FDA confirms no drugs equivalent to BiDil

US firm NitroMed says that the Food and Drug Administration issued a letter on May 4 confirming that it has not approved any drug that is therapeutically equivalent or substitutable to BiDil, the firm's fixed-dose combination of isosorbide dinitrate/hydralazine HCl, approved as adjunct treatment of heart failure in self-identified black patients. Moreover, the FDA confirmed that neither approved labeling for isosorbide dinitrate nor approved labeling for hydralazine HCl contains information regarding the use of these drug products for the treatment of heart failure. The statements contained in the letter are consistent with the FDA's Orange Book and the agency-approved labeling for BiDil and confirm that the FDA does not consider other drug products to be substitutable for BiDil.

The letter written by the FDA was initiated by a Citizen Petition from NitroMed for confirmation on the substitution status for BiDil. NitroMed sought confirmation in an effort to address anecdotal reports that information is being disseminated regarding the availability of substitutable or generic versions of its drug.