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

Crizotinib is a targeted cancer medication that helps slow the growth of certain types of lung cancer. It works by blocking specific proteins that cancer cells need to grow and spread throughout your body.

This medication represents a significant advancement in personalized cancer treatment. Your doctor will typically order genetic testing of your tumor before prescribing crizotinib to ensure it's the right fit for your specific cancer type.

What is Crizotinib?

Crizotinib is an oral cancer medication that belongs to a class of drugs called tyrosine kinase inhibitors. It specifically targets cancer cells while causing less damage to healthy cells compared to traditional chemotherapy.

The medication comes in capsule form and is taken by mouth twice daily. It was first approved by the FDA in 2011 and has since helped thousands of patients with specific types of lung cancer live longer, healthier lives.

Think of crizotinib as a very precise tool that can identify and block the specific signals that tell certain cancer cells to grow. This targeted approach often means fewer side effects than broader cancer treatments.

What is Crizotinib Used For?

Crizotinib is primarily used to treat non-small cell lung cancer (NSCLC) that has specific genetic changes. Your cancer must test positive for either ALK gene rearrangements or ROS1 gene rearrangements for this medication to be effective.

The medication is typically prescribed when cancer has spread to other parts of your body or when surgery isn't an option. It's considered a first-line treatment, meaning it's often the first medication your doctor will try for these specific cancer types.

In some cases, crizotinib may also be used for certain rare cancers that have ALK gene changes, such as inflammatory myofibroblastic tumors. Your oncologist will determine if your specific cancer type and genetic makeup make you a good candidate for this treatment.

How Does Crizotinib Work?

Crizotinib works by blocking abnormal proteins that cancer cells use to grow and multiply. Specifically, it targets ALK and ROS1 proteins that have become overactive due to genetic changes in your cancer cells.

This medication is considered a moderately strong cancer treatment that's more targeted than traditional chemotherapy. It interferes with the cancer cell's ability to receive growth signals, essentially starving the cancer cells of what they need to survive and spread.

The beauty of crizotinib lies in its precision. While traditional chemotherapy affects both healthy and cancerous cells, crizotinib primarily targets cells with specific genetic abnormalities. This targeted approach often leads to better outcomes with fewer severe side effects.

How Should I Take Crizotinib?

Take crizotinib exactly as your doctor prescribes, typically twice daily with or without food. Swallow the capsules whole with a full glass of water, and don't crush, chew, or open them.

You can take crizotinib with meals if it upsets your stomach, though food isn't required for absorption. Many patients find that taking it with a light snack helps reduce nausea, which is a common side effect.

Try to take your doses at the same times each day, about 12 hours apart. This helps maintain steady levels of the medication in your bloodstream. If you're taking other medications, discuss timing with your doctor to avoid potential interactions.

Avoid grapefruit and grapefruit juice while taking crizotinib, as they can increase the amount of medication in your blood and potentially cause more side effects.

How Long Should I Take Crizotinib For?

Most patients continue taking crizotinib for as long as it's controlling their cancer and the side effects remain manageable. This could be months to years, depending on how well your cancer responds to treatment.

Your doctor will monitor your progress through regular scans and blood tests, typically every 2-3 months initially. These tests help determine if the medication is working effectively and whether you should continue treatment.

Some patients may need to take breaks from crizotinib if side effects become too severe, while others may eventually switch to different medications if their cancer develops resistance. Your treatment plan will be personalized based on your response and overall health.

What Are the Side Effects of Crizotinib?

Like all cancer medications, crizotinib can cause side effects, though not everyone experiences them. Most side effects are manageable and often improve as your body adjusts to the medication.

Here are the most common side effects you might experience:

• Nausea and vomiting
• Diarrhea or constipation
• Fatigue and weakness
• Swelling in legs, ankles, or around the eyes
• Vision changes, including blurred vision or seeing flashes of light
• Dizziness or lightheadedness
• Decreased appetite
• Skin rash

These common side effects are usually mild to moderate and can often be managed with supportive care or medication adjustments.

More serious side effects can occur, though they're less common. It's important to be aware of these so you can seek medical attention if needed:

• Liver problems (yellowing of skin or eyes, dark urine, severe fatigue)
• Lung inflammation (new or worsening cough, shortness of breath, chest pain)
• Heart rhythm problems (irregular heartbeat, chest pain, fainting)
• Severe kidney problems (changes in urination, swelling)
• Severe allergic reactions (difficulty breathing, severe rash, swelling of face or throat)

Contact your healthcare team immediately if you experience any of these serious side effects. They can provide guidance and adjust your treatment if necessary.

Who Should Not Take Crizotinib?

Crizotinib isn't suitable for everyone, and certain medical conditions or circumstances may make it unsafe for you. Your doctor will carefully evaluate your overall health before prescribing this medication.

You should not take crizotinib if you're allergic to the medication or any of its ingredients. Additionally, pregnant women should avoid crizotinib as it can harm the developing baby.

People with certain medical conditions need extra caution or may not be candidates for crizotinib treatment:

• Severe liver disease or liver impairment
• Severe kidney disease
• Heart rhythm disorders or significant heart disease
• Active lung disease or breathing problems
• Pregnancy or breastfeeding

Your doctor will also consider your other medications, as crizotinib can interact with many drugs. Always provide a complete list of all medications, supplements, and herbal products you're taking.

Crizotinib Brand Names

Crizotinib is sold under the brand name Xalkori in the United States and most other countries. This is the original brand name developed by Pfizer, the pharmaceutical company that created the medication.

You may also see crizotinib referred to by its generic name in medical literature or when discussing treatment options with your healthcare team. Both names refer to the same medication with identical active ingredients.

Generic versions of crizotinib may become available in the future, but currently, Xalkori is the primary brand available in most markets.

Crizotinib Alternatives

Several alternative medications are available for treating ALK-positive and ROS1-positive lung cancers. Your doctor might consider these if crizotinib isn't suitable for you or if your cancer develops resistance.

For ALK-positive lung cancer, alternatives include alectinib (Alecensa), ceritinib (Zykadia), and brigatinib (Alunbrig). These newer medications are sometimes used as first-line treatments or when crizotinib stops working.

Traditional chemotherapy remains an option, though targeted therapies like crizotinib often provide better outcomes with fewer side effects for patients with the right genetic markers. Your oncologist will help determine the best treatment approach for your specific situation.

Is Crizotinib Better Than Alectinib?

Both crizotinib and alectinib are effective treatments for ALK-positive lung cancer, but recent studies suggest alectinib may have some advantages as a first-line treatment. The choice between them depends on your specific situation and medical history.

Alectinib appears to be more effective at preventing cancer from spreading to the brain and may cause fewer side effects for some patients. However, crizotinib has been used longer and has extensive real-world experience supporting its effectiveness.

Your oncologist will consider factors like your overall health, other medical conditions, potential side effects, and your personal preferences when choosing between these medications. Both are excellent options for treating ALK-positive lung cancer.