Outcome of second-line therapy in adult B-cell acute lymphoblastic leukemia.

[BACKGROUND AND STUDY AIMS] Historically, adults with B-cell acute lymphoblastic leukemia (ALL) treated with standard intensive chemotherapy in first salvage had a complete response rate of 40% and a 3-year survival rate <10%. The outcome of B-cell ALL on second-line therapy (salvage 1) is changing rapidly with the introduction of novel strategies into both frontline and salvage therapy. The study aim is to define the outcome of adult B-cell ALL on second-line therapy and its predictors in the novel era of ALL therapy.

[PATIENTS AND METHODS] A total of 372 adults with B-cell ALL in salvage 1 treated from 2000 until 2024 were analyzed.

[RESULTS] The complete remission (CR) rate was 70%; the 3-year survival rate was 30%. By multivariate analysis, the independent adverse predictors for CR were thrombocytopenia, unfavorable karyotype, and older era of therapy; combination of chemotherapy plus blinatumomab/inotuzumab was independently favorable. The independent adverse predictors of survival were older age, unfavorable karyotype, thrombocytopenia, and shorter duration of first CR; again, combination of chemotherapy plus blinatumomab/inotuzumab was independently favorable. Combination of chemotherapy and blinatumomab/inotuzumab was associated with a CR rate of 96% and a 3-year survival rate of 52%.

[CONCLUSIONS] This study establishes a modern expectation of outcome of adult B-cell ALL treated in salvage 1. Combination of chemotherapy and blinatumomab/inotuzumab should be a standard of care in adult B-cell ALL in salvage 1.