The safety and efficacy of Besponsa were studied in a randomized trial of 326 patients with relapsed or refractory B-cell ALL who had received one or two prior treatments. Patients were randomized to receive treatment with Besponsa or an alternative chemotherapy regimen. The trial measured the percentage of patients with no evidence of disease and full recovery of blood counts after treatment (complete remission or CR). Of the 218 evaluated patients, 35.8 percent who received Besponsa experienced CR for a median 8.0 months; of the patients who received alternative chemotherapy, 17.4 percent experienced CR for a median 4.9 months.. The U.S. Food and Drug Administration today approved Besponsa (inotuzumab ozogamicin) for the treatment of adults with relapsed or refractory B-cell precursor acute lymphoblastic leukemia (ALL).. Pfizer Inc. (NYSE:PFE) today announced that the European Commission has approved BESPONSA® (inotuzumab ozogamicin) as monotherapy for the treatment of adults with relapsed or refractory CD22-positive B-cell precursor acute lymphoblastic leukemia (ALL)..