What is Selpercatinib used for?

Selpercatinib, also marketed under the trade name Retevmo, is a groundbreaking targeted therapy that has been a game-changer in the landscape of cancer treatment. Developed by Loxo Oncology, in collaboration with Eli Lilly and Company, this drug belongs to a class of medications known as tyrosine kinase inhibitors (TKIs). It specifically targets cancers that have alterations in the RET gene, making it a highly specialized form of treatment. Selpercatinib has been FDA-approved for the treatment of non-small cell lung cancer (NSCLC), medullary thyroid cancer (MTC), and other types of thyroid cancers that have RET gene mutations or fusions. The research and development behind this drug have shown promising results, with significant progress in clinical trials, leading to its approval for use in various oncological settings.

The mechanism of action for Selpercatinib revolves around its ability to inhibit the activity of the RET protein, which is often mutated or abnormally active in certain types of cancer. RET, short for "rearranged during transfection," is a gene that encodes a protein involved in cell growth and differentiation. When this gene is altered, it can lead to uncontrolled cell proliferation and cancer. Selpercatinib works by selectively binding to the RET protein, blocking its activity and thereby hindering the growth and survival of cancer cells. This selective inhibition is crucial because it allows for targeted therapy, minimizing damage to normal, healthy cells and reducing the overall side effects typically associated with more generalized cancer treatments like chemotherapy.

Administering Selpercatinib is straightforward but needs to be carefully managed to ensure its effectiveness and minimize side effects. The drug is available in oral capsule form, making it convenient for patients to take at home. The recommended dosage can vary depending on the specific type of cancer being treated and other individual factors such as patient weight and overall health. Generally, it is taken twice daily, with or without food. The onset time for Selpercatinib can differ among patients, but clinical trials have shown that some individuals experience a reduction in tumor size within a few weeks of starting the treatment. However, it's essential for patients to maintain regular follow-ups with their healthcare providers to monitor their response to the therapy and make any necessary adjustments.

Like all medications, Selpercatinib comes with a range of potential side effects, which can vary in severity from patient to patient. Common side effects include fatigue, dry mouth, diarrhea, and high blood pressure. More serious but less common side effects can include liver toxicity, QT prolongation (a heart rhythm condition), and severe hypertension. Given these risks, it's crucial for patients to undergo regular monitoring, including blood tests and imaging studies, to catch any adverse effects early. Contraindications for using Selpercatinib include known hypersensitivity to the drug or any of its components. Additionally, caution is advised for patients with pre-existing conditions such as severe liver or heart disease. Pregnant or breastfeeding women should also avoid this medication due to potential risks to the fetus or newborn.

Selpercatinib can interact with other medications, which may either reduce its effectiveness or increase the risk of side effects. Some drugs that can affect Selpercatinib include certain antibiotics like rifampin, antifungal medications like ketoconazole, and anticonvulsants like phenytoin. These drugs can either induce or inhibit the enzymes responsible for metabolizing Selpercatinib, thereby altering its levels in the blood. It's also essential for patients to avoid grapefruit and grapefruit juice, as they can interfere with the drug's metabolism. Patients should provide their healthcare providers with a comprehensive list of all medications and supplements they are taking to avoid potential interactions and ensure the best possible outcomes from their Selpercatinib treatment.