Gilead Sciences, Inc. ( GILD ) recently received encouraging news when the Data and Safety Monitoring Board (DSMB) recommended the continuation of the enrollment process of the company's phase III study (ION-1) following a planned review of the safety data from the study.
The study is evaluating a fixed-dose combination of Gilead's candidate sofosbuvir (formerly GS-7977) and ledipasvir (formerly GS-5885) with and without ribavirin (RBV) in treatment-naïve patients infected with the genotype 1 version of hepatitis C virus (HCV) infection.
The DSMB gave its recommendation following its review of the safety data from 200 patients in all four arms of the ION-1 study in addition to SVR4 rates (sustained virologic response 28 days post treatment) from 100 HCV patients in the two cohorts of 12-week duration. Following the positive development, Gilead has started enrolling the remaining 600 patients in the study.
Apart from ION-1, Gilead is also evaluating the combination of sofosbuvir and ledipasvir in 400 treatment-experienced patients infected with the genotype 1 version of HCV in another phase III study (ION-2). The company is evaluating the above combination with RBV for 12 weeks and with and without RBV for 24 weeks. The patients who are being evaluated in the study did not respond to treatment by a regimen containing pegylated interferon (peg-IFN) or peg-IFN and a protease inhibitor.
We note that apart from ION-1 and ION-2, Gilead is evaluating sofosbuvir in HCV patients in other phase III studies also. Gilead intends to seek regulatory approvals for the candidate in the US and EU, based on data from these studies, in the second quarter of 2013.
Successful development of sofosbuvir would not only boost Gilead's top line, but also strengthen its position in the lucrative HCV market. A sizeable population suffers from HCV the world over.