FDA approves Pfizer’s Besponsa (inotuzumab ozogamicin) for Pediatric CD22+ B-Cell Precursor Acute Lymphoblastic Leukemia (B-ALL)

On Mar. 6, 2024, US FDA approved Pfizer’s Besponsa (inotuzumab ozogamicin) for pediatric patients 1 year and older with r/r CD22+ B-ALL.

Besponsa was initially approved in August 2017 for adult patients.

This application was granted:

·         Priority Review

·         Orphan Drug Designation

Efficacy was established based on the Complete Remission (CR) rate, duration of CR, and proportion of patients with minimal residual disease (MRD) negative CR assessed by flow cytometry or PCR.

In all patients, 22/53 (42%, 95% CI 28.1-55.9%) patients achieved CR, and the median duration of CR was 8.2 months (95% CI: 2.6-NE).

MRD negativity rate in patients with CR was 21/22 [95.5% (95% CI: 77.2, 99.9)] based on flow cytometry, and 19/22 [86.4% (95% CI: 65.1, 97.1] based on RQ-PCR.

The most common adverse reactions (≥20%), including laboratory abnormalities, were thrombocytopenia, pyrexia, anemia, vomiting, infection, hemorrhage, neutropenia, nausea, leukopenia, febrile neutropenia, increased transaminases, abdominal pain, and headache.

WI203581 (ITCC-059; Eudra CT Number: 2016-000227-71) is an European Phase 1/2, multicenter, open-label study. Efficacy was evaluated in 53 pediatric patients. 

Two dose levels were evaluated--an initial dose of 1.4 mg/m2/cycle in 12 patients and 1.8 mg/m2/cycle in 41 patients.

Link to FDA approval announcement

Link to product label

Link to Ph 1 Study Publication Blood 2021

Link to previous FDA approval announcement 2017