Replies to post #116150 on Biotech Values

[DewDiligence]

VRUS’ 2-drug oral combo consisting of PSI-7977+PSI-938 looks like a better bet than VRTX’s 2-drug oral combo of Telaprevir+VX-222, but I think a cocktail of three oral drugs will likely be needed to generate the kind of SVR rate capable of supplanting the current SoC of interferon and ribavirin.

I’m surprised that VRTX is sticking so strongly with VX-222; by all accounts, VX-222 appears to be falling short of the expectations VRTX had when it acquired the drug in the ViroChem deal two years ago (#msg-36022943).

[Preciouslife1]

Thomas, thanx for adding to the post ... appreciated .. Mark

http://www.pharmasset.com/pipeline/psi_938_psi_879.aspx

PSI-938 / PSI-661
PSI-938 and PSI-661 are guanine nucleotide analog polymerase inhibitors for the treatment of chronic HCV infection. The drug candidates use different prodrug strategies, but are metabolized to the same active purine triphosphate in human hepatocytes.

PSI-938PSI-938 has demonstrated in vitro anti-HCV activity with EC90 values of 1.43 +/- 0.67 µM. PSI-938 has demonstrated equivalent potency against the S282T mutant which has reduced sensitivity to several other nucleoside analogs including RG7128, PSI-7977, NM283, and IDX184, and is metabolized to the active triphosphate form through a different phosphorylation pathway than our pyrimidine product candidates, RG7128 and PSI-7977, supporting a scientific rationale for a low likelihood of antagonism with the combination. The in vitro half-life of the triphosphate in primary human hepatocytes is approximately 12 hours, which supports the exploration of once-daily dosing in early development.

NUCLEAR StudyIn December 2010, Pharmasset initiated Part 2 of a Phase 1 study that includes the first combinations of a purine (PSI-938) and a pyrimidine (PSI-7977) nucleotide analog for the treatment of HCV. The cohorts within Part 2 are expected to evaluate PSI-938 QD as monotherapy and in combination with PSI-7977 QD. The primary objective of Part 2 of this study is to assess the safety, tolerability and pharmacokinetics of PSI-938 alone and in combination with PSI-7977 in individuals with HCV GT1 for 14 days. The secondary objective of Part 2 of this study is to evaluate the short-term change in HCV RNA. Forty patients with HCV genotype 1 are expected to be randomized into one of four cohorts (10 patients per cohort, n = 8 and placebo = 2)

The link provided contains the rest of the information..




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