Among older patients with Philadelphia chromosome-negative, CD22-positive B-cell acute lymphoblastic leukemia (ALL), a chemotherapy-free regimen including inotuzumab ozogamicin and blinatumomab appears to be safe and effective, according to research presented at the ASCO Annual Meeting 2023. The study met its primary endpoint of event-free survival (EFS), suggesting further study of the regimen is warranted.

A previous phase 3 trial indicated that combination inotuzumab ozogamicin and blinatumomab may improve outcomes among patients with relapsed or refractory disease compared with chemotherapy.

Despite these findings, there are limited data on the safety and efficacy of this combination in the front line. For this open-label phase 2 study ( Identifier: NCT03739814), researchers evaluated whether front-line inotuzumab ozogamicin induction followed by blinatumomab consolidation would improve 1-year EFS rates compared with historical controls among patients with Philadelphia chromosome-negative, CD22-positive B-cell ALL.

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Overall, 33 patients were enrolled. The median age was 71 years, 58% of patients were male, and the median CD22 expression was 92%. The majority (58%) of patients had an Eastern Cooperative Oncology Group performance status of 1.

The median follow-up was 22 months. At this point, the median EFS was not reached (95% CI, 17 months-not reached), and the 1-year EFS rate was 75% (95% CI, 61-92). Age of greater than 70 years did not appear to affect the EFS rate (log-rank P =.03). The 1-year overall survival rate was 84% (95% CI, 72-98).

There were 12 adverse events (AEs) in the cohort, including 3 deaths (1 from refractory ALL, 2 in remission). The most common grade 3 or worse AEs were neutrophil count decrease (87.9%), platelet count decrease (72.7%), and anemia (42.4%). There was 1 case of grade 5 encephalopathy and 1 case of grade 5 respiratory failure.

“Outcomes appear superior to approaches using conventional chemotherapy in this population,” said Matthew Joseph Wieduwilt, MD, PhD, of the Atrium Health Wake Forest Baptist Comprehensive Cancer Center in Winston-Salem, North Carolina, who presented the study’s findings.

Disclosures: This research was supported by Pfizer and Amgen. Please see the original reference for a full list of authors’ disclosures.


Wieduwilt MJ, Yin J, Kour O, et al. Chemotherapy-free treatment with inotuzumab ozogamicin and blinatumomab for older adults with newly diagnosed, Ph-negative, CD22-positive, B-cell acute lymphoblastic leukemia: Alliance A041703. ASCO 2023. June 2-6, 2023. Abstract 7006.