Background: MRD negativity is a key prognostic indicator of patient (pt) outcome in ALL and is predictive of improved survival and disease-free status. In the INO-VATE ALL trial (Kantarjian, NEJM 2016), pts with R/R ALL who received InO vs standard chemotherapy (SC) achieved greater remission (CR/CRi; 81% vs 29%) and MRD-negativity (78% vs 28%, in pts with CR/CRi) and had improved overall survival (OS): 7.7 vs 6.7 months. This analysis was conducted to assess prognostic value of MRD negativity by end of treatment (EOT) with InO. Methods: INO-VATE pts who received InO (n = 164) were included. Among pts with CR/CRi, MRD status (by multiparametric flow cytometry at a central lab) was defined as negative (MRD–) if < 1 × 10^-4 blasts/nucleated cells (n = 81), or as positive (MRD+; n = 83), based on assessment by EOT. OS, progression-free survival (PFS), and predictors of MRD status (by multivariate logistic regression) are reported from final study data as of Jan 4, 2017. Results: MRD– status with CR/CRi was associated with significantly improved OS and PFS (Table) vs MRD+ status with CR/CRi: unstratified HR 0.512; 1-sided P= 0.0009 for OS and HR 0.423; P< 0.0001 for PFS. Exploratory multivariate analyses indicated that 2nd salvage compared to 1st salvage (OR 0.499, 2-sided P= 0.058) was associated with lower likelihood of having MRD– status, while < 1x10⁹/L absolute circulating blast count at baseline (OR 3.231, P= 0.002) and longer duration of remission (OR 1.033, P= 0.005) were associated with increased likelihood of having MRD– status. Clinical trial information: NCT01564784Conclusions: Among pts who received InO in the INO-VATE trial, having CR/Cri and MRD– status at EOT was associated with the greatest survival outcomes. However, pts who achieved an MRD+ CR/CRi had much greater survival than those who did not have CR/CRi. In R/R ALL, use of InO may optimize chances to attain the primary goal of complete remission and MRD– status.

*includes 6 pts with no MRD assessment