Besponsa and Blincyto Combination Expanded in Phase 2 for CD22-Positive B-ALL
Clinical Design and Patient Population
The NCT03739814 trial, supported by the National Cancer Institute and led by the Alliance for Clinical Trials in Oncology, is an active, multi-center Phase 2 trial with a target enrollment of 84 patients. The study evaluates one-year event-free survival and tolerability in newly diagnosed elderly and transplant-ineligible patients, as well as relapsed/refractory CD22-positive B-cell acute lymphoblastic leukemia (B-ALL) patients. In the Philadelphia chromosome-negative cohort, Inotuzumab ozogamicin is followed by Blinatumomab, while the positive cohort receives Ponatinib to test treatment intensity tailored to biological subtypes.
Complementary Targeting Strategy
Pfizer (PFE)'s approved drug Besponsa (Inotuzumab ozogamicin) is an antibody-drug conjugate (ADC) combining a CD22 antibody with calicheamicin, tasked with reducing tumor burden. Amgen (AMGN)'s approved drug Blincyto (Blinatumomab) is a bispecific T-cell engager (BiTE) connecting CD19 and T-cell CD3, targeting residual leukemia. The sequential targeting of different antigens aims to reduce antigen loss and resistance issues that may arise after single CD19 or CD22 therapy, while deepening minimal residual disease (MRD)-negative remission.
Triple Mechanism in Ph-Positive Cohort
Takeda Pharmaceutical (TAK)'s approved drug Iclusig (Ponatinib) is a tyrosine kinase inhibitor (TKI) suppressing BCR::ABL1 and T315I mutations. Cohort 3 blocks proliferation signals with Ponatinib while sequentially combining Besponsa and Blincyto, and applies up to 24 months of Ponatinib maintenance in remission patients. This strategy validates a remission induction and consolidation approach with reduced dependency on cytotoxic chemotherapy for Ph-positive elderly or high-intensity Hyper-CVAD-ineligible patients.
Regulatory and Competitive Landscape
The FDA initially approved Blincyto on December 3, 2014, and expanded its indication for Ph-negative B-ALL on June 14, 2024. Besponsa was approved for adult relapsed/refractory B-ALL on August 17, 2017, and for CD22-positive patients aged one year and older on March 6, 2024. Iclusig and chemotherapy received accelerated approval for newly diagnosed adult Ph-positive ALL on March 19, 2024. Competitive treatments include allogeneic hematopoietic stem cell transplantation and CD19 CAR-T therapies such as Novartis' Kymriah, Gilead's Tecartus, and Autolus Therapeutics' Obe-cel series. Considering the estimated 2025 global B-cell ALL treatment market revenue of $3.46825 billion, this combination could become an immediately available alternative between existing monotherapy immunotherapies and high-cost CAR-T if it proves survival and safety benefits.
In the short term, the Phase 2 trial with a target of 84 patients focuses on one-year event-free survival and the balance between hepatic veno-occlusive disease, neurotoxicity, and cytokine release syndrome, rather than changing standard-of-care. In the medium to long term, if the sequential combination of CD22 ADC and CD19/CD3 BiTE proves effective, it will support Pfizer (PFE) and Amgen (AMGN)'s lifecycle extension of their marketed assets and a strategy to reduce chemotherapy use. The triple mechanism in the Ph-positive cohort provides a rationale for Takeda Pharmaceutical (TAK)'s Iclusig to expand into combination regimens based on immunotherapy after its 2024 accelerated approval for newly diagnosed indications. For researchers, it offers an opportunity to validate whether MRD-negative remission and CD19/CD22 antigen changes function as predictive biomarkers for resistance. In the 2025 B-cell ALL market estimated at $3.46825 billion, the efficacy, safety, and dosing convenience comparison with CD19 CAR-T therapies like Kymriah and Tecartus, as well as allogeneic transplantation, will determine the extent of market penetration.
Source: ClinicalTrials.gov (api_ct)