Subcutaneous Blinatumomab Achieves 77% CR in Relapsed/Refractory B-ALL, Surpassing IV Benchmarks

Blinatumomab, a CD19×CD3 bispecific T-cell engager, was reformulated for subcutaneous (SC) delivery and evaluated in the phase 1/2 NCT04521231 study across 88 adults with relapsed/refractory B-cell ALL. Once-daily 250 µg (week 1) then 500 µg thrice-weekly, or 500 µg→1000 µg schedules produced complete remission/CRh in 75% and 79% of patients, respectively (overall 77%), after a median 5-month follow-up. Grade 3-4 toxicities were neutropenia 22%, cytokine-release syndrome 20%, and ICANS 17%; no treatment-related deaths occurred. By comparison, intravenous blinatumomab in the TOWER trial achieved 44% CR/CRh and median OS 7.7 months, while salvage chemotherapy historically yields 18-44% remissions, underscoring the SC regimen’s higher early response without continuous infusion pumps