How to Know When Kisqali Stops Working — Plus, 5 More Expert Tips for Taking Kisqali

Kisqali (ribociclib) is an oral cancer medication. It’s used to treat breast cancer that’s hormone receptor-positive (HR-positive) and human epidermal growth factor 2-negative (HER2-negative). HR-positive breast cancers rely on hormones like estrogen and progesterone to fuel their growth.

Kisqali works to slow cancer growth in a unique way. It’s a type of targeted therapy that blocks proteins in cancer cells called cyclin-dependent kinases 4 and 6, or CDK 4/6. Kisqali is typically used in combination with a hormone therapy medication, which helps slow cancer growth by blocking or lowering estrogen in the body. This two-pronged approach may help you live longer than if you took hormone therapy by itself.

If you have HR-positive, HER2-negative breast cancer, your cancer specialist may recommend Kisqali as a treatment option. Here, we’ll cover six tips for taking Kisqali, such as when Kisqali is used, how to tell if it's working, and how to manage some of its side effects.

1. Kisqali’s intended uses are rather specific

Kisqali is FDA approved to treat adults with HR-positive, HER2-negative breast cancer that is advanced or metastatic (spread to other parts of the body). Its specific uses are broken down by gender:

• All women: Kisqali can be combined with an aromatase inhibitor to treat breast cancer that hasn't been treated with hormone therapy before. Aromatase inhibitors include medications such as letrozole (Femara) and anastrozole (Arimidex).

• Women who have experienced menopause: Kisqali can be combined with fulvestrant (Faslodex) to treat cancer that hasn’t been treated with hormone therapy before or got worse while being treated with a different hormone therapy medication. Fulvestrant is a hormone therapy medication that’s injected into the muscle; it works by blocking estrogen on breast cancer cells.

• Men: Kisqali can be prescribed to men with breast cancer that hasn’t been treated with or got worse while being treated with hormone therapy. Depending on the situation, Kisqali may be combined with an aromatase inhibitor or fulvestrant.

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• A Kisqali alternative: Discover how Verzenio works to treat hormone receptor-positive, HER2-negative breast cancer.

2. Try to take Kisqali in the morning

It’s recommended to take Kisqali once a day, preferably in the morning. This is because Kisqali can cause QT prolongation, a side effect that can lead to potentially dangerous changes to your heart rhythm.

Taking Kisqali in the morning may help you better recognize symptoms of QT prolongation and seek medical attention if needed. QT prolongation symptoms can include heart palpitations (fluttering in the chest), dizziness, and blurred vision. Seek immediate medical attention if you experience any of these side effects.

Good to know: If your schedule doesn't allow you to take Kisqali in the morning, that’s OK. But try your best to take it at the same time each day. Consistently timed doses are what’s most important.

3. Your cancer specialist will be in charge of figuring out how well Kisqali is working

Your cancer specialist will monitor you closely to determine how well Kisqali is working for you. They’ll assess your blood work and breast cancer tumor markers to see if your cancer is progressing. Your cancer specialist may also monitor your body scans — such as CT scans or bone scans — for additional signs that the cancer is getting better or worse. 

Tumor shrinkage on scans is a common sign that Kisqali is working. In one clinical study, over half of women who took Kisqali with letrozole experienced partial or complete tumor shrinkage. This is compared with 37% of women who took a placebo pill with letrozole.

Let your cancer specialist know if you have any new breast cancer symptoms or pain. These could be signs that Kisqali isn't working. If Kisqali stops working for you or you're having side effects from the medication that aren't manageable, your cancer specialist may discuss other treatment options with you.

4. The time it takes for Kisqali to stop working varies

Metastatic breast cancer usually requires indefinite treatment. It’s normal to take a medication until it stops working or you begin experiencing intolerable side effects. At that point, you’ll likely switch medications.

So you may be wondering how long Kisqali will work for you. People respond to Kisqali differently, so it’s hard to say for sure. But there are a few clinical studies that can give insight into how long you could expect it to work.

A review of research on CDK 4/6 inhibitors found that the median progression-free survival (PFS) was about 25 months (a little over 2 years) among women who had experienced menopause and taken Kisqali with an aromatase inhibitor as their first treatment. (PFS is a measurement that’s commonly used in cancer studies to determine how long a person can go without their cancer getting worse.) Similarly, those who took Kisqali with fulvestrant had a median PFS of about 20 months.

What’s more, among women who had not experienced menopause and had taken Kisqali in combination with hormone therapy, the median PFS was about 24 months. So, in total, the review found that most people who took Kisqali lived for about 2 years before their cancer got worse.

PFS results can vary, though. And they don't define exactly how long it takes for Kisqali to stop working. The duration of response to treatment would be a more accurate measure of how long it takes for Kisqali to stop working, but this data isn’t publicly available.

5. There are ways to manage Kisqali’s side effects and interactions

Like all medications, Kisqali has some potential side effects and medication interactions.

Kisqali side effects

Common Kisqali side effects include:

• Low white blood cell counts

• Nausea

• Infection

• Tiredness

• Diarrhea

• Joint pain

• Hair loss

• Vomiting

• Constipation

• Rash

• Liver problems

Less common but serious Kisqali side effects include:

• Lung problems, like lung inflammation

• Serious skin reactions, like Stevens-Johnson syndrome

• Heart rhythm problems, such as QT prolongation

• Very low white blood cell counts

A few ways to help manage side effects of Kisqali include:

• Wash your hands often and avoid large crowds and anyone who is sick.

• Stay well hydrated and eat a healthy, balanced diet.

• Get enough sleep and rest.

• If you experience diarrhea, avoid spicy or greasy foods and try to eat small amounts of soft, bland foods instead.

Let your healthcare team know if you experience any bothersome side effects while taking Kisqali. Depending on the severity of your side effects, they may recommend lowering your dosage or stopping treatment temporarily. If you experience serious side effects, you may need to stop taking Kisqali altogether.

Kisqali interactions

Kisqali also has the potential to interact with some medications.

Some interactions can make Kisqali less effective. This includes certain antibiotics, such as rifampin (Rifadin), and anti-seizure medications, such as carbamazepine (Tegretol). Other interactions can lead to an increased risk of Kisqali side effects. This happens with antifungal medications like ketoconazole (Nizoral) and antiretroviral medications like ritonavir (Norvir). Medications such as amiodarone (Pacerone) and sotalol (Betapace) can also increase your risk of heart rhythm problems when taken with Kisqali.

Combining Kisqali and grapefruit also poses a risk. Grapefruit and grapefruit juice can raise the amount of Kisqali in your body, putting you at a higher risk of side effects. So it's best to avoid grapefruit while taking Kisqali.

Make sure to share your medication list, including any supplements and over-the-counter (OTC) medications you take, with your healthcare team. They can identify any potential interactions and recommend safer alternatives if needed.

6. Don’t panic if you vomit after taking Kisqali

Nausea and vomiting are common side effects of Kisqali. If you throw up after taking a dose of Kisqali, you don't need to take another dose that day. Focus on feeling better. Then, take the next dose at your regularly scheduled time the following day.

There are a few ways to help manage nausea and vomiting related to Kisqali:

• Eat several small meals during the day (in lieu of a few large ones).

• Take small sips of water throughout the day.

• Don't skip meals, since an empty stomach may worsen nausea.

• Try alternative therapies, such as meditation and acupressure, that may also be helpful.

Let your cancer specialist know if you experience frequent or notable nausea or vomiting while taking Kisqali. There are several anti-nausea medications they may prescribe, such as promethazine or prochlorperazine.

How to save on Kisqali

There are ways to save on Kisqali, which is only available as a brand-name medication. GoodRx can help you navigate the options, such as copay savings cards and patient assistance programs, to help you save money on your prescription:

• Save with a copay savings card. If you have commercial insurance, you may be eligible to pay as little as $25 per Kisqali prescription using a savings card from the manufacturer.

• Save with a free trial. You may be able to qualify for a free treatment cycle of Kisqali with a manufacturer voucher.

• Save through a patient assistance program. If you’re uninsured or underinsured, you may be eligible for Kisqali’s patient assistance program, which offers the medication free of charge.

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Written by:

Sonja Jacobsen, PharmD, BCPS, BCOP

Sonja Jacobsen, PharmD, BCPS, BCOP,  is a clinical oncology pharmacy specialist currently practicing in Seattle. She has been practicing as a pharmacist since 2015 and is licensed to practice in Washington state and North Carolina.

Edited by:

Joshua Murdock, PharmD, BCBBS

Joshua Murdock, PharmD, BCBBS, is a licensed pharmacist in Arizona, Colorado, and Rhode Island. He has worked in the pharmacy industry for more than 10 years and currently serves as a pharmacy editor for GoodRx.

Reviewed by:

Rachel Feaster, PharmD, BCOP, BCPS

Rachel Feaster has over 10 years of professional experience in ambulatory, inpatient, pharmacogenomics, and oncology care. She is board certified in oncology and pharmacotherapy.

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