7 Key Insights From the Veppanu Clinical Study

Written by Tristan Lindfelt, BCOP, BCPS, PharmD
Medically Reviewed by Michelle Vermeulen, PharmD on July 27, 2026
  • Who can take this drug
  • How well it worked in a study
  • What side effects to watch for
  • Who took part in the study

Veppanu was approved in May 2026 for adults with a certain type of breast cancer that is advanced or metastatic. "Advanced" means the cancer has spread beyond where it started. "Metastatic" means it has spread to other parts of the body, like the bones, liver, or lungs.

To take Veppanu, a person's cancer must:

  • Grow because of the hormone estrogen 
  • Not have a protein called HER2
  • Have a gene change called ESR1 (this change can make some hormone treatments stop working)
  • Keep growing even after at least one hormone treatment

How Veppanu works

Some breast cancer cells use a protein called the estrogen receptor to grab on to estrogen and use it as fuel to grow. Veppanu attaches to this receptor and marks it for breakdown inside the cell. With less of the receptor around, the cancer cell has a harder time using estrogen to grow. This matters for tumors with the ESR1 gene change because that change can make other hormone therapies stop working, but Veppanu can still target and break down the receptor even when this change is present.

How do you find out if you have the ESR1 gene change?

Your doctor can order a blood test, sometimes called a liquid biopsy, that checks for this gene change using an FDA-authorized test. Ask your care team whether this kind of testing makes sense for you, especially if your cancer has grown after hormone treatment.

This approval was based on a study called VERITAC-2. People in the study had already tried one or two hormone treatments. They had also tried another type of drug called a CDK4/6 inhibitor, such as abemaciclib, palbociclib, or ribociclib.

In the VERITAC-2 study, people with the ESR1 gene change went a median of five months before their cancer started growing again while taking Veppanu. "Median" means half the patients went longer than five months, and half went less than five months. 

People who took a different drug called fulvestrant went a median of 2.1 months before their cancer grew again. 

Veppanu did not show this benefit in patients without the ESR1 gene change.

Among patients with the ESR1 gene change, 18.6% saw their cancer shrink partly or fully after taking Veppanu. Only 4% of patients taking fulvestrant had the same result. 

 Like most cancer medicines, Veppanu can cause side effects. The most common ones were: 

  • Tiredness: about 1 in 4 patients
  • Changes in liver blood tests: about 1 in 7 patients (this means the liver might not be working as well as usual)
  • Nausea: about 1 in 7 patients

Most of these side effects were mild. Tell your care team if any side effects bother you. They can help you feel better.

Some people had more serious side effects. These included:

  • Anemia (low red blood cells), which makes you feel tired or weak
  •  Low potassium levels
  • Neutropenia, which may make it harder to fight off illness 

Your care team will monitor your blood counts and potassium levels regularly and can adjust your treatment if needed.

When to call your doctor right away

Some side effects need prompt attention. Call your doctor right away if you notice:

  • Signs of a heart rhythm problem: feeling lightheaded or faint, a pounding or fast heartbeat, shortness of breath, or chest pain
  • Signs of a liver problem: yellowing of your skin or eyes, unusually dark urine, or pain in the upper right side of your belly
  • Signs of low potassium: muscle cramps or weakness
  • Signs of infection (which can happen if your white blood cell count is low): fever or chills

These aren't the only side effects to watch for. Always tell your care team about anything new or worsening while you're on Veppanu.

Some patients on Veppanu (about 1 in 10) had a heart change called QT interval prolongation. This is a change in the heart's electrical pattern. Even so, no patients had an irregular heartbeat, also called an arrhythmia. This heart change also happened in fulvestrant patients, but only in about 1 in 100.

Your doctor will check your heart during treatment using a test called an electrocardiogram, or EKG (or ECG).

Almost everyone in the ESR1 gene change group was female, and the average age was around 60. 

  • Among patients who received Veppanu, about 43% were White and 45% were Asian.  
  • More than half already had cancer that spread to internal organs.  
  • Almost everyone had already taken common breast cancer drugs called aromatase inhibitors and CDK4/6 inhibitors, like palbociclib or ribociclib. 

Add WebMD as a Preferred Source to see more of our trusted content across Google Search, AI Overviews, and AI Mode