The promise of menin inhibitors: from approval to triplet regimens.

Pharmacologic targeting of the menin-KMT2A protein-protein interaction has emerged as a therapeutic breakthrough for acute leukemias harboring KMT2A rearrangements or NPM1 mutations. The first-in-class menin inhibitor (revumenib) achieved accelerated regulatory approval in November 2024 for monotherapy of relapsed/refractory KMT2A rearranged leukemia. Next-generation agents (ziftomenib, bleximenib, enzomenib, BMF-219) have displayed similar composite complete remission rates (20-35%) and overall response rates (45-65%) in heavily pretreated KMT2Ar and NPM1m acute myeloid leukemia (AML) with measurable residual disease (MRD) negativity and prolonged overall survival (5-7 months). While all menin inhibitors result in on-target blast differentiation with clinical sequelae ("differentiation syndrome") in 10% to 20% of patients, not all menin inhibitors are the same, with differing safety, toxicity (heartrate corrected QT interval (QTc) prolongation, cytopenias), and pharmacokinetic profiles. Acquired mutations in the menin gene described in 39% of post-revumenib relapses have not been identified following other inhibitors (ziftomenib, bleximenib), prompting new questions about resistance mechanisms. These promising results swiftly led to the launch of multiple trials of menin inhibitors combined with intensive (cytarabine and anthracycline) and nonintensive (venetoclax and hypomethylating) chemotherapy backbones. To date, these triplets have yielded high response rates (ie, ≥80% in de novo, 50-70% in relapsed) with most patients achieving MRD negativity and prolonged one-year survival. Ongoing/pending phase 3 trials will clarify whether menin blockade should be incorporated into frontline and maintenance regimens for all patients with KMT2A rearranged or NPM1 mutant disease. In the current era, menin inhibition remains a key pillar of the success of precision medicine for AML therapy.