An effective reinduction regimen for first relapse of adult acute lymphoblastic leukemia

Current salvage regimens achieve complete remission (CR) in about a third of adults with relapsed/refractory acute lymphoblastic leukemia (ALL), and this represents a major barrier for performing allogeneic hematopoietic stem cell transplant (HSCT), the only potentially curative treatment. We conducted in adults with first relapse of ALL, a prospective clinical trial with intensive regimen derived from the pediatric Berlin-Frankfurt-Muenster-85 protocol, with addition of a continuous infusional multi-agent chemotherapy in phase II induction followed by consolidation with alternating monthly cycles. Objectives of this study included CR rate, leukemia-free survival (LFS) and toxicity of the regimen in adults. We report the outcome of 19 patients (19-51 years of age) treated prospectively on the study, as well as a subsequent cohort of 31 patients (18-53 years of age) treated off the study. Thirteen of 19 (68%) patients from the initial prospective study achieved CR, and the median overall survival (OS) of these 13 CR patients was 10.3 months. The median OS and LFS of all 19 patients were 5.6 and 4.3 months, respectively. The regimen was well tolerated, and no grade 4 non-hematological toxicity was observed. Of the 31 patients treated off the study and analyzed retrospectively, 16 (52%) achieved CR. After including all 50 patients, the CR rate was 58%. The regimen used in this trial appears to be feasible and effective salvage therapy option for adult patients younger than age 55 with relapsed ALL, produced a high CR rate and could facilitate subsequent allogeneic HSCT.