Inotuzumab ozogamicin for MRD eradication in B-ALL: Phase II trial results

Results from the phase II, single-center trial (NCT01371630) evaluating inotuzumab ozogamicin for measurable residual disease (MRD) eradication in adult patients with B-cell acute lymphoblastic leukemia (B-ALL) in morphologic remission with MRD-positivity (N = 37) were published in Blood Cancer Journal by Jabbour et al. The primary outcome was relapse-free survival (RFS). Secondary outcomes included overall survival (OS), MRD-negativity rate, and safety. 

Key data: The overall MRD-negativity rate was 70%; in patients with Philadelphia chromosome (Ph)-negative and -positive B-ALL, the overall MRD-negativity rates were 76% and 65%, respectively. At a median follow-up of 50 months, the median OS was 61 months and median RFS was 40 months. In patients with Ph-negative vs Ph-positive B-ALL, the median OS was 40 months vs 61 months and RFS was 21 months vs 41 months. The most common non-hematologic adverse events (AEs) were aspartate aminotransferase (AST; 51%) and alanine transaminase (ALT; 49%) elevation, and the most common hematologic AEs were thrombocytopenia (70%) and neutropenia (27%). Sinusoidal obstructive syndrome (SOS) occurred in 8% of patients.

Key learning: Low-dose inotuzumab ozogamicin was effective in eradicating MRD in adults with B-ALL in morphologic remission with detectable MRD, though further studies are warranted to confirm