The US Food and Drug Administration (FDA) granted approval to inotuzumab ozogamicin (Besponsa) for the treatment of adults with relapsed/refractory (R/R) B-cell precursor acute lymphoblastic leukemia (ALL).1,2

Inotuzumab ozogamicin is an antibody-drug conjugate comprised of a monoclonal antibody that targets CD22 — a cell surface antigen that is expressed on almost all B-cell ALL cancer cells — linked to the cytotoxic agent calicheamicin.

The FDA based its approval on evidence from the phase 3 INO-VATE trial ( Identifier: NCT01564784), in which researchers evaluated the safety and efficacy of inotuzumab ozogamicin compared with investigators’ choice (IC) medication in 326 patients.

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Patients who received inotuzumab ozogamicin achieved a significantly higher complete remission (CR) rate (80.7%; 95% CI, 72.1-87.7) than did patients receiving the IC medication (29.4%; 95% CI, 21.0-38.8; P <.001).  Of the patients who achieved CR, 35.8% in the inotuzumab ozogamicin arm maintained CR for a median of 8.0 months, and 17.4% in the IC arm maintained CR for a median of 4.9 months.

Median overall survival was longer in the inotuzumab ozogamicin arm (7.7 months [95% CI, 6.0-9.2]) vs the IC arm (6.2 months [95% CI, 4.7-8.3]). But this finding was not considered significant.

Frequently reported adverse events included thrombocytopenia, neutropenia, leukopenia, infection, anemia, hemorrhage, fatigue, fever, nausea, headache, liver damage, hyperbilirubinemia, and abdominal pain.

Inotuzumab ozogamicin previously received Orphan Drug designation.


  1. FDA approves new treatment for adults with relapsed or refractory acute lymphoblastic leukemia [news release]. Silver Spring, MD: US Food and Drug Administration; August 17, 2017. Accessed August 17, 2017.
  2. Kantarjian HM, DeAngelo DJ, Stelljes M, et al. Inotuzumab ozogamicin versus standard therapy for acute lymphoblastic leukemia. N Eng J Med. 2016:375(8);740-753.