FDA lifts partial clinical hold on tazemetostat trials

The FDA lifted a partial clinical hold it had placed on clinical trials designed to evaluate tazemetostat, according to the drug’s manufacturer.

Tazemetostat (Epizyme) is a first-in-class EZH2 inhibitor.

Phase 1 and phase 2 trials were designed to evaluate the agent for patients with molecularly defined solid tumors — including epithelioid sarcoma — and hematologic malignancies, including follicular lymphoma, diffuse large B-cell lymphoma, mesothelioma and non-small cell lung cancer.

The FDA ordered the partial clinical hold in April, placing a temporary halt on U.S.-based enrollment of new patients into tazemetostat trials.

The agency based the decision on a safety report of a pediatric patient enrolled in a tazemetostat trial who developed a secondary lymphoma.

The patient had advanced poorly differentiated chordoma and was being treated in a phase 1 pediatric study of tazemetostat.

At the time of the safety report, the patient had been on study for about 15 months and had achieved a confirmed partial response.

In response to the FDA’s decision, Epizyme submitted a comprehensive assessment of the risk of secondary malignancies, including T-cell lymphoblastic lymphoma (T-LBL) potentially associated with tazemetostat.

The company also provided “a thorough assessment of efficacy and safety data across all of its trials” designed to evaluate tazemetostat for adults or children with solid tumors or hematologic malignancies, according to an Epizyme-issued press release.

The company also convened a panel of external medical and scientific experts to review and validate the findings.

“The Epizyme team has worked diligently to provide a comprehensive response back to the FDA and, through constructive dialogue, we successfully resolved the partial clinical hold,” Robert Bazemore, president and CEO of Epizyme, said in the release. “This allows us to turn our full attention to our key priorities: preparing for our first new drug application submission for tazemetostat in epithelioid sarcoma and defining our registration path in follicular lymphoma.

“We, along with our investigators and the global experts we consulted to support our complete response, continue to believe in the positive benefit/risk of tazemetostat as we move forward in our clinical development program,” Bazemore added. “We remain steadfast in our commitment to bringing this potential therapeutic option to [patients with cancer] in need of safe and effective new treatments.”

Company officials indicated they will work with regulatory authorities in Germany and France to resolve partial clinical holds that halted trial enrollment in those countries.