CD33 and acute myeloid leukemia: The negative results from those studies (NCT00085709;ISRCTN17161961) prompted Pfizer to withdraw gemtuzumab ozogamicinfrom the market in 2010.461−463 Later on, based on the positiveresults of subsequent trials (NCT00927498; NCT00091234), using reduceddosing strategies, gemtuzumab ozogamicin was reapproved by the USFDAin 2017 for treatment of newly diagnosed CD33-positive AML as wellas for relapsed or refractory CD33-positive AML.127,463,464