Retsevmo (selpercatinib): Uses, Side Effects, Dosage & Reviews
In some cancers, tiny changes in a gene called RET (rearranged during transfection) can act like a stuck “on” switch, telling cells to grow and divide out of control. These RET alterations are most common in certain types of lung and thyroid cancers, driving tumour growth and survival by activating growth signals. These genetic changes can be identified using advanced testing, and this has opened the door to targeted treatments that can block the faulty signal directly. Retsevmo (selpercatinib) is one such targeted RET inhibitor that was developed to specifically block RET signalling in cancers with RET alterations – representing a major step forward in precision oncology for these patients.1
What is Retsevmo (selpercatinib) and How Does It Work?
Retsevmo is a targeted cancer medicine that contains selpercatinib, a highly selective RET inhibitor. It is designed specifically for cancers driven by abnormal changes in the RET gene.2,3
Retsevmo works by binding to the abnormal RET protein and blocking its activity. By shutting down this growth signal, it can slow tumour progression and, in many cases, shrink tumours. Because it specifically targets RET alterations, it is considered a form of precision medicine – meaning it is used only in patients whose tumours test positive for RET changes.2,3
Retsevmo: Approved Indications
Retsevmo is approved for certain advanced cancers that have a confirmed RET gene alteration, identified through an approved diagnostic test. It is used in the following cases4:
- Adults with locally advanced non-small cell lung cancer (NSCLC) or NSCLC that has spread
- Adults and children (2 years and older) with advanced medullary thyroid cancer (MTC) or MTC that has spread, who require medication by mouth or injection (systemic therapy)
- Adults and children (2 years and older) with advanced thyroid cancer or thyroid cancer that has spread who no longer responds to radioactive iodine treatment and require systemic therapy
- Adults and children (2 years and older) with locally advanced solid tumours or solid tumours that have spread and have gotten worse (progressed) after prior treatment or when no other treatment options are available.
Clinical studies showed that Retsevmo helped control cancer growth and shrink tumours in many patients with RET-positive cancer.3
Who Can Take Retsevmo (RET Testing)
Retsevmo is only used for cancers that have a confirmed RET gene alteration. To find this out, your doctor will order a biomarker test, which is a type of genetic test that looks at your cancer’s DNA. Biomarker testing helps your doctor understand what is driving your cancer’s growth and whether a targeted treatment like Retsevmo may be appropriate.4
To perform this test, your doctor may need a sample of your tumour. This is usually done through a biopsy, where a small piece of tumour tissue – or sometimes a blood sample – is collected and sent to a laboratory for analysis. Some biopsies are minor procedures. Others may require sedation or a short surgical procedure. Like any medical procedure, biopsies can carry a risk of infection.4
If you’ve already had a biopsy in the past, your doctor may be able to use stored tumour tissue for RET testing, meaning you may not need another procedure.4
Your healthcare team will decide the most appropriate type of testing based on your specific situation.
Retsevmo Dosage and Schedule
Retsevmo is taken by itself – it is not combined with other cancer medicines as part of its standard use. It is usually taken twice a day, about 12 hours apart. Your doctor will prescribe the dose that is right for you based on your condition, age, weight, and overall health. Take Retsevmo exactly as your doctor tells you to.4
- Do not change your dose on your own.
- Do not stop taking Retsevmo unless your doctor tells you to.
- Your doctor may adjust your dose if needed, especially if you experience side effects.
How to Take Retsevmo4
- Retsevmo is taken by mouth.
- It can be taken at home.
- It may be taken with or without food.
- Try to take each dose about 12 hours apart to keep the medication levels steady.
- Swallow the capsules whole. Do not crush, chew, or break them.
- Retsevmo capsules should not be given to children who are unable to swallow capsules whole
If you miss a dose and it’s close to your next dose, skip the missed one and continue your normal schedule. Do not double up.4 Follow your prescribing instructions carefully and ask your care team if you are unsure.
Drug Interactions
Before starting Retsevmo, tell your healthcare provider about all the medicines you take, including4
- Prescription medicines
- Over-the-counter medicines
- Vitamins
- Herbal supplements
Retsevmo can affect how other medicines work, and some medicines can affect how Retsevmo works. This may increase your risk of side effects or make treatment less effective. During treatment with Retsevmo, you should avoid the following4:
- St. John’s wort (an herbal supplement)
- Proton pump inhibitors such as dexlansoprazole, esomeprazole, lansoprazole, omeprazole, pantoprazole, and rabeprazole
- H2 blockers such as famotidine, nizatidine, and cimetidine
- Antacids that contain aluminium, magnesium, calcium, simethicone, or buffered medicines
These medications can interfere with how Retsevmo is absorbed or processed in your body. If you take medicine for heartburn, acid reflux, or stomach issues, talk to your doctor. They may recommend an alternative or adjust how you take it.4
Never start or stop any medication while on Retsevmo without checking with your healthcare provider first.
Dose Reductions and Treatment Holds
To keep your treatment as safe and tolerable as possible3:
- Your doctor may reduce your dose if side effects become bothersome or serious.
- In some cases, treatment may be paused temporarily (a treatment hold) if needed.
- If side effects are severe or do not improve, your care team may decide to stop treatment permanently.
Dose changes are individualized – they help you stay on treatment safely.3
Common Side Effects of Retsevmo
Like all cancer treatments, Retsevmo can cause side effects. Some of the more commonly reported ones include oedema, diarrhoea, fatigue, dry mouth, high blood pressure, abdominal pain, constipation, rash, nausea, and headache.3
Besides these side effects, children may experience musculoskeletal pain, fever, vomiting, cough, coronavirus infection and upper respiratory tract infection.3
Most of these are mild to moderate and can be managed with supportive care. Tell your care team about any symptoms you experience so they can help you manage them.
Serious Side Effects and Warnings
While less common, Retsevmo may cause serious problems that require prompt medical attention. These include liver problems, lung inflammation (pneumonitis), heart rhythm changes (QT prolongation), blood clotting or bleeding problems and severe allergic reactions.3
Your care team will monitor for these and act quickly if they occur.
What to Expect During Treatment Monitoring
When you’re on Retsevmo, your healthcare team will keep an eye on3
- Blood pressure
- Blood tests (including liver enzymes)
- Heart rhythm (if needed)
- Symptoms like cough, shortness of breath, fatigue
These checks help catch side effects early so your treatment can continue safely.
Accessing Retsevmo in India Through the Named Patient Program
Retsevmo is approved in many countries; however, availability may vary across regions in India. In situations where suitable local treatment options are limited, eligible patients may be able to access Retsevmo through the Named Patient Program (NPP).5
Under the NPP, a treating oncologist can request Retsevmo for an individual patient by submitting relevant medical records, confirmation of RET-positive status through approved testing, and a clinical justification for use. This process involves regulatory approvals and co-ordinated import before the medicine is supplied to the treating hospital or centre.
Support services such as Rx4U may assist patients and caregivers with documentation, coordination with healthcare providers, and managing import and delivery logistics. This can help streamline the process and reduce administrative delays.
Final Takeaway
- Retsevmo is a targeted therapy designed for cancers with confirmed RET gene alterations.
- It is approved for certain advanced lung cancers, thyroid cancers, and other RET-positive solid tumours.
- Genetic (biomarker) testing is essential before starting treatment.
- In India, access may be possible through the Named Patient Program with physician approval.
- Support services such as Rx4U may help manage documentation and import coordination where required.
Frequently Asked Questions
1. How do I know if Retsevmo is right for me?
Retsevmo is only used if your cancer tests positive for a RET gene fusion or mutation. Your doctor will arrange biomarker testing to confirm this before starting treatment.3,4
2. How is Retsevmo taken?
Retsevmo is taken by mouth, usually twice a day, about 12 hours apart. It is taken on its own and can be taken with or without food. Always follow your doctor’s instructions.4
3. Can Retsevmo be used during pregnancy?
Retsevmo may harm an unborn baby. Women who are pregnant or planning to become pregnant should speak with their doctor. Effective contraception is recommended during treatment and for a period after the last dose.3
4. Can I breastfeed while taking Retsevmo?
Breastfeeding is not recommended during treatment with Retsevmo and for some time after the final dose, as it is not known whether the medicine passes into breast milk and could harm a baby.3 Speak with your doctor about when it may be safe to resume breastfeeding.
Medical Disclaimer
This information is provided for educational purposes only and is not a substitute for professional medical advice. Retsevmo should only be taken under the guidance of a qualified healthcare provider. Patients should always consult their doctor or pharmacist for advice on diagnosis, treatment, and medication use, and should not make changes to their prescribed therapy without medical supervision.
References:
1. Desilets A, Repetto M, Yang SR, Sherman EJ, Drilon A. RET-altered cancers-a tumor-agnostic review of biology, diagnosis and targeted therapy activity. Cancers (Basel). 2023;15(16):4146. doi:10.3390/cancers15164146
2. Raj PE, Bhaskar R, Anne S. Selpercatinib: A narrative drug review. Cancer Res Stat Treat. 2024;7(1):82-90. doi:10.4103/crst.crst_389_23
3. Prescribing information. Lilly USA, LLC; 2025. Accessed February 20, 2026. https://pi.lilly.com/us/Retsevmo-uspi.pdf
4. Retsevmo – a guide for patients and caregivers. Lilly USA, LLC. Accessed February 20, 2026. https://Retsevmo.lilly.com/assets/pdf/all-indications-patient-brochure.pdf
5. Patil S. Early access programs: benefits, challenges, and key considerations for successful implementation. Perspect Clin Res. 2016;7(1):4-8. doi:10.4103/2229-3485.173779
Note:
This information is provided for educational purposes only and is not a substitute for professional medical advice. Retsevmo should only be taken under the guidance of a qualified healthcare provider. Patients should always consult their doctor or pharmacist for advice on diagnosis, treatment, and medication use, and should not make changes to their prescribed therapy without medical supervision.
Disclaimer:
Rx4U procures prescribed medicines directly from manufacturers or authorized distributors. It does not claim ownership of any trademarks and complies with the provisions of the Trademark Act, 1999, particularly Sections 30 and 30(1) concerning ‘Fair Use’. It solely facilitates access to new launches through named patient import.
