FDA Issues Additional Tazverik Blood Cancer Warnings After Market Recall

More than 5% of patients developed a secondary form of blood cancer during treatment with Tazverik, which was removed from the market in March.

Despite its removal from the market in March, federal regulators are issuing new warnings urging doctors not to give patients the lymphoma drug Tazverik due to a higher-than-expected risk of blood cancers.

Tazverik (tazemetostat) was approved by the U.S. Food and Drug Administration (FDA) in 2020 for certain patients with metastatic or locally advanced epithelioid sarcoma and follicular lymphoma. The approval was based on a single-arm clinical trial, meaning the drug’s effectiveness was evaluated without being compared against another treatment.

The medication was designed to slow cancer progression by inhibiting enzymes involved in tumor growth when they become mutated or overactive. However, concerns have since emerged about serious long-term risks, including secondary blood cancers.

On March 8, the drug’s manufacturer, Ipsen, announced that it was removing Tazverik from the market due to the high rate of these secondary cancers. Although the recall is already underway, the FDA has also warned health care providers and patients that the risks of Tazverik now outweigh any potential benefits, urging that any remaining supply not be given to patients.

Tazverik Blood Cancer Risks

According to the FDA press release issued on May 11, the clinical trial indicated that Tazverik carried a blood cancer incidence rate of just 1.7%, but the agency is now warning that the rate appears to be more than 5%, with a mean duration of 15.8 months.

The new rates were discovered during the ongoing SYMPHONY-1 clinical trial, which was evaluating Tazverik in combination with the immunotherapy drugs lenalidomide (Revlimid) and rituximab (Rituxan) for patients with relapsed or refractory follicular lymphoma. The study was designed to serve as the confirmatory trial required under the FDA’s accelerated approval pathway.

The agency’s warning noted that, as of March 6, at least 18 out of 318 patients, or 5.7%, or those treated with Tazverik developed second primary malignancies (SPMs), all of which were forms of blood cancer. No patients developed these cancers in the control arm of the SYMPHONY-1 clinical trial, the agency notes.

“Most participants who developed the new blood cancers were receiving Tazverik for 1-3 years. The SPMs started as early as 7.5 months after beginning treatment and occurred in some patients after stopping treatment.”

– U.S. Food and Drug Administration press release

According to Ipsen, the problems were first identified by the clinical trial’s Independent Data Monitoring Committee (DMC). The DMC evaluates patient safety during clinical trials and concluded that Tazverik safety risks were not worth its limited health benefits.

The FDA supported the DMC’s recommendations that enrollment in SYMPHONY-1 end immediately, and that all patients taking Tazverik should discontinue use immediately. The agency indicates that the study will remain active to monitor long-term safety risks for patients who have already used Tazverik, while all expanded access programs for the medication will be discontinued.

Federal regulators are urging health care providers and patients to report any Tazverik side effects to the FDA’s MedWatch adverse event reporting program.

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