Selinexor

Introduction: What is Selinexor?

Selinexor is a medication primarily used in the treatment of certain types of cancer, particularly multiple myeloma and diffuse large B-cell lymphoma (DLBCL). It is classified as a selective inhibitor of nuclear export (SINE) and works by blocking the export of tumor suppressor proteins from the nucleus of the cell, thereby promoting cancer cell death. Approved by the FDA in 2019, Selinexor represents a novel approach to cancer therapy, especially for patients who have not responded to other treatments.

Uses of Selinexor

Selinexor is approved for the following medical uses:

• Multiple Myeloma: It is used in combination with dexamethasone and bortezomib for patients who have received at least one prior proteasome inhibitor and at least two prior immunomodulatory agents.
• Diffuse Large B-cell Lymphoma (DLBCL): As monotherapy for patients with relapsed or refractory DLBCL, not otherwise specified, after at least two prior systemic therapies.

How Does It Work?

Selinexor works by inhibiting a protein called exportin 1 (XPO1), which is responsible for transporting certain proteins out of the cell nucleus. In cancer cells, this transport often includes tumor suppressor proteins that help control cell growth and division. By blocking XPO1, Selinexor allows these tumor suppressor proteins to accumulate in the nucleus, leading to increased cancer cell death and reduced tumor growth. In simpler terms, it helps the body?s natural defenses against cancer work more effectively.

Dosage and Administration

Selinexor is typically administered as an oral tablet. The standard dosage for adults with multiple myeloma is 80 mg once weekly on day 1 of each 7-day cycle (with dexamethasone and bortezomib if applicable), while for DLBCL, it is usually 60 mg twice weekly on days 1 and 3 of each 7-day cycle. Dosage may vary based on individual patient factors, including weight, overall health, and response to treatment. It is crucial to follow the prescribing physician's instructions regarding dosage and administration frequency.

Side Effects of Selinexor

Common side effects of Selinexor include:

• Nausea
• Vomiting
• Diarrhea
• Fatigue
• Loss of appetite
• Weight loss
• Low blood cell counts (anemia, neutropenia, thrombocytopenia)
• Hyponatremia

Serious side effects may include:

• Severe allergic reactions
• Liver problems (elevated liver enzymes)
• Blood clots
• Neurological effects (confusion, seizures)
• Hyponatremia (often causes confusion/seizures)
• Myelosuppression
• Severe gastrointestinal toxicity

Patients should report any severe or persistent side effects to their healthcare provider immediately.

Drug Interactions

Selinexor can interact with several medications, which may affect its efficacy or increase the risk of side effects. Major drug interactions include:

• Strong CYP3A4 inhibitors: (e.g., ketoconazole, ritonavir)
• Strong CYP3A4 inducers: (e.g., rifampin, St. John?s Wort)
• Anticoagulants: (e.g., warfarin)
• Proteasome inhibitors, immunomodulators, or other myelosuppressive agents

Note: Primary metabolism via non-CYP pathways; emphasize P-gp substrates and avoid strong inducers.

It is essential for patients to inform their healthcare provider about all medications, supplements, and herbal products they are taking.

Benefits of Selinexor

The clinical advantages of using Selinexor include:

• Novel Mechanism: As a SINE, it offers a unique approach to cancer treatment, particularly for resistant cases.
• Oral Administration: The convenience of taking a pill rather than undergoing injections or infusions.
• Potential for Combination Therapy: Selinexor can be used alongside other cancer treatments, enhancing overall effectiveness.

Contraindications of Selinexor

Certain individuals should avoid using Selinexor, including:

• Pregnant or breastfeeding women: due to potential harm to the fetus or infant (contraindicated; Pregnancy Category Not Assigned, REMS program required).
• Patients with severe liver disease: as the drug is metabolized in the liver and may exacerbate liver function.
• Individuals with a known hypersensitivity: to Selinexor or any of its components.

Precautions and Warnings

Before starting Selinexor, patients should undergo specific lab tests to monitor liver function and blood cell counts. It is crucial to discuss any preexisting health conditions with a healthcare provider, especially liver issues, blood disorders, or a history of blood clots. Regular follow-up appointments are necessary to assess treatment response and manage side effects. Dose modifications required for thrombocytopenia, neutropenia, hyponatremia; antiemetics required prophylactically. Embryo-fetal toxicity risk requires contraception.

FAQs

• What is Selinexor used for? Selinexor is used to treat multiple myeloma (in combination with dexamethasone and bortezomib after at least one prior PI and two IMiDs) and relapsed/refractory DLBCL (monotherapy after ?2 prior therapies).
• How is Selinexor taken? Selinexor is taken orally in tablet form, usually once or twice a week, depending on the condition being treated.
• What are the common side effects? Common side effects include nausea, vomiting, diarrhea, fatigue, and low blood cell counts.
• Can Selinexor be taken with other medications? Yes, but it is essential to inform your doctor about all the medications you are taking to avoid interactions.
• Is Selinexor safe during pregnancy? No, Selinexor is contraindicated in pregnancy due to potential risks to the fetus.
• How does Selinexor work? It inhibits the export of tumor suppressor proteins from the cell nucleus, promoting cancer cell death.
• What should I do if I miss a dose? If you miss a dose, take it as soon as you remember unless it?s close to the time of your next dose. Do not double up.
• Are there any serious side effects? Yes, serious side effects can include severe allergic reactions, liver problems, and blood clots.
• How often will I need to see my doctor while on Selinexor? Regular follow-up appointments are necessary to monitor your response to treatment and manage side effects.
• Can I drink alcohol while taking Selinexor? Avoid alcohol, as it may worsen nausea, dehydration, or hepatotoxicity.

Brand Names

Selinexor is marketed under the brand name Xpovio.

Conclusion

Selinexor represents a significant advancement in the treatment of multiple myeloma and diffuse large B-cell lymphoma, particularly for patients who have exhausted other treatment options. Its unique mechanism of action, combined with the convenience of oral administration, makes it a valuable addition to cancer therapy. However, as with any medication, it is essential to discuss potential side effects, interactions, and individual health considerations with a healthcare provider.