Cancer Drug Withdrawal Raises Safety Concerns for Lymphoma Patients
New data linking tazemetostat to secondary blood cancers prompts global market withdrawal and trial discontinuation
A cancer drug used to treat certain lymphomas and sarcomas is being withdrawn worldwide after new trial data suggested a possible increased risk of secondary blood cancers. The decision highlights how accelerated approvals depend on confirmatory studies to verify long-term safety and benefit.
Study Details
Tazemetostat, marketed as Tazverik, is an oral cancer drug that targets EZH2, an enzyme involved in gene regulation and tumor growth. The therapy received accelerated approval from the U.S. Food and Drug Administration in 2020 for two groups of patients:
• Individuals with follicular lymphoma whose tumors carry an EZH2 mutation and who had already received prior treatments.
• Patients with metastatic or locally advanced epithelioid sarcoma who were not candidates for complete surgical removal.
Accelerated approvals allow promising drugs to reach patients sooner, particularly when treatment options are limited. However, companies must later conduct confirmatory trials to demonstrate that the drug truly improves patient outcomes and maintains an acceptable safety profile.
The new safety concerns emerged during one such trial called SYMPHONY-1, which evaluated tazemetostat as part of a combination treatment for follicular lymphoma.
Methodology
SYMPHONY-1 was a large international phase Ib/III clinical study conducted across 229 research sites in 15 countries, including the United States, Europe, and China.
Researchers evaluated whether adding tazemetostat to a standard treatment regimen could improve outcomes in follicular lymphoma.
Participants received:
• Lenalidomide plus rituximab, a widely used therapy for this cancer
• Or the same combination with the addition of tazemetostat
An independent data monitoring committee periodically reviewed safety data as the study progressed.
During these reviews, investigators observed a pattern of secondary hematologic malignancies, meaning new blood cancers developing after treatment. The committee concluded that the safety risks might outweigh the potential benefits of including tazemetostat in the regimen.
Following this assessment, the manufacturer Ipsen decided to withdraw the drug from the market and stop all active clinical trials and expanded access programs.
Key Findings
• A confirmatory clinical trial identified increased rates of secondary blood cancers among patients receiving tazemetostat in combination therapy.
• Independent safety reviewers concluded that the risks may outweigh the benefits in follicular lymphoma treatment.
• The manufacturer voluntarily decided to withdraw the drug globally and discontinue ongoing trials.
• The SYMPHONY-1 study will remain open only to monitor long-term safety outcomes among participants.
• Patients in the trial will now receive standard therapy with lenalidomide and rituximab without tazemetostat.
Implications for Practice
For patients and clinicians, the withdrawal of tazemetostat highlights the importance of long-term safety monitoring in cancer therapies approved under accelerated pathways.
While accelerated approvals can provide earlier access to innovative treatments, they also rely heavily on follow-up studies to confirm that benefits outweigh risks. When those studies reveal safety concerns, regulators and manufacturers may need to reassess the therapy’s place in treatment.
For physicians treating follicular lymphoma or epithelioid sarcoma, the withdrawal means that patients currently receiving tazemetostat will likely need to transition to other therapies. Established regimens such as lenalidomide combined with rituximab remain important treatment options.
More broadly, the decision underscores a pattern seen with several oncology drugs in recent years. Some medications initially approved on early trial data have later been removed after confirmatory trials failed to demonstrate sufficient benefit or revealed new safety signals.
For patients, these developments may feel unsettling, but they also illustrate how continuous clinical research and safety monitoring protect patients over time.