Recent research and future prospects for gemtuzumab ozogamicin: could it make a comeback?

Gemtuzumab ozogamicin (GO), a humanized anti-CD33 monoclonal antibody conjugated to calicheamicin, was initially granted accelerated US FDA approval for the treatment of acute myeloid leukemia (AML), but was later voluntarily withdrawn from the market because of increased toxicity and lack of benefit in a Phase III clinical trial. However, subsequently published clinical trials that compared standard chemotherapy to chemotherapy plus GO in children and adults with AML demonstrated clinical benefit of GO in certain subgroups of patients, leading to renewed interest in GO. Although the re-emergence of GO into the clinic is uncertain, these results validate the use of CD33 as a target for AML therapy. Much research is underway to develop novel anti-CD33 therapeutics that may be able to pick up where GO left off.