Addition of Blinatumomab to Standard Chemotherapy in B-Cell ALL in Low-Risk First Relapse

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As reported in the Journal of Clinical Oncology by Hogan et al, the phase III Children’s Oncology Group AALL1331 trial has shown that the addition of blinatumomab to standard chemotherapy improved survival outcomes among younger patients with low-risk B-cell acute lymphoblastic leukemia (ALL) in first relapse, whether the relapse occurred in the bone marrow alone or was also an extramedullary recurrence.

Study Details

The trial included 255 patients with low-risk relapse aged 1 to 30 years enrolled between January 2014 and September 2019. After reinduction, patients were randomly assigned to two blocks of continuation chemotherapy/maintenance with (n = 127) or without (n = 128) interspersed blocks of blinatumomab. The primary and secondary endpoints were disease-free survival and overall survival.

Key Findings

Among all patients, there were no significant differences in 4-year disease-free survival in the blinatumomab group (61.2% ± 5.0%) vs the chemotherapy group (49.5% ± 5.2%; P = .089) or in 4-year overall survival (90.4% ± 3.0% vs 79.6% ± 4.3%, P = .11).

Among 174 patients with bone marrow relapse with or without extramedullary relapse, 4-year disease-free survival was 72.7% ± 5.8% in the blinatumomab group vs 53.7% ± 6.7% in the chemotherapy group (P = .0150) and 4-year overall survival was 97.1% ± 2.1% vs 84.8% ± 4.8% (P = .020).

Among 81 patients with isolated extramedullary relapse, 4-year disease-free survival was 36.6% ± 8.2% vs 38.8% ± 8.0% (P = .62) and 4-year overall survival was 76.5% ± 7.5% vs 68.8% ± 8.6% (P = .53).

Blinatumomab was well tolerated, with low adverse event rates being reported.

The investigators concluded, “For children, adolescents, and young adults with B-ALL in low-risk first relapse, there was no statistically significant difference in disease-free survival or overall survival between the blinatumomab and standard chemotherapy arms overall. However, blinatumomab significantly improved disease-free survival and overall survival for the two-thirds of patients with [bone marrow relapse with or without extramedullary relapse], establishing a new standard of care for this population. By contrast, similar outcomes and poor disease-free survival for both arms were observed in the one-third of patients with isolated extramedullary relapse; new treatment approaches are needed for these patients.”

Laura E. Hogan, MD, of the Department of Pediatrics, Stony Brook Children’s, is the corresponding author for the Journal of Clinical Oncology article.

Disclosure: The study was supported by the National Cancer Institute and St. Baldrick’s Foundation. For full disclosures of the study authors, visit

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