Tazemetostat, sold under the brand name Tazverik, is a medication used for the treatment of adults and adolescents aged 16 years and older with metastatic (when cancer cells spread to other parts of the body) or locally advanced (when 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 complete resection (surgically removing all of a tissue, structure, or organ).The most common side effects are pain, fatigue, nausea, decreased appetite, vomiting and constipation. People taking tazemetostat are at increased risk of developing secondary malignancies including: T-cell lymphoblastic lymphoma (a type of blood cancer that affects the lymphatic system usually found in the lymph nodes), myelodysplastic syndrome (a disorder resulting from poorly formed or dysfunctional blood cells) and acute myeloid leukemia (a cancer of the blood and bone marrow).Tazemetostat is a cancer drug that acts as a potent selective EZH2 inhibitor. 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.
Despite the use of supportive care, an estimated 33–40% of patients will die or have end-stage renal disease (ESRD) with the first clinical manifestation of aHUS, and 65% of patients will die, require dialysis, or have permanent renal damage within the first year after diagnosis despite plasma exchange or plasma infusion (PE/PI) therapy. Patients who survive the presenting signs and symptoms of aHUS endure a chronic thrombotic and inflammatory state, which puts them at lifelong elevated risk of sudden blood clotting, kidney  failure, other severe complications and premature death.Historically, treatment options for aHUS were limited to plasma exchange or plasma infusion (PE/PI) therapy, which carries significant risks and has not been proven effective in any controlled trials. People with aHUS and ESRD have also had to undergo lifelong dialysis, which has a 5-year survival rate of 34–38%. Pathogenesis
HUS is one of the thrombotic microangiopathies, a category of disorders that includes STEC-HUS, aHUS, and thrombotic thrombocytopenic purpura (TTP). STEC-HUS occurs after ingestion of a strain of bacteria expressing Shiga toxin(s), usually types of E. coli, that expresses verotoxin (also called Shiga-like toxin). E. coli can produce stx1 and/or stx2 Shiga toxins, the latter being more dangerous. A combination of both toxins in certain ratios is usually associated with HUS. These Shiga toxins bind GB3 receptors, globotriaosylceramide, which are present in renal tissue more than any other tissue and are also found in central nervous system neurons and other tissue. Children have more GB3 receptors than adults which may be why children are more susceptible to HUS.