Ipsen Withdraws Tazemetostat Across Approved Indications Following SYMPHONY-1 Safety Review

Clinical Summary: 

• Tazemetostat has been voluntarily withdrawn from the market after emerging safety findings from the confirmatory phase 1b/3 SYMPHONY-1 trial raised concerns regarding secondary hematologic malignancies.

• The Independent Data Monitoring Committee determined that the risk-benefit profile of the tazemetostat-containing regimen was no longer favorable. Ipsen has discontinued treatment in ongoing studies, halted all active clinical trials and expanded access programs, and initiated withdrawal procedures with global regulatory authorities.

• This withdrawal underscores the importance of confirmatory trials conducted under the FDA's accelerated approval pathway to verify long-term clinical benefit and safety.

Ipsen has announced the voluntary withdrawal of tazemetostat (Tazverik) from all approved indications following emerging safety findings from the ongoing phase 1b/3 SYMPHONY-1 trial.

The decision follows a recommendation from the Independent Data Monitoring Committee, which concluded that an increased incidence of secondary hematologic malignancies observed in the tazemetostat-containing treatment arm resulted in an unfavorable risk-benefit profile.

SYMPHONY-1 is a global phase 1b/3 confirmatory trial evaluating tazemetostat in combination with lenalidomide and rituximab as second-line treatment for patients with relapsed or refractory follicular lymphoma. The study was being conducted to confirm the clinical benefit supporting the FDA's accelerated approval of tazemetostat in follicular lymphoma.

Effective immediately, Ipsen has discontinued tazemetostat treatment in all ongoing clinical trials and expanded access programs worldwide. Patients enrolled in SYMPHONY-1 will discontinue tazemetostat and transition to standard-of-care treatment with lenalidomide plus rituximab. Although enrollment has ceased, the study will continue to collect long-term safety data.

The company is also working with the US Food and Drug Administration (FDA) and other global regulatory authorities to complete the withdrawal process.

Tazemetostat received FDA accelerated approval in 2020 for adults with relapsed or refractory follicular lymphoma harboring an EZH2 mutation after at least two prior systemic therapies, as well as for patients with relapsed or refractory follicular lymphoma who had no satisfactory alternative treatment options. The drug also received accelerated approval in 2020 for adults and adolescents aged 16 years and older with metastatic or locally advanced epithelioid sarcoma not eligible for complete surgical resection.

Both approvals were granted under the accelerated approval pathway based on objective response rate and duration of response and were contingent upon confirmation of clinical benefit in postmarketing studies.

Ipsen stated that patient safety remains its highest priority and that it is working with investigators, treating physicians, and regulatory agencies to support patients affected by the withdrawal.

Source: 

Ipsen. Ipsen voluntarily withdraws Tazverik® (tazemetostat) in follicular lymphoma and epithelioid sarcoma. Accessed on March 11, 2026. https://www.ipsen.com/press-release/ipsen-voluntarily-withdraws-tazverik-tazemetostat-in-follicular-lymphoma-and-epithelioid-sarcoma-3251503/