The FDA has approved Clolar, a drug that will be used to treat childhood leukemia. The drug is being manufactured by the Genzyme Corp.

Clolar was approved as part of a treatment program for patients between the ages of one and 21 who suffer from acute lymphocytic leukemia and who have undergone a minimum of two rounds of cancer treatment. However, the drug has not been approved in the treatment of acute myeloid leukemia.

Bioenvision Inc. developed the drug but sold North American rights to Ilex Oncology Inc, which was later acquired by Genzyme. The drug is listed as a purine nucleoside analogs.

As a result of this announcement, shares of Genzyme stock increase 2% before trading began this morning.