The FDA approved Pfizer’s Mylotarg (gemtuzumab ozogamicin) for newly diagnosed acute myeloid leukemia expressing the CD33 antigen. The agency also approved Mylotarg for the treatment of patients age 2 and older with CD33-positive AML who have experienced a relapse or not responded to initial treatment.
After receiving accelerated approval in 2000, Pfizer withdrew Mylotarg from the market in 2010, after trials failed to verify clinical benefit and demonstrated safety concerns, including deaths. The new approval includes a lower dose and different schedule, both in combination with chemotherapy and alone, as well as a new patient population.
Safety and efficacy were studied in 271 patients who were randomized to receive Mylotarg in combination with daunorubicin and cytarabine chemotherapy versus daunorubicin and cytarabine alone. Patients who received Mylotarg went longer without complications: 17.3 months, compared to 9.5 months with chemotherapy alone. Two clinical trials evaluated Mylotarg as a stand-alone treatment, demonstrating improvements in medial overall survival.