Retevmo: Key Questions to Ask Your Oncologist Before First Fill
Starting a targeted therapy like Selpercatinib (marketed as RETEVMO®) can feel like a major step in your cancer journey. It is important to have clear, structured discussions with your oncologist before beginning treatment. This guide walks you through the key questions to ask so you can start therapy informed, prepared, and confident.
Confirming RET Positivity and Test Type Used
RET-targeted therapy is prescribed only when a RET alteration is confirmed. Today, comprehensive testing methods such as next-generation sequencing (NGS) are commonly used to ensure accurate detection.1
If you have already undergone testing, your oncologist will have reviewed these results. It may still be helpful to clarify how the testing was done.
You may consider asking:
- What type of RET alteration do I have?
- Was my RET alteration identified through NGS or another method?
- Was the testing comprehensive enough to detect other relevant mutations?
- Would repeat or additional testing ever be needed?
Retevmo Fit: Line of Therapy and Alternatives
Your oncologist has recommended RETEVMO® based on the presence of a RET alteration and your overall clinical condition.3 Understanding how this treatment fits into your broader care plan can help you feel more prepared.
Ask where RETEVMO® fits in your treatment plan:
- What makes this treatment suitable for my cancer at this stage?
- Could you help me understand how this treatment works for my type of cancer?
Expected Benefits in Your Specific Cancer Type
Selpercatinib has demonstrated high response rates and durable responses in RET fusion-positive non-small cell lung cancer and thyroid cancers, but individual outcomes vary.3
Discuss realistic expectations:
- What response rate is expected in my cancer type?
- How quickly might I see results?
- What is the expected duration of benefit?
Starting Dose and What a Dose Adjustment Means
Your doctor will prescribe the appropriate dose based on your condition. It is important to take the medicine exactly as advised and understand what to do in day-to-day situations. Dose adjustments are common and are typically based on side effects, liver function, or cardiovascular findings, not treatment failure.3
Understand your dosing plan:
- If I miss a dose or take it late, what should I do?
- Are there any specific instructions on how to take this medicine (with or without food, timing, etc.)?
Baseline Tests Before First Dose
Before starting treatment, your doctor will usually perform baseline tests such as liver function tests, blood pressure measurement, ECG (to assess heart rhythm), and electrolyte levels. These help establish a safe starting point and guide monitoring during therapy.3
You may consider asking:
- Do I need to take any precautions before these tests, such as fasting or adjusting medications?
- Will any of these tests need to be repeated during treatment?
Monitoring During Treatment
While on RETEVMO® (Selpercatinib), your doctor will regularly monitor your health through blood tests, blood pressure checks, and heart rhythm assessments. These help ensure the treatment remains safe and effective over time.3,4
Blood pressure monitoring can be done at home, while other tests (like liver function and ECG) will be done at scheduled visits.
Selpercatinib may increase blood pressure, so regular monitoring is important. This may include home-based tracking in addition to clinic visits. The treatment may also affect heart rhythm (QT interval) and liver function, which are monitored through ECGs and blood tests, especially during the initial phase of therapy.3,4
You may consider asking:
- How should I monitor my blood pressure at home, and what readings should I watch for?
- How should I monitor my blood pressure at home, and what readings should I watch for?
- Are there any symptoms I should watch for that may suggest heart rhythm or liver-related side effects?
- If I notice symptoms like dizziness, palpitations, or unusual fatigue, what should I do immediately?
Side Effects to Report the Same Day
Do not ignore certain symptoms. Ask your doctor which ones require immediate reporting, such as:3,4
- Severe headache or high blood pressure readings
- Fatigue, diarrhea, nausea
- Yellowing of eyes/skin (possible liver involvement)
You may consider asking:
- Which symptoms should I report on the same day without waiting for my next visit?
Interaction Review: Medicines, Supplements, and Foods
Some medicines, supplements, and even certain foods can affect how RETEVMO® (Selpercatinib) works in your body. It is important to review everything you are taking with your doctor before and during treatment.
Discuss all medications and supplements:
- Should I check with the clinic before starting any new diet, medicines or supplements?
- Are there any common medicines or foods I should avoid while on this treatment?
Missed Dose Rules and What Not to Do
If you miss a dose of RETEVMO® (Selpercatinib), do not take an extra dose to make up for it. Take the next dose as scheduled and follow your doctor’s instructions for any missed doses.3
Clarify:
- What should I do if I miss a dose?
Surgery, Dental Work, and Procedure Planning
Treatment with RETEVMO® (Selpercatinib) may affect how the body heals after procedures. It is important to inform your healthcare team about any planned surgeries, dental work, or invasive procedures in advance.3
Therapies may affect healing:
- Do I need to pause treatment before any planned procedure or dental work?
- When is it safe to restart treatment after a procedure?
Scan Schedule and How Response Will Be Reviewed
Regular scans are done during treatment with RETEVMO® (Selpercatinib) to assess how well the therapy is working.5 These help your doctor evaluate response and make any necessary adjustments to your treatment plan.
Ask about imaging:
- How often will scans be done?
- What defines response vs progression?
Refill Timing and Avoiding Treatment Gaps
It is important to ensure a continuous supply of RETEVMO® to avoid interruptions in treatment. Planning refills in advance can help prevent delays and maintain consistent therapy.3
Continuity is critical:
- When should I request refills?
- How much buffer stock should I maintain?
What to Do If Supply Is Delayed
If there is any delay in accessing your medication, it is important to inform your healthcare team promptly. In some cases, access may be supported through structured programs such as Named Patient Programs (NPPs), which help ensure continuity of treatment.6
You may consider asking:
- Who should I contact immediately if I am unable to access my medication on time?
- Are there any support programs or options available to help avoid treatment interruption?
FAQs
FAQs
What is the difference between tissue and liquid biopsy for RET testing?
A tissue biopsy analyzes tumor tissue and has traditionally been used for genetic profiling, but it is invasive, may yield inadequate DNA, and may not fully capture tumor heterogeneity.7
A liquid biopsy uses blood samples to detect circulating tumor DNA and is less invasive, easier to repeat, and may better reflect overall tumor mutations. However, it is not yet widely adopted as a standard method and is generally used when tissue is limited. 7
How often will blood pressure need to be checked at home?
Usually weekly initially, then less frequently if stable, however consult doctor and his advice.
Which common medicines often cause interactions?
Some medicines may interact with RETEVMO® (Selpercatinib) and should be avoided or adjusted. These include certain medicines that affect how drugs are processed in the body, as well as acid-reducing medicines.3
In some cases, your doctor may adjust the dose or timing if these medicines need to be taken together.
What symptoms suggest liver or heart monitoring needs urgent review?
- Liver: Persistent fatigue or yellowing of the eyes or skin. 3,4
- Heart: Palpitations or fainting. 3
What if I vomit after taking a dose?
If you vomit after taking a dose of RETEVMO, do not take an extra dose. Take the next dose of RETEVMO at your scheduled time. Do not automatically retake the dose, confirm with your doctor based on timing.3
Can I fast or change my diet during therapy?
Discuss any major dietary changes with your doctor, some may affect drug absorption or tolerance.
What happens if a dose needs to be held temporarily?
Your healthcare provider may change your dose, temporarily stop, or permanently stop treatment with RETEVMO if you have side effects. Do not change your dose or stop taking RETEVMO unless your healthcare provider tells you.3
How early should I start refill planning for continuous therapy?
Ideally 1–2 weeks before your supply runs out, especially if access depends on special programs.
References:
1. Testing for RET is essential to identify patients who may be eligible for Retevmo. https://retevmo.lilly.com/hcp/testing#test-methods-nsclc
2. Conde E, Hernandez S, Rodriguez Carrillo JL, et al. RETFusion Testing in Patients With NSCLC: The RETING Study. JTO Clin Res Rep. 2024;5(4):100653. Published 2024 Feb 20. doi:10.1016/j.jtocrr.2024.100653
3. Prescribing information. Lilly USA, LLC; 2025. Accessed April 14, 2026. https://www.accessdata.fda.gov/drugsatfda_docs/label/2024/213246s011s013lbl.pdf
4. Nardo M, Gouda MA, Nelson BE, et al. Strategies for mitigating adverse events related to selective RET inhibitors in patients with RET-altered cancers. Cell Rep Med. 2023;4(12):101332. doi:10.1016/j.xcrm.2023.101332
5. Kozower B, Phillips J, Francescatti A, et al. How Often Should Patients with Lung Cancer Have Imaging Tests after Surgery? [Internet] Washington (DC): Patient-Centered Outcomes Research Institute (PCORI); 2019 Oct. Available from: https://www.ncbi.nlm.nih.gov/books/NBK603844/ doi: 10.25302/10.2019.CER.130600727
6. 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
7. Esagian SM, Grigoriadou GI, Nikas IP, et al. Comparison of liquid-based to tissue-based biopsy analysis by targeted next-generation sequencing in advanced non-small cell lung cancer: a comprehensive systematic review. J Cancer Res Clin Oncol. 2020;146(8):2051–2066. doi:10.1007/s00432-020-03267-x
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.
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