Safety and Efficacy of Blinatumomab As Monotherapy Vs Combination Therapy in the Treatment of Relapsed/Refractory Adult ALL: A Systematic Review

Background: Acute lymphoblastic leukemia (ALL) is rare but aggressive. For refractory and relapsed ALL (R/R ALL), various treatment strategies are adopted, of which the use of blinatumomab has shown promising results in recent decades. Blinatumomab is a CD-19 directed CD3 bispecific T-cell engager antibody that has been approved by the FDA for the treatment of both adults and pediatric ALL. We report the efficacy and toxicity of blinatumomab in relapsed and refractory ALL adult patients. Materials/Methods: Following the PRISMA guideline, we performed a comprehensive literature search PubMed, Embase, Cochrane Library, Web of Science, and Clinicaltrials.gov. We used the following keywords, “acute lymphocytic leukemia” and “Blinatumomab” from the inception of data till 06/17/2020. We screened 1199 articles and included 7 trials and 6 retrospective studies. We excluded all case reports, case series, preclinical trials, review articles, and meta-analysis. We extracted the data for efficacy (complete response, relapse, overall survival, etc.) and safety (≥Grade 3 adverse events). Results: A total of 1393 patients with relapsed/refractory ALL were included. Monotherapy: In phase 3 TOWER trial, a total of 405 patients with heavily pretreated B-cell precursor ALL were randomized in a 2:1 ratio to either receive blinatumomab (n=271) or standard of care (SOC) (N=134). The mean age of both groups was 40.8 years and 41.1, respectively. The dose of blinatumomab (9-28 ug/d) was instituted to the intervention group, whereas the control group received investigator-chosen chemotherapy regimens. The CR/CRi rate for both groups was 95/267 (35.5 %) and 27/134 (31.34%), respectively (p