GS-4104 Gilead Sciences Inc.

Abstract Gilead and Roche are codeveloping GS-4104, a neuraminidase inhibitor, for the potential treatment and prevention of influenza virus infections, type A and type B. The companies began international phase II/III trials in December 1997 [272638]. The phase II/III double-blind, placebo-controlled study involves centers in the US, Canada, Europe and Hong Kong [272638]. The program will consist of two treatment studies and two prophylaxis studies, each of which will recruit 750 patients [273331]. The trials involve over 1500 patients, who will receive either GS-4104 or placebo for 6 weeks, as a once- or twice-daily dosing schedule [276650], [276895]. The company has also registered 73 centers for the two treatment studies, and 55 of these had been activated by the end of January 1998. Patients in the treatment arm will receive either GS-4104 or placebo for 5 days. Roche is conducting similar trials in Europe, Canada and Hong Kong [276895]. In September 1997, results were announced from two phase II studies, initiated in May 1997, in which volunteers were exposed intranasally to influenza A. The patients received oral capsules of GS-4104, or placebo, once-daily or twice-daily. In the first study, GS-4104 decreased the duration of symptoms by nearly 50%. In the second study, all patients who were given GS-4104 prophylactically did not have detectable levels of virus, as compared to 50% in the placebo group [264362]. In phase I trials, GS-4104 was well-tolerated with good oral absorption and distribution in blood and tissue [248180].