AHP gains Mylotarg approval in USA, first launch shortly

American Home Products has won US Food and Drug Administration approvalto market its anticancer agent Mylotarg (gemtuzumab ozogamicin for injection) for use in CD33-positive acute myeloid leukemia; the first antibody-targeted chemotherapy, claims the firm. Shares in the company rose 2.2% on the day of the announcement (May 18) to close at $58.00 on a volume of more than 2.5 million shares traded. While this is a boost to the firm, which has sunk to a year-low of $36.50, it is still some way off its year high of $152.25.

The specific approval was for the treatment of patients aged over 60 years with AML who are in first relapse and are not considered candidates for cytotoxic chemotherapy. While this may be seen as a limited patient population, the majority of the 10,000 AML patients in the USA are over the age of 60 and there are currently no available medications for the treatment of relapsed AML.

However, the approval was not easily-won. While the FDA's advisory committee earlier this year recommended by a vote of 11-2 that Mylotarg had "acceptable" efficacy, the panel had initially voted that AHP's Wyeth-Ayerst division (which will market the drug) had not proven that Mylotarg had comparable efficacy to other salvage therapies in treating relapsed AML (Marketletter March 27).