Besponsa (inotuzumab ozogamicin), indicated for the treatment of adults with relapsed or refractory B-cell precursor acute lymphoblastic leukemia, was granted approval from the US Food and Drug Administration (FDA) under its breakthrough therapy designation and priority review programme.. Gemtuzumab ozogamicin is a drug-linked monoclonal antibody that was used to treat acute myeloid leukemia from 2000 to 2010. It was withdrawn from market in June 2010 when a clinical trial showed the drug increased patient death and added no benefit over conventional cancer therapies. It was re-introduced into the US market in 2017.. Pfizer’s Mylotarg and Besponsa join only Genentech’s Kadcyla (ado-trastuzumab emtansine) and Takeda/Seattle Genetics’ Adcetris (brentuximab vedotin).. Besponsa . inotuzumab ozogamicin . On 21 April 2017, the Committee for Medicinal Products for Human Use (CHMP) adopted a positive opinion, recommending the granting of a . marketing authorisation for the medicinal product Besponsa, intended for the treatment of adults with acu te lymphoblastic leukaemia . Besponsa was designated as an orphan medicinal product on 7 June 2013. The applicant for . Gemtuzumab ozogamicin (Mylotarg®; Pfizer/Wyeth-Ayerst Laboratories) is a recombinant, humanized anti-CD33 monoclonal antibody (IgG4 κ antibody hP67.6) covalently attached to the cytotoxic antitumor antibiotic calicheamicin (N-acetyl-γ-calicheamicin) via a bifunctional linker (4-(4-acetylphenoxy. MYLOTARG (gemtuzumab ozogamicin) is a prescription medicine used to treat adults with newly diagnosed CD33-positive acute myeloid leukemia (AML) or patients over the age of 2 with CD33-positive AML whose disease returned or did not respond to previous treatment..