B-cell precursor ALL
The US Food and Drug Administration (FDA) has granted priority review for inotuzumab ozogamicin as a treatment for adults with relapsed or refractory B-cell precursor acute lymphoblastic leukemia (ALL).
The FDA grants priority review to applications for products that may provide significant improvements in the treatment, diagnosis, or prevention of serious conditions.
The agency’s goal is to take action on a priority review application within 6 months of receiving it, rather than the standard 10-month period.
The Prescription Drug User Fee Act goal date for inotuzumab ozogamicin is August 2017.
About inotuzumab ozogamicin
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.
The application for inotuzumab ozogamicin is supported by results from a phase 3 trial, which were published in NEJM in June 2016.
The trial enrolled 326 adult patients with relapsed or refractory B-cell ALL and compared inotuzumab ozogamicin to standard of care chemotherapy.
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.
