Adding blinatumomab to standard chemotherapy improves outcomes for certain children and adolescents/young adults with low-risk B-cell acute lymphoblastic leukemia (B-ALL) in first relapse, according to results from the AALL1331 trial.
Blinatumomab improved disease-free survival (DFS) and overall survival (OS) for patients who had bone marrow (BM) relapse with or without extramedullary (EM) relapse.
This establishes blinatumomab plus chemotherapy as a new standard therapy for this patient group, according to Patrick Brown, MD, of Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins University in Baltimore.
Dr Brown presented these results from AALL1331 at the 2021 American Society of Hematology (ASH) Annual Meeting.
The phase 3 trial (ClinicalTrials.gov Identifier: NCT02101853) enrolled B-ALL patients aged 1 to 30 years who were in first relapse. All patients received reinduction with the UKALLR3 mitoxantrone regimen.2 Patients were then randomly assigned to treatment by risk. Dr Brown presented results in the low-risk patients.
The low-risk patients had BM relapse with or without EM relapse (BM±EM) at least 36 months from their initial diagnosis or isolated EM (IEM) relapse at least 18 months from initial diagnosis and low (<0.1%) BM minimal residual disease at the end of reinduction chemotherapy.
Patients were randomly assigned to a control or experimental treatment arm. In the control group, patients received 2 intensive chemotherapy blocks (blocks 2 and 3 of UKALLR3), followed by continuation and maintenance chemotherapy of UKALLR3.2
In the experimental group, patients received the aforementioned treatment, but with the integration of three 4-week cycles of blinatumomab. One cycle of blinatumomab replaced block 3 chemotherapy, and 2 cycles were added during continuation and maintenance.
Patients with central nervous system (CNS) leukemia at relapse received additional intensified CNS-directed chemotherapy and radiation during maintenance. Those with testicular leukemia that persisted after reinduction received testicular radiation.
A total of 255 low-risk patients were randomly assigned — 127 to the blinatumomab group and 128 to the control group. The median follow-up was 2.9 years.
In the overall cohort and in patients with IEM relapses, the 4-year DFS and OS rates were not significantly different between the treatment arms.
Overall, the 4-year DFS rate was 61.2 ± 5.5% in the blinatumomab arm and 48.2 ± 6.0% in the chemotherapy arm (P =.154). The 4-year OS rate was 91.6 ± 3.0% and 83.3 ± 4.5%, respectively (P =.096).
Among patients with IEM relapses, the 4-year DFS rate was 34.2 ± 8.6% in the blinatumomab arm and 39.3 ± 8.5% in the chemotherapy arm (P =.73). The 4-year OS rate was 81.7 ± 7.0% and 80.8 ± 7.2%, respectively (P =.61).
Among patients with BM±EM relapses, the 4-year DFS and OS rates were significantly better with blinatumomab.
The 4-year DFS rate was 74.0 ± 6.4% in the blinatumomab arm and 51.8 ± 7.9% in the chemotherapy arm (P =.016). The 4-year OS rate was 96.6 ± 2.5% and 84.4 ± 5.6%, respectively (P =.013).
Treatment arm, age at relapse, and time from diagnosis to first relapse were significant predictors of DFS for patients with BM±EM relapses.
Disclosures: This trial was sponsored by the National Cancer Institute, and the blinatumomab was provided by Amgen. Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of disclosures.
Read more of Cancer Therapy Advisor’s coverage of the ASH 2021 meeting by visiting the conference page.
- Brown PA, Ji L, Xu X, et al. A randomized phase 3 trial of blinatumomab vs. chemotherapy as post-reinduction therapy in low risk (LR) first relapse of B-acute lymphoblastic leukemia (B-ALL) in children and adolescents/young adults (AYAs): A report from Children’s Oncology Group Study AALL1331. Presented at ASH 2021; December 11-14, 2021. Abstract 363.
- Parker C, Waters R, Leighton C, et al. Effect of mitoxantrone on outcome of children with first relapse of acute lymphoblastic leukaemia (ALL R3): An open-label randomised trial. Lancet. 2010;376(9757):2009-17. doi:10.1016/S0140-6736(10)62002-8.