The discovery and optimization of naphthalene-linked P2-P4 Macrocycles as inhibitors of HCV NS3 protease.

Naphthalene-linked P2-P4 macrocycles within a tri-peptide-based acyl sulfonamide chemotype have been synthesized and found to inhibit HCV NS3 proteases representing genotypes 1a and 1b with single digit nanomolar potency. The pharmacokinetic profile of compounds in this series was optimized through structural modifications along the macrocycle tether as well as the P1 subsite. Ultimately a compound with oral bioavailability of 100% in rat, and a long half-life in plasma was obtained. However, compounds in this macrocyclic series exhibited cardiac effects in an isolated rabbit heart model and for this reason further optimization efforts were discontinued.

Discovery and early clinical evaluation of BMS-605339, a potent and orally efficacious tripeptidic acylsulfonamide NS3 protease inhibitor for the treatment of hepatitis C virus infection.

The discovery of BMS-605339 (35), a tripeptidic inhibitor of the NS3/4A enzyme, is described. This compound incorporates a cyclopropylacylsulfonamide moiety that was designed to improve the potency of carboxylic acid prototypes through the introduction of favorable nonbonding interactions within the S1' site of the protease. The identification of 35 was enabled through the optimization and balance of critical properties including potency and pharmacokinetics (PK). This was achieved through modulation of the P2* subsite of the inhibitor which identified the isoquinoline ring system as a key template for improving PK properties with further optimization achieved through functionalization. A methoxy moiety at the C6 position of this isoquinoline ring system proved to be optimal with respect to potency and PK, thus providing the clinical compound 35 which demonstrated antiviral activity in HCV-infected patients.

Virological escape in HCV genotype-1-infected patients receiving daclatasvir plus ribavirin and peginterferon alfa-2a or alfa-2b.

BACKGROUND: Daclatasvir (DCV; BMS-790052) is a picomolar inhibitor of HCV non-structural protein 5A (NS5A) and has demonstrated efficacy in patients chronically infected with HCV. METHODS: In the double-blind, randomized studies AI444021 and AI444022, 71 Japanese patients chronically infected with HCV genotype 1 (predominantly genotype 1b) received DCV (10 mg or 60 mg) plus peginterferon alfa-2b or alfa-2a and ribavirin. Virological failure occurred in 14% (5/36) of treatment-naive patients and 54% (19/35) of prior alfa/ribavirin non-responders. Resistance testing was performed on baseline samples and samples with HCV RNA≥1,000 IU/ml at week 1 through post-treatment week 24. RESULTS: Baseline NS5A resistance-associated polymorphisms had less impact on virological response rates than IL28B genotype. All patients with virological failure had NS5A DCV-resistant variants at the time of failure. The predominant NS5A variants were L31V/M/I plus Y93H; this combination was detected in 100% (5/5) of treatment-naive patients and 74% (14/19) of non-responders with failure. Emergent resistance variants in prior non-responders (four viral breakthroughs, one relapse) were more varied with novel combinations such as L31F-ΔP32 and L28M-R30Q-A92K detected. Significant loss in DCV antiviral activity was generally only seen with ≥ two resistance-associated NS5A substitutions. All DCV-resistant variants were still detected at end of study. CONCLUSIONS: Virological failure in HCV genotype 1b treatment-naive Japanese patients receiving DCV plus alfa-2a/ribavirin or alfa-2b/ribavirin was associated with enrichment of NS5A resistance variants L31V/M-Y93H. In prior non-responders, emergent variants associated with failure also included NS5A-A92K or NS5A-ΔP32. As with L31-Y93 variants, these variants persisted.