Tanox announced late yesterday that the FDA has asked for another dosing trial of its experimental HIV/AIDS drug TNX-355 before it can make a decision on the therapy. Talks are planned over the next few weeks to clarify what the FDA is looking for, says Tanox, and may delay its planned application for approval. Tanox officials did indicate, though, that the FDA said a successful trial could serve as a pivotal study necessary for approval. Release