Jan 23, 2020: U.S. FDA granted accelerated approval to Tazverik (tazemetostat) for the treatment of adults and pediatric patients aged 16 years and older with metastatic (when cancer cells spread to other parts of the body) or locally advanced (when the cancer has grown outside the organ it started in, but has not yet spread to distant parts of the body) epithelioid sarcoma not eligible for the complete resection (surgically removing all of the tissue, structure, or organ).
Epithelioid sarcoma is a rare sub-type of the soft tissue sarcoma that often occurs in young adults. “Epithelioid sarcoma accounts for less than one percent of all soft tissue sarcomas,”
MOA: Tazverik blocks activity of the EZH2 methyltransferase, which could help keep the cancer cells from growing.
The majority cases of epithelioid sarcoma begin in the soft tissue under the skin of an extremity, although it can start in other areas of the body. Surgical removal is considered the key treatment when the cancer is localized to one area of the body.
Chemotherapy or radiation may also be given. nevertheless, there is a high likelihood for the local and regional spread of the disease even with treatment and around 50% of patients have metastatic disease at the time of diagnosis.
Tazverik’s approval was based on results of a clinical trial enrolling 62 patients with the metastatic or locally advanced epithelioid sarcoma. During this trial, patients received 800 milligrams (mg) of Tazverik two times a day until the disease progressed or the patient reached an intolerable level of toxicity.
Tumor response assessments were performed every eight weeks throughout the clinical trial. The overall response rate of the trial was 15%, with 1.6% of patients having a complete response and 13% having a partial response.
Of the nine patients that had a response, six (67%) patients have a response lasting six months or longer.
Side effects: Patients treated with Tazverik are at increased risk of developing secondary malignancies including: T-cell lymphoblastic lymphoma (a type of blood cancer that affects the lymphatic system generally found in the lymph nodes), myelodysplastic syndrome (a disorder resulting from the poorly formed or dysfunctional blood cells) and the acute myeloid leukemia (a cancer of the blood and bone marrow).
Tazverik granted Accelerated Approval, which enables the FDA in order to approve drugs for the serious conditions to fill an unmet medical need based on a result that is reasonably likely to predict a clinical benefit to patients.
Tazverik also received Orphan Drug designation, which provides incentives to support and encourage the development of drugs for rare diseases.The FDA also granted approval of Tazverik to Epizyme Inc.
