The Food and Drug Administration (FDA) has granted approval for inotuzumab ozogamicin (Besponsa, Pfizer) for pediatric patients aged 1 year and older with relapsed or refractory CD22-positive B-cell precursor acute lymphoblastic leukemia (ALL). This approval marks a significant advancement in the treatment landscape for this challenging condition.
Inotuzumab ozogamicin functions by targeting CD22-positive B-cell precursor ALL, offering a targeted therapeutic approach with potentially enhanced efficacy and reduced toxicity compared to traditional treatments. The FDA’s priority review and orphan drug designation underscore the urgency and significance of this therapy.
Image credit: Vinoth Khandelwal
Inotuzumab ozogamicin demonstrated efficacy in a multicenter, single-arm, open-label study involving 53 pediatric patients aged 1 year and older with relapsed or refractory CD22-positive B-cell precursor ALL. The study evaluated two dose levels: 1.4 mg/m2/cycle and 1.8 mg/m2/cycle. Patients typically received a median of 2 cycles of therapy, with premedications including methylprednisolone, antipyretics, and antihistamines.
The primary efficacy outcomes included complete remission (CR), duration of CR, and the proportion of patients achieving minimal residual disease (MRD) negative CR. CR was defined by < 5% blasts in the bone marrow, absence of peripheral blood leukemia blasts, full recovery of peripheral blood counts, and resolution of any extramedullary disease. MRD negativity was assessed by flow cytometry or PCR. Among all patients, 42% achieved CR, with a median duration of CR of 8.2 months. Notably, the MRD negativity rate in patients with CR was high, indicating a substantial reduction in residual disease burden. The most common adverse reactions, including laboratory abnormalities, included thrombocytopenia, pyrexia, anemia, vomiting, infection, hemorrhage, neutropenia, nausea, leukopenia, febrile neutropenia, increased transaminases, abdominal pain, and headache.
Inotuzumab ozogamicin’s approval offers new hope for pediatric patients battling relapsed or refractory CD22-positive B-cell precursor ALL. This approval represents a significant milestone in the ongoing fight against pediatric ALL, underscoring the importance of continued research and innovation in pediatric oncology.
