Idenix lowers NM283 dosage after AE reports

Idenix Pharmaceuticals, a US biopharmaceutical company focused on viral and other infectious diseases, has modified its ongoing Phase IIb hepatitis C trials of its drug candidate valopicitabine (NM283) due to side effects.

Dosing levels for the investigational antiviral, which is being co-developed by Swiss drug major Novartis, have been reduced from 800mg/day to 200mg/day or 400mg/day as a result of dose-related gastrointestinal adverse events observed in both treatment-naive and treatment-refractory patients on 800mg regimens. The firm noted that its changes have been discussed and agreed with the US Food and Drug Administration.

Idenix stressed that the move was not a major setback to its plans. Chief executive Jean-Pierre Sommadossi noted that, "while these modifications will delay the valopicitabine development program, the primary purpose of Phase II studies is to identify the optimal dosing regimen with respect to efficacy and safety. Meaningful data from these ongoing trials, along with data from the planned ribavirin interaction study and potential additional dose-ranging data, which is expected to be available over the next six months, will provide us with necessary safety and efficacy data to further define valopicitabine's Phase III development plan."