U.S. Hepatitis Trial Put on Hold
Potential liver problems cited (July 25)
The FDA has placed a partial clinical hold on an ongoing phase II U.S. study of VX-135, a nucleotide analogue hepatitis C virus (HCV) polymerase inhibitor, because of possible liver problems.
The partial hold follows the observation of reversible elevated liver enzymes in patients receiving 400 mg of VX-135 in combination with ribavirin in a phase II study in Europe.
The hold prevents evaluation of a 200-mg dose of VX-135 in the U.S. study. Evaluation of a 100-mg dose of VX-135 in combination with ribavirin as part of the 12-week phase II study in the U.S. is continuing as planned.
The compound’s developer (Vertex Pharmaceuticals) currently markets the leading hepatitis C drug, Incivek (telaprevir). To provide high cure rates, however, that treatment must be taken with injected interferon, which is difficult to tolerate.