Abemaciclib (Verzenio) for breast cancer: the complete patient guide

Abemaciclib, known by the brand name Verzenio, or Verzenios in some countries, is a targeted tablet for hormone receptor positive, HER2-negative breast cancer. It belongs to the CDK4/6 inhibitor group, which blocks two proteins that cancer cells use to keep dividing. It is taken together with hormone therapy, such as an aromatase inhibitor or fulvestrant, and the combination works better than hormone therapy on its own. In early breast cancer, abemaciclib is taken for two years after surgery by people whose cancer has spread to lymph nodes and has a higher chance of returning. In advanced or metastatic breast cancer, it is taken for as long as it keeps the cancer under control and the side effects are manageable. The tablets are swallowed twice a day, roughly twelve hours apart, every day without a break, with or without food. The side effect most people notice is loose motions, usually in the first weeks, which is why an anti-diarrhoea medicine such as loperamide is kept at home from the first day. Blood counts, liver tests and kidney tests are checked regularly, especially in the first few months. Tiredness, feeling sick and a lower white cell count are also common. Most side effects can be managed with simple measures or by adjusting the dose, and many people continue their normal routine during treatment.

Always with hormone therapy

Abemaciclib and hormone therapy are a team. Keep taking both exactly as prescribed, and do not stop either on your own.

Loose motions are expected

Start the anti-diarrhoea medicine at the first loose stool, drink plenty of fluids, and tell your team the same day.

Regular blood tests

Checks are frequent in the first months and then spaced out once things are settled.

Abemaciclib helps many people, but it asks something of you in return, and it is better to know that from the start.

The first months are the hardest

Loose motions and tiredness tend to be worst early on. Many people find treatment easier once the dose is settled and they know how to handle bowel changes.

Dose changes are normal

Many people need a lower dose at some point. Studies suggest a lower dose does not seem to take away the benefit, so a reduction is not a failure.

It lowers risk but cannot remove it

In early breast cancer, abemaciclib lowers the chance of the cancer returning, but some people still have a recurrence. In advanced disease, it controls the cancer for a period rather than for good.

What this page cannot tell you

It cannot tell you how much abemaciclib would help you, or which dose you need. Your oncologist can explain this using your own reports.

Regular checks catch side effects early, often before you notice them.

Blood tests

A full blood count and liver tests are usually checked before starting, about every two weeks for the first couple of months, monthly for the next couple of months, and then as your doctor advises.

Kidney tests

Creatinine can rise slightly because abemaciclib affects how the kidney clears it. Your doctor may use other tests to check that the kidneys are really working well.

Scans in advanced disease

Scans are repeated every few months to check whether the cancer is under control.

Pregnancy and contraception

Abemaciclib can harm an unborn baby. Use reliable non-hormonal contraception during treatment and for at least three weeks after the last dose, and do not breastfeed.