Setback for Gilead's oral hep C drug candidate

There was disappointment for US biotech firm Gilead Sciences (Nasdaq: GILD) last Friday, when the company announced that the majority of hepatitis C genotype 1 patients with a prior null response to an interferon (IFN)-containing regimen enrolled in the ongoing ELECTRON study experienced viral relapse within four weeks of completing 12 weeks of treatment with GS-7977 plus ribavirin (RBV).

10 patients were randomized to this arm of the ELECTRON study and data are available for eight of the 10 patients at this time. Among these eight patients, six have experienced viral relapse. Two patients have not relapsed; however, they have only reached the two week post-treatment time point.

GS-7977 was acquired along with Gilead’s $11 billion purchase of Pharmasset, which completed last month and was aimed at expanding the company’s hepatitis C franchise (The Pharma Letter November 22). The deal included PSI-7977, which is also being investigated in combination with Bristol-Myers Squibb’s BMS-790052 in the treatment of chronic HCV, and these add to Gilead’s own portfolio of seven HCV candidates.