Antibody-Targeted Chemotherapy in Relapsed AML

SEATTLE—Preliminary phase II data show that CMA-676, an engineered human anti-CD33 antibody linked to calicheamicin, a potent cytotoxic agent, produced an objective response in 10 of 23 patients (43%) with acute myelogenous leukemia in first relapse after initial chemotherapy. Six responders went on to allogeneic bone marrow transplant.

“The side effects are mild compared to standard chemotherapy,” Eric Sievers, MD, of Fred Hutchinson Cancer Research Center, said at ASH. The antibody was given as a single agent intravenously at a dose of 9 mg/m² every 2 weeks for two doses. The agent, from Wyeth-Ayerst Research (Radnor, PA), is being tested at 13 leading US leukemia centers.