Blinatumomab treatment of older adults with relapsed/refractory B-precursor acute lymphoblastic leukemia: Results from 2 phase 2 studies

Resumen:
BACKGROUNDOlder adults with relapsed/refractory B-precursor acute lymphoblastic leukemia (r/r ALL) are reported to have a poor prognosis and few therapeutic options. In the current study, the authors evaluated treatment with single-agent blinatumomab in adults aged 65 years with r/r ALL. METHODSA total of 261 adults with r/r ALL who were examined across two phase 2 studies received blinatumomab in cycles of 4-week continuous infusion and 2-week treatment-free intervals. The primary endpoint in each study was complete remission (CR) or CR with partial hematologic recovery (CRh) during the first 2 cycles. Data were pooled and analyzed according to patient age at screening (aged 65 years vs aged <65 years). RESULTSOf 36 older adults, 56% (95% confidence interval [95% CI], 38%-72%) achieved CR/CRh during the first 2 cycles compared with 46% (225 patients) (95% CI, 40%-53%) of younger adults. Complete minimal residual disease responses were 60% in older and 70% in younger responders. Three older responders (15%) and 61 younger responders (59%) proceeded to allogeneic hematopoietic stem cell transplantation. Kaplan-Meier curves overlapped for relapse-free and overall survival for both age groups. Older adults were found to have a similar incidence of grade 3 adverse events (AEs) as younger adults (86% vs 80%) but more grade 3 neurologic events (28% vs 13%). Cytokine release syndrome occurred in 7 older (19%) (1 case of grade 3) and 23 younger (10%) (4 cases of grade 3) adults. There were no treatment-related fatal AEs reported. CONCLUSIONSOlder adults with r/r ALL who were treated with single-agent blinatumomab were found to have similar hematologic response rates and incidence of grade 3 AEs compared with younger adults but had more neurologic events, which were reversible and primarily resolved with treatment interruption. Cancer 2016;122:2178-85. (c) 2016 American Cancer Society. Older adults with relapsed/refractory B-precursor acute lymphoblastic leukemia typically have a worse prognosis and fewer therapy options compared with younger patients. In this analysis of pooled data from two phase 2 studies of single-agent blinatumomab therapy in patients with this disease, older (aged 65 years) and younger (aged <65 years) adults had similar treatment outcomes.