In this article, we will discuss BESPONSA (Mechanism of Action). So, let’s get started.
Mechanism of Action
Inotuzumab ozogamicin is a CD22-directed antibody-drug conjugate (ADC). Inotuzumab recognizes human CD22. The small molecule, N-acetyl-gamma-calicheamicin, is a cytotoxic agent that is covalently attached to the antibody via a linker. Nonclinical data suggest that the anticancer activity of inotuzumab ozogamicin is due to the binding of the ADC to CD22-expressing tumor cells, followed by internalization of the ADC-CD22 complex, and the intracellular release of N-acetyl-gamma-calicheamicin
dimethylhydrazide via hydrolytic cleavage of the linker. Activation of N-acetyl-gamma-calicheamicin dimethylhydrazide induces double-strand DNA breaks, subsequently inducing cell cycle arrest and apoptotic cell death.
During the treatment period, the pharmacodynamic response to BESPONSA was characterized by the depletion of CD22-positive leukemic blasts.
In a randomized clinical study in patients with relapsed or refractory ALL, increases in QTcF of ≥ 60 msec from baseline were measured in 4/162 patients (3%) in the BESPONSA arm and 3/124 patients (2%) in the Investigator’s choice of chemotherapy arm. Increases in QTcF of > 500 msec were observed in none of the patients in the BESPONSA arm and 1/124 patients (1%) in the Investigator’s choice of
chemotherapy arm. Central tendency analysis of the QTcF interval changes from baseline showed that the highest mean (upper bound of the 2-sided 90% CI) for QTcF was 15.3 (21.1) msec, which was observed at Cycle 4/Day 1/1 hour in the BESPONSA arm.