What the label lists and what reports show
Tazemetostat side effects
Tazemetostat's FDA label: “The most common (≥20%) adverse reactions in patients with epithelioid sarcoma are pain, fatigue, nausea, decreased appetite, vomiting, and constipation.” FAERS holds 1,598 reports naming it through July 30, 2026; the reaction reported most often, leaving out the conditions it is used for, product-use terms and outcomes, is fatigue (326 reports).
- No generic listed
- A presentation discontinued
Check it at the source: the tazemetostat FDA label on DailyMed (effective April 29, 2026, Epizyme, Inc.); the FDA FAERS public dashboard.
What does the patient leaflet say about side effects?
From the patient leaflet: What are the possible side effects of TAZVERIK?TAZVERIK can cause serious side effects. See "What is the most important information I should know about TAZVERIK?" The most common side effects of TAZVERIK in people with epithelioid sarcoma include: pain nausea vomiting tiredness decreased appetite constipation The most common side effects of TAZVERIK in people with follicular lymphoma include: tiredness bone and muscle pain cold-like symptoms (upper respiratory infection) nausea stomach (abdominal) pain These are not all the possible side effects of TAZVERIK. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
Source: FDA drug label, Epizyme, Inc., effective April 29, 2026 (SPL set 7db07b5f-4e22-467c-9c0a-f830b08dbb1d), via openFDA; the full label on DailyMed
What does the label list?
From the label: adverse reactionsThe most common (≥20%) adverse reactions in patients with epithelioid sarcoma are pain, fatigue, nausea, decreased appetite, vomiting, and constipation.
Table 6. Adverse Reactions (≥10%) in Patients with Relapsed or Refractory Follicular Lymphoma Who Received TAZVERIK in Cohorts 4 and 5 of Study E7438-G000-101
| Reaction | Adverse Reaction All Grades (%) | TAZVERIK N=99 Grade 3 or 4 (%) |
|---|---|---|
| Fatigue a | 36 | 5 |
| Pyrexia | 10 | 0 |
| Upper respiratory tract infection b | 30 | 0 |
| Lower respiratory tract infection c | 17 | 0 |
| Urinary tract infection d | 11 | 2 |
| Nausea | 24 | 1 |
| Abdominal pain e | 20 | 3 |
| Diarrhea | 18 | 0 |
| Vomiting | 12 | 1 |
| Musculoskeletal pain f | 22 | 1 |
| Alopecia | 17 | 0 |
| Rash g | 15 | 0 |
| Cough h | 17 | 0 |
| Headache i | 13 | 0 |
Rows and numbers as the label prints them, under its own column headings (the first rows of a longer table where it runs on). A reaction in a trial table is not necessarily caused by the medicine, and trials differ from everyday use.
From the label: adverse reactions, continuedThe following clinically significant adverse reactions are described elsewhere in labeling: Secondary Malignancies [see Warnings and Precautions ( 5.1 )]. The most common (≥20%) adverse reactions in patients with epithelioid sarcoma are pain, fatigue, nausea, decreased appetite, vomiting, and constipation. ( 6.1 ) The most common (≥20%) adverse reactions in patients with follicular lymphoma are fatigue, upper respiratory tract infection, musculoskeletal pain, nausea, and abdominal pain. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Epizyme at 855-463-5127 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Trial Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared with rates in the clinical trials of another drug and may not reflect the rates observed in practice. Epithelioid Sarcoma The safety of TAZVERIK was evaluated in a cohort (Cohort 5) of Study EZH-202 that enrolled patients with epithelioid sarcoma [see Clinical Studies ( 14.1 )]. Patients received TAZVERIK 800 mg orally twice daily (n=62). Among patients who received TAZVERIK, 44% were exposed for 6 months or longer and 24% were exposed for greater than one year. Serious adverse reactions occurred in 37% of patients who received TAZVERIK. …
Source: FDA drug label, Epizyme, Inc., effective April 29, 2026 (SPL set 7db07b5f-4e22-467c-9c0a-f830b08dbb1d), via openFDA; the full label on DailyMed
What do FAERS reports show?
1,598 reports list tazemetostat among the medicines taken, each a report of something that happened, not proof the medicine caused it; 209 are coded as a death and 322 as a hospital stay. Counts follow how widely a medicine is used and watched, and they are not a measure of how risky it is. Of the 20 reactions below, 15 are named by the same term (in US spelling) in the label's adverse reactions, warnings or patient leaflet; a reaction the label does not name may still be there under another word, and a report does not show that the medicine caused it.
Reports received each year
The 25 most reported reactions
Source: FDA Adverse Event Reporting System (FAERS) via openFDA, reports through July 30, 2026; reactions as MedDRA preferred terms
What next?
- Tazemetostat: the full record
- label, generics, price, shortages, recalls
- Report a side effect to the FDA
- MedWatch
- Side effects hub
- the most reported medicines and reactions