FDA Alerts Health Care Providers and Patients About Increased Risk of New Blood Cancers with Tazverik (Tazemetostat) Use; Sponsor to Voluntarily Withdraw Product From Market

Why It Matters

The withdrawal underscores heightened regulatory vigilance for post‑approval safety signals, especially for oncology drugs granted accelerated approval, and leaves a treatment gap for rare sarcoma and lymphoma patients.

Key Takeaways

• SYMPHONY‑1 trial found 5.7% hematologic SPMs vs 0% control
• Most SPMs were MDS or AML, causing three deaths
• Withdrawal impacts epithelioid sarcoma and follicular lymphoma patients
• Ipsen will halt U.S. sales and all expanded‑access programs
• FDA urges providers to report adverse events through MedWatch

Pulse Analysis

Tazverik, an EZH2 inhibitor, entered the U.S. market in 2020 under the FDA’s accelerated approval pathway, targeting rare cancers such as metastatic epithelioid sarcoma and relapsed follicular lymphoma. While the drug offered a novel mechanism for patients with limited options, its approval came with a known, albeit low, risk of second primary malignancies—initially reported at 1.7%. The accelerated route allowed earlier access but relied heavily on post‑marketing data to confirm safety and efficacy.

The pivotal SYMPHONY‑1 trial, designed to evaluate Tazverik in combination with lenalidomide and rituximab, revealed a stark safety signal: 18 of 318 patients (5.7%) developed serious hematologic SPMs, primarily myelodysplastic syndrome and acute myeloid leukemia, with three fatalities. The events emerged after 7.5 months of therapy and persisted even after treatment cessation, prompting an independent data monitoring committee to halt enrollment and recommend immediate discontinuation. In response, sponsor Ipsen elected to withdraw Tazverik from the U.S. market and terminate all expanded‑access programs, signaling that the risk‑benefit calculus could no longer justify continued use.

The episode highlights a broader trend of intensified scrutiny for drugs granted accelerated approval, especially in oncology where long‑term safety data may lag behind market entry. Regulators are reinforcing the need for robust post‑marketing surveillance, and manufacturers must be prepared for rapid corrective actions when adverse signals emerge. For clinicians, the withdrawal creates a therapeutic void for patients with epithelioid sarcoma and follicular lymphoma, accelerating the search for alternative agents and underscoring the importance of vigilant adverse‑event reporting through FDA MedWatch.