Mortality concerns that led to the halting of a Phase III blood substitute trial by Baxter Healthcare Corp. in March now may be prompting the FDA to push blood substitute companies to collect more robust safety data. The agency has asked Northfield Laboratories Inc. (NFLD) to expand an ongoing Phase III trial of its PolyHeme hemoglobin-based product from 240 patients to 600, and it appears that other companies are being asked to do the same.

While the FDA doesn't comment on ongoing studies, NFLD said the agency expressed concerns based on safety issues raised in other trials. NFLD Chairman and CEO Richard DeWoskin suggested the HemAssist data were likely the basis of the FDA's concern. DeWoskin said the agency told him the request to enlarge trials will be across the board to blood substitute manufacturers. He did not know whether the agency is limiting its concerns to hemoglobin-based products.