Photo by Bill Branson
Vials of drug
The US Food and Drug Administration (FDA) has approved inotuzumab ozogamicin (Besponsa®) for the treatment of adults with relapsed or refractory B-cell precursor acute lymphoblastic leukemia (ALL).
The labeling for inotuzumab ozogamicin includes a boxed warning stating that the drug poses a risk of hepatotoxicity, including hepatic veno-occlusive disease (or sinusoidal obstruction syndrome), as well as an increased risk of post-transplant non-relapse mortality.
The full prescribing information for inotuzumab ozogamicin is available at https://www.accessdata.fda.gov/drugsatfda_docs/label/2017/761040s000lbl.pdf.
Inotuzumab ozogamicin is an antibody-drug conjugate that consists of a monoclonal antibody targeting CD22 and a cytotoxic agent known as calicheamicin.
The product originates from a collaboration between Pfizer and Celltech (now UCB), but Pfizer has sole responsibility for all manufacturing and clinical development activities.
Inotuzumab ozogamicin was reviewed and approved under the FDA’s breakthrough therapy designation and priority review programs.
The application for inotuzumab ozogamicin was supported by results from the phase 3 INO-VATE trial, which were published in NEJM in June 2016.
The trial enrolled 326 adults with relapsed or refractory B-cell ALL. Patients received inotuzumab ozogamicin or 1 of 3 chemotherapy regimens (high-dose cytarabine, cytarabine plus mitoxantrone, or fludarabine, cytarabine, and granulocyte colony-stimulating factor).
The rate of complete remission, including incomplete hematologic recovery, was 80.7% in the inotuzumab arm and 29.4% in the chemotherapy arm (P<0.001). The median duration of remission was 4.6 months and 3.1 months, respectively (P=0.03).
Forty-one percent of patients treated with inotuzumab and 11% of those who received chemotherapy proceeded to stem cell transplant directly after treatment (P<0.001).
The median progression-free survival was 5.0 months in the inotuzumab arm and 1.8 months in the chemotherapy arm (P<0.001).
The median overall survival was 7.7 months and 6.7 months, respectively (P=0.04). This did not meet the prespecified boundary of significance (P=0.0208).
Liver-related adverse events were more common in the inotuzumab arm than the chemotherapy arm. The most frequent of these were increased aspartate aminotransferase level (20% vs 10%), hyperbilirubinemia (15% vs 10%), and increased alanine aminotransferase level (14% vs 11%).
Veno-occlusive liver disease occurred in 11% of patients in the inotuzumab arm and 1% in the chemotherapy arm.
There were 17 deaths during treatment in the inotuzumab arm and 11 in the chemotherapy arm. Four deaths were considered related to inotuzumab, and 2 were thought to be related to chemotherapy.
