Background: In R/R ALL, data are limited supporting targeted therapies like InO as first salvage in patients (pts) who had a long first complete remission (CR1). InO, a calicheamicin-conjugated antibody, targets CD22 on ALL blasts. Here we report outcomes in pts with ALL in first salvage (S1) who had a long CR1 before receiving InO vs standard of care chemotherapy (SC). Methods: Adults with CD22+ R/R ALL, stratified by salvage and length of remission (CR1 ≥ or < 12 mos), were randomized to receive InO (n = 164) or SC (n = 162). Methods were previously described (Kantarjian et al, NEJM 2016), with data shown up to the last patient last visit (January 4, 2017). Outcomes including complete remission (CR)/CR with incomplete hematologic recovery (CRi) and overall survival (OS) were determined for S1 pts who achieved CR1 ≥ 12 mos and CR1 ≥ 18 mos. Results: For S1 pts with CR1 ≥ 12 mos or CR1 ≥ 18 mos, InO and SC arms had generally comparable baseline characteristics. For S1 pts with CR1 ≥ 12 mos and CR1 ≥ 18 mos, fewer pts had received a prior stem cell transplant in the InO vs SC arm (10.4% vs 25.0% and 9.7% vs 21.4%). For S1 pts with CR1 ≥ 12 mos and CR1 ≥ 18 mos respectively, InO vs SC treatment led to a higher CR/CRi rate (85.4% vs 27.5% [P< 0.0001] and 83.9% vs 32.1% [P< 0.0001]) and improved OS (HR = 0.547 [P= 0.0086] and 0.504 [P= 0.0163]), with veno-occlusive liver disease reported in 12.5% and 12.9% of InO pts Clinical trial information: NCT01564784Conclusions: Improved outcomes were seen with InO vs SC among S1 pts who had a long first complete remission (CR1 ≥ 12 mos or CR1 ≥ 18 mos), supporting the benefit of InO vs SC in this population.

*In pts achieving CR/CRi MRD = minimal residual disease, NE = Not evaluable, CI = confidence interval, HR = unstratified hazard ratio