While the clinical impact of mutations in the ABL1 gene on response to therapy in chronic phase chronic myeloid leukemia (CP-CML) is well established, less is known about how other mutations affect prognosis. In a retrospective analysis, we identified 115 patients with CML (71 chronic, 15 accelerated and 29 blast phase) where targeted next-generation sequencing of genes recurrently mutated in myeloid leukemias was performed. ASXL1 was the most frequently mutated gene in the chronic (14%) and accelerated phase (40%) CML patients, whereas RUNX1 (20%) was the most common mutation in blast phase. Compared with wild-type ASXL1, CP-CML with mutant ASXL1 was associated with worse event-free survival (EFS) (median of 32.8 vs 88.3 months; P = 0.002) and failure-free survival (median of 13.8 vs 57.8 months; P = 0.04). In a multivariate analysis, ASXL1 mutation was the only independent risk factor associated with worse EFS in chronic phase CML with a hazard ratio of 4.25 (95% CI 1.59–11.35, P = 0.004). In conclusion, mutations in ASXL1 are associated with worse outcomes when detected in chronic phase CML.

Mutations in Nucleophosmin 1 (NPM1) are associated with a favorable prognosis in newly diagnosed acute myeloid leukemia (AML), however, their prognostic impact in relapsed/refractory (R/R) settings are unknown. In a retrospective analysis, we identified 206 patients (12%) with mutated NPM1 (NPM1c) and compared their outcomes to 1516 patients (88%) with NPM1 wild-type (NPM1wt). NPM1c was associated with higher rates of complete remission or complete remission with incomplete count recovery compared with NPM1wt following each line of salvage therapy (first salvage, 56% vs 37%; P < .0001; second salvage, 33% vs 22%; P = .02; third salvage, 24% vs 14%; P = .02). However, NPM1 mutations had no impact on relapse-free survival (RFS) and overall survival (OS) with each salvage therapy with a median OS following salvage 1, 2 or 3 therapies in NPM1c vs NPM1wt of 7.8 vs 6.0; 5.3 vs 4.1; and 3.5 vs 3.6 months, respectively. Notably, the addition of venetoclax to salvage regimens in patients with NPM1c improved RFS and OS (median RFS, 15.8 vs 4.6 months; P = .05; median OS, 14.7 vs 5.9 months; P = .02). In conclusion, NPM1 mutational status has a minimal impact on prognosis in relapsed or refractory AML; therefore, novel treatment strategies are required to improve outcomes in this entity.

The BCL-2 inhibitor venetoclax improves survival for adult patients with acute myeloid leukemia (AML) in combination with lower-intensity therapies, but its benefit in pediatric patients with AML remains unclear. We retrospectively reviewed two Texas Medical Center institutions’ experience with venetoclax in 43 pediatric patients with AML; median age 17 years (range, 0.6–21). This population was highly refractory; 44% of patients (n = 19) had ≥3 prior lines of therapy, 37% (n = 16) had received a prior bone marrow transplant, and 81% (n = 35) had unfavorable genetics KMT2A (n = 17), WT1 (n = 13), FLT3-ITD (n = 10), monosomy 7 (n = 5), TP53 (n = 3), Inv(3) (n = 3), IDH1/2 (n = 2), monosomy 5 (n = 1), NUP98 (n = 1) and ASXL1 (n = 1). The majority (86%) received venetoclax with a hypomethylating agent. Grade 3 or 4 adverse events included febrile neutropenia in 37% (n = 16), non-febrile neutropenia in 12% (n = 5), anemia in 14% (n = 6), and thrombocytopenia in 14% (n = 6). Of 40 patients evaluable for response, 10 patients (25%) achieved complete response (CR), 6 patients (15%) achieved CR with incomplete blood count recovery (CRi), and 2 patients (5%) had a partial response, (CR/CRi composite = 40%; ORR = 45%). Eleven (25%) patients received a hematopoietic stem cell transplant following venetoclax combination therapy, and six remain alive (median follow-up time 33.6 months). Median event-free survival and overall survival duration was 3.7 months and 8.7 months, respectively. Our findings suggest that in pediatric patients with AML, venetoclax is well-tolerated, with a safety profile similar to that in adults. More studies are needed to establish an optimal venetoclax-based regimen for the pediatric population.