Idenix and Novartis AG --with whom Idenix is collaborating on the development of valopicitabine as a treatment for hepatitis C -- lowered the daily dosages given in its Phase IIb trials of the drug to 200 milligrams or 400 milligrams, from the original 800 milligram dosage. The Food and Drug Administration has agreed to the change in the ongoing trials, Idenix said.