For children diagnosed with certain aggressive leukemias, existing therapies often fall devastatingly short. A dual-mutation subtype of pediatric acute myeloid leukemia — carrying both KMT2A gene rearrangements and RAS pathway mutations — has lacked a rational targeted treatment strategy despite being surprisingly common and carrying a distinctly grim prognosis. New preclinical evidence suggests a two-drug combination may begin to address this gap.
Analysis of 1,750 pediatric patients enrolled in Children's Oncology Group (COG) trials revealed RAS pathway mutations in 43% of AML cases — a strikingly high prevalence. Among patients with KMT2A-rearranged AML, the co-occurrence of RAS pathway mutations correlated with reduced complete remission rates, worse event-free and overall survival, and a pattern of early relapse. In laboratory experiments, combining the MEK1/2 inhibitor selumetinib with the menin inhibitor revumenib produced synergistic reductions in cell viability across AML cell lines and patient-derived xenograft (PDX) models, with enhanced apoptosis, cell cycle arrest, and suppression of Myc target gene expression relative to either drug alone. In live animal PDX models, the combination meaningfully reduced leukemia burden versus monotherapy, though it did not extend overall survival beyond menin inhibition alone.
This work sits at the intersection of two rapidly evolving therapeutic areas: menin inhibition, which has already shown clinical promise in KMT2A-rearranged leukemias in adults, and RAS-MAPK pathway targeting, long considered intractable in hematologic malignancies. The synergistic in vitro signal is mechanistically coherent — menin inhibitors disrupt the transcriptional machinery driving leukemia growth, while MEK inhibition blocks survival signaling that RAS mutations constitutively activate. The disconnect between reduced tumor burden and unchanged overall survival in vivo is a meaningful caveat, suggesting resistant clonal dynamics or pharmacokinetic challenges that will need resolution before clinical translation. As a preclinical-only study in pediatric models, these findings are preliminary, but the large COG cohort anchoring the clinical rationale substantially strengthens the justification for advancing toward a phase I combination trial.