What is Abemaciclib: Uses, Dosage, Side Effects and More

Abemaciclib is a targeted cancer medication that helps slow down the growth of certain breast cancers. It belongs to a class of drugs called CDK4/6 inhibitors, which work by blocking proteins that cancer cells need to multiply and spread.

This medication represents a significant advancement in breast cancer treatment, offering hope to many patients when combined with other therapies. Let's explore everything you need to know about this important medication in a way that's easy to understand.

What is Abemaciclib?

Abemaciclib is an oral cancer medication that targets specific proteins in cancer cells. It's designed to interrupt the cancer cell's ability to divide and grow by blocking two proteins called CDK4 and CDK6.

Think of these proteins as the "go" signals that tell cancer cells to multiply. By blocking these signals, abemaciclib helps slow down or stop the cancer from growing and spreading to other parts of your body.

This medication is considered a targeted therapy, which means it specifically attacks cancer cells rather than affecting all rapidly dividing cells in your body like traditional chemotherapy does.

What is Abemaciclib Used For?

Abemaciclib is primarily used to treat hormone receptor-positive, HER2-negative breast cancer. This specific type of breast cancer grows in response to hormones like estrogen and progesterone.

Your doctor may prescribe this medication in several situations. It's often used when breast cancer has spread to other parts of your body (metastatic breast cancer) or when there's a high risk of the cancer returning after initial treatment.

The medication can be used alone or in combination with other cancer treatments, depending on your specific situation. Your oncologist will determine the best treatment approach based on your cancer's characteristics and your overall health.

How Does Abemaciclib Work?

Abemaciclib works by targeting the cell cycle, which is the process cells go through to divide and multiply. It specifically blocks CDK4 and CDK6 proteins that act like accelerators for cancer cell growth.

When these proteins are blocked, cancer cells get stuck in a phase called G1, where they can't progress to the next step of cell division. This effectively puts the brakes on cancer cell multiplication.

As a targeted therapy, abemaciclib is considered moderately strong but generally causes fewer severe side effects than traditional chemotherapy. It's designed to be more precise in its action, focusing on cancer cells while sparing more healthy cells.

How Should I Take Abemaciclib?

Abemaciclib comes as tablets that you take by mouth, usually twice daily about 12 hours apart. You can take it with or without food, but try to take it the same way each time for consistency.

Swallow the tablets whole with a glass of water. Don't crush, break, or chew them, as this can affect how the medication is absorbed in your body.

Your doctor will start you on a specific dose based on your condition and may adjust it over time. It's important to take the medication exactly as prescribed, even if you're feeling well.

If you vomit within an hour of taking your dose, don't take another dose. Wait until your next scheduled dose time and continue with your regular schedule.

How Long Should I Take Abemaciclib For?

The length of treatment with abemaciclib varies from person to person and depends on how well the medication is working and how you're tolerating it. Some people may take it for months, while others may need it for years.

Your doctor will monitor your response to the medication through regular check-ups, blood tests, and imaging studies. They'll look for signs that the cancer is responding to treatment and watch for any concerning side effects.

Treatment typically continues as long as the medication is helping control your cancer and you're not experiencing unmanageable side effects. Your healthcare team will work with you to find the right balance.

What Are the Side Effects of Abemaciclib?

Like all medications, abemaciclib can cause side effects, though not everyone experiences them. Understanding what to expect can help you feel more prepared and know when to contact your healthcare team.

The most common side effects tend to be manageable with proper support and monitoring from your medical team:

• Diarrhea (the most common side effect, affecting most patients)
• Fatigue and feeling tired
• Nausea and decreased appetite
• Low white blood cell count (neutropenia)
• Headache
• Hair thinning or loss
• Vomiting
• Mouth sores

Your doctor will monitor you closely for these effects and can provide medications or strategies to help manage them. Most side effects are temporary and improve as your body adjusts to the medication.

Some less common but more serious side effects require immediate medical attention. These include severe diarrhea that doesn't improve with treatment, signs of infection like fever or chills, unusual bleeding or bruising, and severe fatigue that interferes with daily activities.

Blood clots, though rare, can occur with abemaciclib. Watch for symptoms like sudden shortness of breath, chest pain, leg swelling, or pain in your calf.

Who Should Not Take Abemaciclib?

Abemaciclib isn't suitable for everyone, and your doctor will carefully evaluate whether it's right for you. Certain medical conditions and situations may make this medication unsafe or less effective.

You shouldn't take abemaciclib if you're allergic to it or any of its ingredients. People with severe liver problems may not be able to take this medication safely, as it's processed through the liver.

Pregnancy and breastfeeding are important considerations. Abemaciclib can harm an unborn baby, so you'll need to use effective birth control during treatment and for some time after stopping the medication.

Your doctor will also consider other medications you're taking, as some drugs can interact with abemaciclib and affect how well it works or increase the risk of side effects.

Abemaciclib Brand Names

Abemaciclib is available under the brand name Verzenio. This is the most commonly prescribed form of the medication and is manufactured by Eli Lilly and Company.

When you receive your prescription, you'll see "Verzenio" on the medication bottle, but the active ingredient is abemaciclib. Both names refer to the same medication.

Your insurance coverage and pharmacy may affect which version you receive, but the active ingredient and effectiveness remain the same regardless of the specific manufacturer.

Abemaciclib Alternatives

While abemaciclib is an important treatment option, there are other medications in the same class that your doctor might consider. These alternatives work similarly but may have different side effect profiles or dosing schedules.

Palbociclib (Ibrance) and ribociclib (Kisqali) are two other CDK4/6 inhibitors that treat similar types of breast cancer. Your doctor might recommend one of these if abemaciclib isn't suitable for you or if you experience intolerable side effects.

The choice between these medications depends on various factors including your specific cancer characteristics, other health conditions, potential drug interactions, and your personal preferences regarding side effects and dosing schedules.

Is Abemaciclib Better Than Palbociclib?

Both abemaciclib and palbociclib are effective CDK4/6 inhibitors, but they have some differences that might make one more suitable for you than the other. Neither is universally "better" – the best choice depends on your individual situation.

Abemaciclib can be taken continuously (every day), while palbociclib is typically taken for 21 days followed by a 7-day break. Some people prefer the continuous dosing, while others appreciate the break period.

The side effect profiles are similar but not identical. Abemaciclib is more likely to cause diarrhea, while palbociclib may be more likely to cause low white blood cell counts that require dose adjustments.

Your oncologist will consider factors like your cancer's specific characteristics, your overall health, other medications you're taking, and your lifestyle when recommending which medication might work best for you.