Menin inhibitors are targeted agents currently in clinical development for the treatment of genetically defined subsets of acute leukemia: AML, ALL.
Menin inhibitors are a novel class of targeted therapies for acute leukemias, specifically those driven by KMT2A rearrangements (KMT2Ar) or NPM1 mutations.
These agents represent a major therapeutic advance for patients with KMT2A-rearranged (KMT2Ar) acute leukemia and NPM1-mutated (NPM1m) acute myeloid leukemia (AML), two aggressive subtypes that historically have had poor outcomes in the relapsed/refractory setting.
Menin inhibitors are targeted epigenetic therapies that disrupt the protein-protein interaction between menin encoded by the MEN1 gene and lysine methyltransferase 2A (KMT2A), thereby blocking oncogenic transcriptional programs in genetically defined subsets of acute leukemia.
Menin functions as a critical scaffold protein that binds to the N-terminal region of KMT2A (formerly known as MLL), facilitating recruitment of the KMT2A complex to chromatin and driving expression of oncogenic genes including HOXA9 and MEIS1.
In KMT2A-rearranged leukemias, all fusion proteins retain the menin-binding domain, making them dependent on this interaction for leukemogenesis.
Menin has a tumor suppressor function in endocrine glands.
Menin it is an important co-factor for certain transcription factors and processes.
They play a key role in regulating gene transcription.
These drugs work by disrupting the interaction between the protein menin and KMT2A, which effectively turns off the abnormal gene expression, specifically HOXA and MEIS1, that prevents leukemic cells from maturing into normal blood cells.
They target epigenetic modifiers.
The most common mutation in adults with AML is the NPM1 mutation which occurs in approximately 25 to 30% of adults with AML: a fraction of these patients that have relapsed or have refractory disease and may benefit from these agents.
KMT2a rearrangements are less common occurring in 5 to 10% of adults, and 80% of infants with newly diagnosed AM: These patients could benefit from menin inhibitors.
Menin inhibitors reprogram leukemia cells back to a normal state by shutting down the gene expression programs responsible for causing leukemia.
Germ-line mutations in the gene encoding menin cause the multiple endocrine neoplasia type 1 (MEN1) syndrome, a hereditary condition associated with tumors of the endocrine glands.
Menin is also critical for leukemogenesis in subsets driven by rearrangement of the lysine methyltransferase 2A (KMT2A) gene, previously known as mixed-lineage leukemia (MLL), which encodes an epigenetic modifier.
Leukemias with rearrangements of KMT2A (KMT2Ar) are susceptible to menin inhibition.
These leukemias affect infants, children and adults, and lead to adverse outcomes with current standard therapies.
Targets in acute leukemia that are susceptible to menin inhibition, such as mutated nucleophosmin 1 (NPM1mt), t he most common genetic alteration in adult acute myeloid leukemia (AML).
Menin inhibitors are in clinical development, but common side effects include the differentiation syndrome.
Revumenib (Revuforj): The first-in-class menin inhibitor.
Indication: Adult and pediatric patients (1 year and older) with relapsed or refractory (R/R) acute leukemia harboring a KMT2A translocation.
It is also being reviewed for R/R NPM1-mutated AML.
Ziftomenib (Komzifti): A highly selective oral inhibitor that has shown robust activity, particularly in NPM1-mutated AML.
Bleximenib: A next-generation inhibitor designed to remain effective even against some mutations that cause resistance to other menin inhibitors.
Enzomenib: Currently in Phase 1/2 trials, notable for its potentially favorable safety profile with lower rates of differentiation syndrome and no mandatory dose adjustments when used with antifungal azoles.
Menin inhibitors are transitioning from single-agent use in advanced settings to combination regimens to improve long-term outcomes.
Triplet Regimens: Trials like BEAT-AML and SAVE are combining menin inhibitors with standard treatments like Venetoclax and Azacitidine.
Early results from combinations with intensive chemotherapy (the “7+3” regimen) show high remission rates and are being explored in newly diagnosed patients.
Many patients achieving remission on these agents are able to successfully proceed to a stem cell transplant.
Common Side Effects
Differentiation Syndrome (DS): Occurs when leukemic cells are forced to mature too quickly, causing systemic inflammation; typically managed with steroids.
QTc Prolongation: A potential change in the heart’s electrical rhythm, particularly noted with revumenib.
Cytopenias: Low blood counts, which are common in leukemia treatments.
The development of MEN1 mutations, which can occur as early as two treatment cycles and prevent the inhibitor from binding to the menin protein while allowing the cancer to continue growing.
Newer agents like bleximenib are being developed specifically to overcome these resistance mutations.
In NPM1-mutated AML, mutant NPM1 binds to chromatin sites co-occupied by KMT2A, and menin inhibition disrupts this interaction, leading to degradation of mutant NPM1 and loss of oncogenic function.
By blocking the menin-KMT2A interaction, these small-molecule inhibitors collapse the leukemogenic transcriptional program, downregulate HOXA9/MEIS1 expression, and induce myeloid differentiation and apoptosis of leukemic blasts.
Two menin inhibitors have received FDA approval:
Revumenib (Revuforj): Approved for relapsed/refractory acute leukemia with KMT2A translocation in patients ≥1 year, and for relapsed/refractory AML with susceptible NPM1 mutation when no satisfactory alternative treatment options exist.
Dosing is 160 mg orally twice daily (with strong CYP3A4 inhibitor) or 270 mg twice daily (without inhibitor).
Ziftomenib (Komzifti): Approved for adults with relapsed/refractory NPM1-mutated AML with no satisfactory alternative treatment options.
Dosing is 600 mg orally once daily.
In heavily pretreated relapsed/refractory disease, menin inhibitors as monotherapy demonstrate composite complete remission (CR + CRh) rates of 20-35% and overall response rates (ORR) of 45-65% across both KMT2Ar and NPM1m AML.
Notably, 61-90% of responders achieve measurable residual disease (MRD) negativity, and median overall survival is 5-7 months.
The AUGMENT-101 trial of revumenib in relapsed/refractory NPM1m AML showed a CR+CRh rate of 23.4% and ORR of 46.9% in 64 heavily pretreated adults (75% had prior venetoclax exposure), with median duration of response of 4.7 months.
The KOMET-001 trial of ziftomenib demonstrated a CR/CRh rate of 22% and ORR of 33% in relapsed/refractory NPM1m AML, with 61% of responders achieving MRD negativity.
In newly diagnosed older adults with NPM1m or KMT2Ar AML, the triplet combination of azacitidine + venetoclax + revumenib achieved an ORR of 88.4%, CR+CRh rate of 81.4%, and CR rate of 67.4%, with 100% MRD negativity among evaluable responders.
Combination trials with intensive chemotherapy backbones have yielded response rates ≥80% in newly diagnosed patients and 50-70% in relapsed disease.
Common toxicities include differentiation syndrome (10-25% of patients), which is generally manageable with corticosteroids and supportive care.
QTc prolongation occurs with some agents (particularly revumenib), while ziftomenib demonstrates less clinically significant QTc effects.
Cytopenias, febrile neutropenia, and gastrointestinal symptoms are also reported.
Resistance develops in approximately 39% of patients treated with revumenib, primarily through acquired MEN1 mutations at the drug-binding pocket that reduce inhibitor affinity.
Such mutations have not been observed following ziftomenib or bleximenib treatment, suggesting different resistance mechanisms.
AML guidelines now include both revumenib and ziftomenib as Category 2A recommendations for relapsed/refractory disease in appropriate molecular subsets.