What is a menin inhibitor?

If you or someone you know has recently been diagnosed with leukemia, you might have heard about a new treatment option called a menin inhibitor. 

But what is a menin inhibitor? How does it work? And, which types of leukemia can it be used to treat?

Read on to find out.  

What is a menin inhibitor?

One reason people develop leukemia is that their cells are born normal, but the usual pathway to maturity is blocked by various genetic mutations. As a result, those cells remain immature and live forever. 

I tend to think of those leukemia cells as children who never really grow up. Instead of going off to college and contributing to society, they just sort of hang around your house because they never develop the skills to find a job and be productive.

Some mutations that cause this need a sort of cellular scaffold to become activated. That scaffold is called menin. Menin inhibitors dismantle the scaffold and prevent it from being rebuilt so that cells can resume their normal development process.  

How many genetic mutations do menin inhibitors target?

Several mutations have been identified so far, including KM2TA and NPM1. KM2Ta is common among pediatric cancer patients with acute lymphocytic leukemia.  

Are menin inhibitors approved by the Food and Drug Administration (FDA)?  

A few menin inhibitors have been approved by the FDA, but only very recently. 

• Revumenib was approved by the FDA to treat certain types of leukemia in November 2024.  
• Ziftomenib was approved in October 2025.  

Bleximinib and enzolimib are still in development, as are two other menin inhibitors that haven’t been named yet. 

Which types of leukemia can menin inhibitors treat?

Right now, they’re mainly used to treat acute myeloid leukemia in patients with one of those mutations. Revumenib is used to a lesser extent in some patients with acute lymphocytic leukemia. 

Do menin inhibitors have any side effects?

Yes. The two main ones are: 

1. Differentiation syndrome: This is caused by large numbers of newly maturing cells releasing cytokine, a signaling protein that acts as a chemical messenger for the immune system, prompting it to ramp up. Also known as a “cytokine storm,” differentiation syndrome causes fever, chills, aches, high blood pressure and significantly increased white blood cell counts. It occurs in about 10-15% of patients.
2. QTc prolongation: This is more of an electrical issue with the heart. Also known as “long QT syndrome,” this is when the lower chambers (ventricles) take too long to contract and relax. Symptoms include dizziness, fainting, palpitations, and, in some cases, seizures. This side effect is more common with revumenib.

To treat differentiation syndrome, we pause the menin inhibitor and give patients steroids, a chemotherapy drug called hydroxyurea, and anti-inflammatory drugs until the episode resolves, then restart the menin inhibitor.  

To treat QTc prolongation, we also pause the menin inhibitor, avoid other drugs that can cause it, and sometimes give beta blockers or electrolyte supplements. We monitor the patient’s heart health very closely with EKGs, too, especially after we restart the drug. 

Other side effects include nausea, vomiting, muscle/bone pain and infections. 

Does UT MD Anderson have any clinical trials involving menin inhibitors?

Yes. One of the most exciting is a Phase III study involving the combination of the menin inhibitor bleximinib, a targeted therapy drug called venetoclax and a chemotherapy drug called azacitidine.

Menin inhibitors are not miracle drugs, but they’re a great addition to our treatment tool kit. Combining them with other types of therapy may enable us to give our patients better — or longer-lasting — results.  

Elias Jabbour, M.D., is a leukemia specialist with a particular interest in acute lymphocytic leukemia.

Request an appointment at UT MD Anderson online or call 1-877-632-6789.