(2S)-1-[(2S)-2-[5-[4-[4-[2-[(2S)-1-[(2S)-2-(methoxycarbonylamino)-3-methylbutanoyl]pyrrolidin-2-yl]-1H-imidazol-5-yl]phenyl]phenyl]-1H-imidazol-2-yl]pyrrolidin-1-yl]-3-methyl-1-oxobutan-2-yl]carbamate
Molecular Weight: 738.88
SMILES:CC(C)C(C(=O)N1CCCC1C2=NC=C(N2)C3=CC=C(C=C3)C4=CC=C(C=C4)C5=CN=C(N5)C6CCCN6C(=O)C(C(C)C)NC(=O)OC)NC(=O)OC
InChI Key: FKRSSPOQAMALKA-CUPIEXAXSA-N
InChI: InChI=1S/C40H50N8O6/c1-23(2)33(45-39(51)53-5)37(49)47-19-7-9-31(47)35-41-21-29(43-35)27-15-11-25(12-16-27)26-13-17-28(18-14-26)30-22-42-36(44-30)32-10-8-20-48(32)38(50)34(24(3)4)46-40(52)54-6/h11-18,21-24,31-34H,7-10,19-20H2,1-6H3,(H,41,43)(H,42,44)(H,45,51)(H,46,52)/t31-,32-,33-,34-/m0/s1
Activity: Treatment of Hepatitis C; HCV Drug; Treatment of HCV; Inhibitor of NS5A
Status: Launched 2014 (EU, Japan)
Originator: Bristol-Myers Squibb

Daclatasvir synthesis: WO2009020828A1

Procedure:

Step a: A 1 L, 3 -neck round bottom flask, fitted with a nitrogen line, overhead stirrer and thermocouple, was charged with 20 g (83.9 mmol, 1 equiv) 1,1'-(biphenyl-4,4'-diyl)diethanone, 200 mL Dichloromethane and 8.7 mL (27.1g, 169.3 mmol, 2.02 equiv) bromine. The mixture was allowed to stir under nitrogen for about 20 hours under ambient conditions. The resulting slurry was charged with 200 mL Dichloromethane and concentrated down to about 150 mL via vacuum distillation. The slurry was then solvent exchanged into THF to a target volume of 200 mL via vacuum distillation. The slurry was cooled to 20-25 ⁰C over 1 hour and allowed to stir at 20-25 ⁰C for an additional hour. The off-white crystalline solids were filtered and washed with 150 mL Dichloromethane. The product was dried under vacuum at 60 0C to yield 27.4 g (69.2 mmol, 82%) of the desired product: 1H NMR (400 MHz, CDCl3) d 7.95-7.85 (m, 4H), 7.60-7.50 (m, 4H), 4.26 (s, 4H); 13C NMR 100 MHz, CDCl3) d 191.0, 145.1, 133.8, 129.9, 127.9, 30.8; IR (KBr, cm-1) 3007, 2950, 1691, 1599, 1199; Anal calcd for C16H12Br2O2: C, 48.52; H, 3.05; Br, 40.34. Found: C, 48.53; H, 3.03; Br, 40.53. HRMS calcd for C16H12Br2O2 (M + H; DCI+): 394.9282. Found: 394.9292. mp 224-226 0C.

Step b: A 500 mL jacketed flask, fitted with a nitrogen line, thermocouple and overhead stirrer, was charged with 20 g (50.5 mmol, 1 equiv) of Compound 2, 22.8 g (105.9 moles, 2.10 equiv) 1-(tert-butoxycarbonyl)-L-proline and 200 mL acetonitrile. The slurry was cooled to 20 ⁰C followed by the addition of 18.2 mL (13.5 g, 104.4 mmol, 2.07 equiv) DIPEA. The slurry was warmed to 25 ⁰C and allowed to stir for 3 hours. The resulting clear, organic solution was washed with 3 x 100 mL 13 wt% aqueous NaCl. The rich acetonitrile solution was solvent exchanged into toluene (target volume = 215 mL) by vacuum distillation until there was less than 0.5 vol% acetonitrile.

Step c: The toluene solution of Compound 3 was charged with 78 g (1.011 moles, 20 equiv) ammonium acetate and heated to 95-100 ⁰C. The mixture was allowed to stir at 95-100 ⁰C for 15 hours. After reaction completion, the mixture was cooled to 70- 80 ⁰C and charged with 7 mL acetic acid, 40 mL n-butanol, and 80 mL of 5 vol% aqueous acetic acid. The resulting biphasic solution was split while maintaining a temperature > 50 ⁰C. The rich organic phase was charged with 80 mL of 5 vol% aqueous acetic acid, 30 mL acetic acid and 20 mL n-butanol while maintaining a temperature > 50 ⁰C. The resulting biphasic solution was split while maintaining a temperature > 50 ⁰C and the rich organic phase was washed with an additional 80 mL of 5 vol% aqueous acetic acid. The rich organic phase was then solvent exchanged into toluene to a target volume of 215 mL by vacuum distillation. While maintaining a temperature less than 60 ⁰C, 64 mL methanol was charged. The resulting slurry was heated to 70-75 0C and aged for 1 hour. The slurry was cooled to 20-25 ⁰C over 1 hour and aged at that temperature for an additional hour. The slurry was filtered and the cake was washed with 200 mL 10:3 toluene:methanol. The product was dried under vacuum at 70 ⁰C, resulting in 19.8 g (31.7 mmol, 63%) of the desired product: 1H NMR (400 MHz, DMSO) d 13.00-11.00 (s, 2H), 7.90-7.75 (m, 4H), 7.75-7.60 (m, 4H), 7.60-7.30 (s, 2H), 4.92-4.72 (m, 2H), 3.65-3.49 (m, 2H), 3.49-3.28 (m, 2H), 2.39-2.1 (m, 2H), 2.10-1.87 (m, 6H), 1.60-1.33 (s, 8H), 1.33-1.07 (s, 10H); 13C NMR (100 MHz, DMSO-?fe) d 154.1, 153.8, 137.5, 126.6, 125.0, 78.9, 78.5, 55.6, 55.0, 47.0, 46.7, 33.7, 32.2, 28.5, 28.2, 24.2, 23.5; IR (KBr, cm-1) 2975, 2876, 1663, 1407, 1156, 1125; HRMS calcd for C36H45N6O4 (M + H; ESI+): 625.3502. Found: 625.3502. mp 190-195 0C (decomposed).

Step d: To a 250 mL reactor equipped with a nitrogen line and overhead stirrer, 25.0 g of Compound 4 (40.01 mmol, 1 equiv) was charged followed by 250 mL methanol and 32.85 mL (400.1 mmol, 10 equiv) 6M aqueous HCl. The temperature was increased to 50 ⁰C and agitated at 50 ⁰C for 5 hours. The resulting slurry was cooled to 20-25 ⁰C and held with agitation for about 18 hours. Filtration of the slurry afforded a solid which was washed successively with 100 mL 90% methanoI/water (WV) and 2 x 100 mL of methanol. The wet cake was dried in a vacuum oven at 50 ⁰C overnight to give 18.12 g (31.8 mmol, 79.4%) of the desired product.

Daclatasvir faces problems in USA

The US-FDA in 2014 issued a complete response letter for NS5A inhibitor daclatasvir saying it was unable to approve the drug because the marketing application was for its use in tandem with asunaprevir, an NS3/NS4A protease inhibitor discontinued in the US by BMS for commercial reasons. Daclatasvir is already on the market in Europe-where it is sold as Daklinza-and also in Japan where it was approved alongside asunaprevir in July as the country's first all-oral HCV therapy. However, a delay in the large US market is clearly a major setback for BMS' ambitions in hepatitis therapy.

To make the matter worse, US FDA has rescinded breakthrough therapy designation status from Bristol-Myers Squibb for Daclatasvir for the treatment of hepatitis C virus infection in Feb 2015.

References:

1. Kim, S.; et. al. Crystalline form of methyl ((1s)-1-(((2s)-2-(5-(4'-(2-((2s)-1-((2s)-2-((methoxycarbonyl)amino)-3-methylbutanoyl)-2-pyrrolidinyl)-1h-imidazol-5-yl)-4-biphenylyl)-1h-imidazol-2-yl)-1-pyrrolidinyl)carbonyl)-2-methylpropyl)carbamate dihydrochloride salt. WO2009020828A1
2. Makonen, B.; et. al. Hepatitis C Virus NS5A Replication Complex Inhibitors: The Discovery of Daclatasvir. J Med Chem 2014, 57(5), 2013–2032.
3. ClinicalTrials Phase III Daclatasvir + Sofosbuvir in Cirrhotic Subjects and Subjects Post-liver Transplant (ALLY 1). Trial ID Number NCT02032875 (AI444-215).
4. ClinicalTrials Phase III HIV/HCV Co-Infection Daclatasvir (DCV) + Sofosbuvir (SOF) (ALLY 2). Trial ID Number NCT02032888 (AI444-216).
5. ClinicalTrials Phase III Daclatasvir + Sofosbuvir for Genotype 3 Chronic HCV (ALLY 3). Trial ID Number NCT02032901 (AI444-218).

Drugs in Clinical Pipeline: Ravidasvir | NS5A Inhibitor | Treatment for Hepatitis C | IFN free Regimen

Ravidasvir [Methyl N-[(1S)-1-({(2S)-2-[5-(6-{2-[(2S)-1-{(2S)-2-[(methoxycarbonyl)amino]- 3- methylbutanoyl}pyrrolidin-2-yl]-1H-imidazol-4-yl}naphthalen-2-yl) -1H- benzimidazol- 2-yl]pyrrolidin-1-yl}carbonyl)-2-methylpropyl]carbamate] is an Nonstructural protein 5A (NS5A) inhibitor.

Ravidasvir: 2D and 3D Structure

It is an antiviral agent that is being developed as a potential treatment for hepatitis C virus infection. Ravidasvir has 50% inhibitory concentrations (EC_{50 '}s) values of 0.02-1.3 nM in replicon assays for HCV genotypes 1-7 (gt1-gt7). 

Ravidasvir was developed by Presidio Pharmaceuticals Inc, later Ascletis licensed it. Ravidasvir is in Phase II clinical trials proving interferon (IFN)-free regimen to treat chronic hepatitis C (CHC). Ascletis is now the first Chinese company to file clinical trial applications in China for an IFN-free regimen. 

IUPAC Name: Methyl N-[(1S)-1-({(2S)-2-[5-(6-{2-[(2S)-1-{(2S)-2-[(methoxycarbonyl)amino]-3-methylbutanoyl}pyrrolidin-2-yl]-1H-imidazol-4-yl}naphthalen-2-yl) -1H- benzimidazol- 2-yl]pyrrolidin-1-yl}carbonyl)-2-methylpropyl]carbamate

Common Name: PPI-668; BI 238630; ASC16

Originator: Presidio Pharmaceuticals Inc/Ascletis

One striking thing about this name, Ravidasvir (Ravidas+vir):

Ravidas was a North Indian Guru mystic of the bhakti movement He was active in the 15th century CE. He is often given the honorific title of Bhagat or Sant. He was a socio-religious reformer, a thinker, a theosophist, a humanist, a poet, a traveller, a pacifist and a spiritual figure. 

Hepatitis C virus infection is a major health problem worldwide and no vaccine has yet been developed against this virus. The standard therapy of pegylated-interferon and ribavirin induces serious side effects and provides viral eradication in less than 50% of patients. Combination therapy of HCV including ribavirin and interferon are currently is the approved therapy for HCV. Unfortunately, such combination therapy also produces side effects and is often poorly tolerated, resulting in major clinical challenges in a significant proportion of patients. The combination of direct acting agents can also result in drug-drug interactions. To date, no HCV therapy has been approved which is interferon free. There is therefore a need for new combination therapies which have reduced side effects, and interferon free, have a reduced emergence of resistance, reduced treatment periods and/or and enhanced cure rates.

Nonstructural protein 5A (NS5A) is a zinc-binding and proline-rich hydrophilic phosphoprotein that plays a key role in Hepatitis C virus RNA replication. 

A number of direct-acting antiviral agents (DAAs) are under development for the treatment of chronic HCV infection. These agents block viral production by directly inhibiting one of several steps of the HCV lifecycle. several viral proteins involved in the HCV lifecycle, such as the non-structural (NS)3/4A serine protease, the NS5B RNA-dependent RNA polymerase (RdRp), and the NS5A protein, have been targeted for drug development. Two NS3/4A protease inhibitors already approved for clinical use, numerous other protease inhibitors are being developed as well as inhibitors of viral replication, including nucleoside/nucleotide analogue inhibitors of HCV RdRp, non-nucleoside inhibitors of RdRp, cyclophilin inhibitors, and NS5A inhibitors. 

Inhibition of NS5A at picomolar concentrations has been associated with significant reductions in HCV RNA levels in cell culture-based models, which makes these agents among the most potent antiviral molecules yet developed.

1H NMR (Estimated) for Ravidasvir

Activity:

This NS5A inhibitor has been shown to possess high efficacy against HCV genotype 1, with up to 3.7 log₁₀ mean HCV RNA reductions, in a Phase Ib clinical trial. Activity was demonstrated against variants harbouring the L31M substitution. In an added genotype-2/3 cohort, the first 2 patients achieved mean 3.0 log₁₀ RNA level reductions [1].

Results from the Phase IIa study involving a combination therapy with Faldaprevir and Deleobuvir plus Ravidasvir came with positive news where the said combination cured 92 percent of those with genotype 1a of hepatitis C virus (HCV) when given with ribavirin.  The results presented at the 49th annual meeting of the European Association for the Study of the Liver (EASL) in London [2, 3].

The 36 study participants were randomly dived into three even cohorts of 12 each: The first received 600 mg of Deleobuvir twice a day as well as once-daily doses of Faldaprevir (120 mg), Ravidasvir and Ribavirin. The second group received the same regimen except the Faldaprevir dose was 400 mg. The third group took the regimen with the higher dose of Faldaprevir, but without Ribavirin. All participants were treated for 12 weeks with follow up for next 24 weeks.

Ninety-two percent of the first and second cohorts (11 out of 12 in both cases) achieved a sustained virologic response 12 weeks after completing therapy (SVR12, considered a cure). In the end, 14 participants were required for the third cohort, because one was incarcerated early on during treatment and another experienced viral rebound at week eight as a result of not adhering to the treatment regimen. Of the other 12 participants, eight, or two-thirds, have achieved an SVR12, while one more participant stopped taking the therapy at week eight but has since achieved an SVR8. 

References:
1. Lalezari, J. P.; et. al. PPI-668, a potent new pan-genotypic HCV NS5A inhibitor: phase 1 efficacy and safety. Hepatology 2012, 56, 1065A-1066A.
2. ClinicalTrials.gov A Study of the Efficacy and Safety of PPI-668 (NS5A Inhibitor) Plus Sofosbuvir, With or Without Ribavirin, in Patients With Chronic Hepatitis C Genotype-4. NCT02371408 (retrieved on 24-03-2015)
3. ClinicalTrials.gov Study of PPI-668, BI 207127 and Faldaprevir, With and Without Ribavirin, in the Treatment of Chronic Hepatitis C. NCT01859962 (retrieved on 15-09-2015)
4. Lalezari, J.; et. al. High rate of sustained virologic response in patients with hcv genotype-1a infection: a phase 2 trial of faldaprevir, deleobuvir and ppi-668, with and without ribavirin. EASL-The International Liver Congress 2014 - 49th Annual Meeting of the European  Association for the Study of the Liver London, United Kingdom  April 9-13 (article here)