The U.S. Food and Drug Administration ) FDA ) has granted accelerated approval to Tazverik ( Tazemetostat ) for the treatment of adults and pediatric patients aged 16 years and older with metastatic or locally advanced epithelioid sarcoma not eligible for complete resection ( surgically removing all of a tissue, structure, or organ ).
Epithelioid sarcoma is a rare sub-type of soft tissue sarcoma that often occurs in young adults.
Tazemetostat blocks activity of the EZH2 methyltransferase, which may help keep the cancer cells from growing.
Most cases of epithelioid sarcoma begin in the soft tissue under the skin of an extremity, though it can start in other areas of the body.
Surgical removal is considered the main treatment when the cancer is localized to one area of the body. Chemotherapy or radiation may also be given. However, there is a high likelihood for local and regional spread of the disease even with treatment and approximately 50% of patients have metastatic disease at the time of diagnosis. Metastatic disease is considered life-threatening to the patient.
Tazverik’s approval was based on the results of a clinical trial enrolling 62 patients with metastatic or locally advanced epithelioid sarcoma.
During the clinical trial, patients received 800 milligrams ( mg ) of Tazverik twice a day until the disease progressed or the patient reached an unacceptable level of toxicity.
Tumor response assessments were performed every eight weeks during the clinical trial. The trial measured how many patients experienced complete or partial shrinkage of their tumors during treatment ( overall response rate; ORR ).
The overall response rate was 15%, with 1.6% of patients having a complete response ( CR ) and 13% having a partial response ( PR ). Of the nine patients that had a response, six ( 67% ) patients had a response lasting six months or longer.
The most common side effects for patients taking Tazverik were: pain, fatigue, nausea, decreased appetite, vomiting and constipation.
Patients treated with Tazverik are at increased risk of developing secondary malignancies including: T-cell lymphoblastic lymphoma, myelodysplastic syndrome and acute myeloid leukemia.
The FDA has advised health care professionals to tell females of reproductive potential to use effective contraception during treatment with Tazverik and for six months after the final dose. Males with a female partner of reproductive potential should use effective contraception during treatment with Tazverik and for three months after the final dose.
Females who are pregnant or breastfeeding should not take Tazverik because it may cause harm to a developing fetus or newborn baby.
Tazverik must be dispensed with a patient Medication Guide that describes important information about the drug’s uses and risks. ( Xagena )
Source: FDA, 2020