Last year, the anticancer drug Tazverik (tazemetostat) received approval for use in the treatment of 2 malignancies. First, it was approved by the Food and Drug Administration (FDA) for the treatment of adults and young patients 16 years of age or older with epithelioid sarcoma. This approval applies to patients who have locally advanced cancer (the cancer has grown outside the body part it started in but has not yet spread to other parts of the body) or metastatic cancer (the cancer has spread to other parts of the body), and whose tumors cannot be removed by surgery. This is the first treatment to be approved by the FDA specifically for the treatment of patients with epithelioid sarcoma. Later in 2020, the FDA approved Tazverik for the treatment of adults with follicular lymphoma (FL) when the disease has come back or did not respond to previous treatment, whose tumors have an abnormal EZH2 gene, and who have been treated with at least 2 prior medicines. Further, Tazverik is used to treat adults with FL when the disease has come back or did not respond to treatment, and who have no other satisfactory treatment option.
Richard Pazdur, MD, director of the FDA’s Oncology Center of Excellence, commented on the approval of Tazverik for epithelioid sarcoma, saying: “Epithelioid sarcoma accounts for less than 1 percent of all soft tissue sarcomas. Until today, there were no treatment options specifically for patients with epithelioid sarcoma. The approval of Tazverik provides a treatment option that specifically targets this disease. When we brought Tazverik’s application to the Oncologic Drugs Advisory Committee last month, the committee voted unanimously that the benefits of the drug outweighed the risks.”
What Is Epithelioid Sarcoma?
Epithelioid sarcoma is a rare type of sarcoma that most often occurs in the soft tissue of the fingers, hands, and forearms (but it can occur in other areas of the body).
This type of cancer typically affects young adults (but it can occur at any age), and it is more common in men than in women. It can be challenging to diagnose due to its slow tumor growth and often benign (not cancerous) categorization when it is in the early stages of the disease.
Epithelioid sarcoma tends to come back often after initial therapy and to spread to other parts of the body (like the lungs), usually through the lymphatic system. The standard treatment for this type of cancer is surgical removal of the tumor and the tissue surrounding it, but in some cases chemotherapy and radiation are used. However, the recent approval of Tazverik offers new hope for patients who are not candidates for surgery.
What Is FL?
FL is a type of blood cancer that occurs when certain white blood cells, called B lymphocytes, grow and multiply uncontrollably. These cancerous lymphocytes can travel to different parts of the body, such as the lymph nodes, spleen, bone marrow, and other organs. Although FL typically grows and spreads slowly, most people will eventually have progressive FL that requires multiple treatments over time. FL belongs to a broader group of cancers affecting the B lymphocytes called non-Hodgkin lymphomas, or NHL.
Taking Tazverik—Looking Out for Side Effects
Patients should take Tazverik exactly as their doctor instructs them, but the recommended dose is 800 mg given by mouth twice a day. Tablets can be taken with or without food, but they should be swallowed whole and should not be cut, crushed, or chewed. If a dose is missed, or if taking the medicine leads to vomiting, just skip that dose and take the next dose at the regularly scheduled time. If certain side effects happen, the dose may need to be changed or temporarily stopped, and treatment may need to be stopped completely if side effects are serious enough.
The most common side effects of Tazverik (occurring in at least 20% of patients) are pain, tiredness, nausea, decreased appetite, vomiting, and constipation. However, it is important to note that these are not all of the possible side effects of this treatment, and patients using this drug should call their doctor with any and all concerns.
Treatment with this drug can increase the risk for new (second) cancers, including T-cell lymphoblastic lymphoma, myelodysplastic syndrome, and acute myeloid leukemia, so patients receiving Tazverik should be monitored regularly for second cancers and should tell their doctor immediately if they are feeling more tired than usual, if they are bruising easily, or if they are experiencing fever, bone pain, or paleness.
Patients should not consume food or drinks containing grapefruit when taking this drug because grapefruit is considered a CYP3A inhibitor and may increase the risk of side effects. Other drugs that are strong inhibitors of CYP3A (like clarithromycin or erythromycin) may also increase the risk of side effects with Tazverik and should be avoided. Strong or moderate CYP3A inducers (like rifampicin or St. John’s wort) may make the drug less effective, so these should also be avoided while on treatment. Giving this drug with hormonal contraceptives (birth control pills) and other hormonal forms of birth control may make the birth control less effective, so backup nonhormonal birth control (such as condoms) should be used while on treatment with Tazverik. Patients should talk with their healthcare provider about available birth control options.
Before taking Tazverik, patients should tell their doctor about any medical conditions, including if they are pregnant or plan to become pregnant. Women who are pregnant or plan to become pregnant should not take this drug because it can cause harm to an unborn baby or result in a miscarriage. Women who can become pregnant should always use effective nonhormonal birth control when taking this drug, and for 6 months after the final dose. Men with female partners who are able to become pregnant should also use effective birth control during treatment, and for 3 months after the final dose. It is not yet known whether Tazverik passes into human breast milk (and if it does, whether it would harm a baby), so women should not breastfeed during treatment and for 1 week after their final dose.
Patients should also tell their healthcare provider about any prescription and over-the-counter medicines they take, including vitamins and herbal supplements. This is because Tazverik may affect the way other medicines work, and other medicines may affect how Tazverik works.
Tavzerik is the first and only FDA-approved EZH2 inhibitor with meaningful clinical benefit in patients with metastatic or locally advanced epithelioid sarcoma. This drug is a game changer in this rare malignancy. Also notable is Tazverik’s approval for use in patients with relapsed or refractory follicular lymphoma after having received at least 2 previous therapies and whose tumors are positive for an EZH2 mutation—again, this is the first and only FDA-approved EZH2 inhibitor indicated for these patients.