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

Selpercatinib is a targeted cancer medication that blocks specific proteins helping certain tumors grow. This oral medication represents a major breakthrough for people with lung cancer and thyroid cancer that have particular genetic changes called RET alterations.

If your doctor has prescribed selpercatinib, you're likely dealing with a cancer that has shown these specific genetic markers. This medication works differently from traditional chemotherapy by targeting only the cancer cells with these changes, which often means fewer side effects for you.

What is Selpercatinib?

Selpercatinib belongs to a class of medications called RET inhibitors. It's designed to block abnormal RET proteins that fuel cancer growth in certain patients.

The medication comes as capsules you take by mouth. It was specifically developed through precision medicine research, meaning scientists created it to target the exact molecular problem driving your particular type of cancer. This targeted approach often works better than older treatments that affect healthy cells too.

Think of selpercatinib as a key that fits a very specific lock. The "lock" is the RET protein in your cancer cells, and this medication is designed to fit perfectly and stop the cancer from growing.

What is Selpercatinib Used For?

Selpercatinib treats specific types of cancer that have RET gene changes. Your doctor will have tested your tumor to confirm these genetic alterations before prescribing this medication.

The medication is primarily used for non-small cell lung cancer (NSCLC) with RET gene fusions. This accounts for about 1-2% of all lung cancers, but for patients with this specific type, selpercatinib can be remarkably effective.

It's also approved for medullary thyroid cancer and other thyroid cancers with RET mutations. These represent different types of thyroid cancer that respond well to RET-targeted therapy.

Additionally, selpercatinib may be used for other solid tumors with RET gene alterations. Your oncologist will determine if your specific cancer type qualifies for this treatment based on genetic testing results.

How Does Selpercatinib Work?

Selpercatinib blocks the RET protein pathway that cancer cells use to grow and multiply. When RET proteins become abnormal due to genetic changes, they send constant "grow" signals to cancer cells.

This medication acts like a stop sign for those growth signals. By blocking the RET protein, selpercatinib can slow down or stop cancer cell division, potentially shrinking tumors or preventing them from growing larger.

The medication is considered a strong, highly selective RET inhibitor. This means it's very good at hitting its target while leaving other cellular processes relatively undisturbed. This selectivity is why many patients experience fewer side effects compared to traditional chemotherapy.

Your cancer cells become dependent on these abnormal RET signals to survive. When selpercatinib blocks these signals, the cancer cells often die or stop growing, which is why this medication can be so effective for the right patients.

How Should I Take Selpercatinib?

Take selpercatinib exactly as your doctor prescribes, usually twice daily with or without food. The typical starting dose is 160 mg twice daily, but your doctor may adjust this based on your response and any side effects.

You can take the capsules with water, milk, or juice. There's no need to avoid food when taking this medication, which makes it easier to fit into your daily routine. However, try to take it at the same times each day to maintain consistent levels in your system.

Swallow the capsules whole without opening, crushing, or chewing them. If you have trouble swallowing pills, talk to your healthcare team about strategies that might help, but don't alter the capsules yourself.

If you vomit after taking a dose, don't take another dose right away. Wait until your next scheduled dose time. Keep taking the medication even if you start feeling better, as cancer medications work best when taken consistently.

How Long Should I Take Selpercatinib For?

You'll typically take selpercatinib for as long as it's working and you're tolerating it well. This could be months or even years, depending on how your cancer responds.

Your doctor will monitor your progress through regular scans and blood tests. These appointments help determine if the medication is shrinking your tumors or keeping them stable. As long as selpercatinib is helping control your cancer without causing serious side effects, you'll likely continue taking it.

Some patients take this medication for extended periods with good quality of life. Others may need dose adjustments or breaks if side effects become challenging. Your oncologist will work with you to find the right balance.

Never stop taking selpercatinib without discussing it with your doctor first. Even if you feel well, the medication may still be working to control cancer cells you can't see or feel.

What Are the Side Effects of Selpercatinib?

Most people taking selpercatinib experience some side effects, but they're often manageable with proper support. The good news is that serious side effects are less common than with traditional chemotherapy.

Here are the most common side effects you might experience, and it's important to know that your healthcare team can help manage each of these:

• Dry mouth occurs in about 60% of patients but can be managed with frequent water sips and oral care
• Diarrhea affects roughly half of patients and usually responds well to dietary changes and medications
• High blood pressure develops in about 40% of patients and can be controlled with blood pressure medications
• Fatigue is common and often improves as your body adjusts to the medication
• Swelling in hands, feet, or face happens in about 30% of patients
• Rash or skin changes affect some patients but are typically mild

These side effects don't happen to everyone, and when they do occur, they're usually mild to moderate. Your healthcare team will monitor you closely and can adjust your treatment plan if needed.

Less common but more serious side effects can include liver problems, heart rhythm changes, or severe skin reactions. Your doctor will watch for these through regular blood tests and check-ups.

Some rare but serious side effects include severe bleeding, lung problems, or severe allergic reactions. While these are uncommon, it's important to contact your healthcare team immediately if you experience unusual symptoms like difficulty breathing, severe chest pain, or unusual bleeding.

Who Should Not Take Selpercatinib?

Selpercatinib isn't right for everyone, and your doctor will carefully evaluate whether it's safe for you. People with certain heart conditions or liver problems may need special monitoring or alternative treatments.

You should not take selpercatinib if you're allergic to it or any of its ingredients. If you've had severe allergic reactions to similar medications, make sure to discuss this with your oncologist.

Pregnant women should not take selpercatinib as it can harm the developing baby. If you're planning to become pregnant, could be pregnant, or are breastfeeding, discuss this with your doctor before starting treatment.

People with severe liver disease may need dose adjustments or alternative treatments. Your doctor will check your liver function before starting selpercatinib and monitor it regularly during treatment.

If you have a history of heart rhythm problems, your doctor will evaluate whether the benefits outweigh the risks. Some patients may need additional heart monitoring while taking this medication.

Selpercatinib Brand Name

Selpercatinib is sold under the brand name Retevmo. You might see either name on your prescription bottle or in medical records.

Retevmo is manufactured by Eli Lilly and Company. The medication was approved by the FDA in 2020, making it a relatively new but well-studied treatment option.

Whether your prescription says selpercatinib or Retevmo, you're getting the same medication. Some insurance companies or pharmacies may use one name or the other, but the active ingredient and effectiveness are identical.

Selpercatinib Alternatives

If selpercatinib isn't right for you, other treatment options exist depending on your specific cancer type and genetic profile. Your oncologist will help determine the best alternative approach.

For RET-positive lung cancer, other targeted therapies like pralsetinib (Gavreto) might be an option. This is another RET inhibitor that works similarly to selpercatinib but may have a different side effect profile.

Traditional chemotherapy remains an option for many patients, though it typically has more widespread side effects. Immunotherapy drugs like pembrolizumab might also be considered depending on your tumor characteristics.

For thyroid cancers, alternatives might include other targeted therapies like cabozantinib or vandetanib. Radioactive iodine therapy could be an option for certain types of thyroid cancer.

Clinical trials often offer access to newer experimental treatments. Your oncologist can help you explore whether any current trials might be appropriate for your situation.

Is Selpercatinib Better Than Other RET Inhibitors?

Selpercatinib and pralsetinib are both effective RET inhibitors, but they have some differences that might make one more suitable for you than the other. Your doctor will consider your specific situation when choosing between them.

Selpercatinib was the first selective RET inhibitor approved, so doctors have more experience using it. Clinical trials have shown impressive response rates, with many patients seeing their tumors shrink significantly.

The side effect profiles are somewhat different between the two medications. Some patients tolerate one better than the other, which can be an important factor in treatment decisions.

Both medications have shown similar effectiveness in clinical trials, so the choice often comes down to individual factors like your other health conditions, potential drug interactions, and personal preferences about side effects.