Pharmasset's QUANTUM study was supposed help find an effective oral regimen to treat GT1 HCV by using combinations of PSI-938, PSI-7977 and ribavirin. It's going to take a lot of firepower to cure GT1 HCV with an oral regimen and now they are left with just PSI-7977/ribavirin to do the job. Based on everything I have read (especially the misleading pangenotypic, interferon intolerant study designs) coming out of Pharmasset, they are destined to fail with their PSI-7977/ribavirin in GT1 HCV. And now, with the failure of PSI-938, they have no back up plan.
PSI-7977 is now the only silver bullet if that were the problem then VRUS stock would have tanked more than $4. We'll see what happens when and if it becomes a toxic bullet for GILD. I'm still long VRTX and I have been for the last 8+ years.
This is my opinion--that Pharmasset will fail to have a significant oral cure rate for GT1 HCV. If Pharmasset knew they could cure GT1 HCV with PSI-7977/ribavirin, they would be doing a study with PSI-7977/ribavirin on GT1 HCV patients regardless of their tolerance/intolerance of interferon. Instead, the NEUTRINO study will include only "interferon intolerant" patients without regard to genotype.