CAMBRIDGE, Mass.--(BUSINESS WIRE)--Genzyme Corporation (Nasdaq: GENZ) announced today that the FDA provided a complete response letter regarding the company’s supplemental New Drug Application for Clolar® (clofarabine) in previously untreated older adult patients with acute myeloid leukemia (AML) and at least one unfavorable baseline prognostic factor. The agency recommended a randomized, controlled clinical study be conducted for label expansion of Clolar in this indication.