Long-term follow-up of blinatumomab in patients with relapsed/refractory Philadelphia chromosome–positive B-cell precursor acute lymphoblastic leukaemia: Final analysis of ALCANTARA study

AimTo evaluate long-term durability of blinatumomab, a BiTE® (bispecific T-cell engager) molecule, in adults with relapsed/refractory (R/R) Philadelphia chromosome–positive (Ph+) B-cell precursor acute lymphoblastic leukaemia (ALL).MethodsIn this final analysis of an open-label, single-arm, phase 2, multicentre ALCANTARA study (NCT02000427), adults (age ≥18 years) with Ph+ ALL who had relapsed or were refractory to at least one TKI were included. The primary endpoint was the proportion of patients who achieved complete remission (CR)/CR with partial haematologic recovery (CRh) during the first two cycles of blinatumomab treatment.ResultsThe final analysis included 45 patients who completed the study between 3rd January 2014 and 6th January 2017, of which 16 (35.6%; 95% CI, 21.9%–51.2%) achieved CR/CRh within the first two blinatumomab cycles. After a median follow-up of 16.1 months, median relapse-free survival (RFS) was 6.8 (95% CI, 4.4–not estimable [NE]) months. Median overall survival (OS) was 9.0 (95% CI, 5.7–13.5) months with a median follow-up of 25.1 months. Median OS in patients with CR (19.8 [95% CI, 12.1–NE] months) was greater than in those without CR (6.0 [95% CI, 2.9–7.1] months). Of 16 patients with CR/CRh, 14 achieved complete minimal residual disease (MRD) response; the median duration of complete MRD response was 9.7 (95% CI, 5.2–NE) months. Treatment-related adverse events were consistent with those previously reported.ConclusionLong-term durability of responses to blinatumomab was demonstrated in patients with R/R Ph+ ALL.