Zilretta Label Update Clears Up Repeated Use Confusion

After granting approval to Flexion Therapeutics, Inc.’s Zilretta in October 2017, the FDA has now given the company permission to revise the Zilretta product label.

Zilretta (triamcinolone acetonide extended-release injectable suspension) is a non-opioid drug for managing chronic osteoarthritis (OA) knee pain.

The previous label said Zilretta was “not intended for repeat administration.” The new label states, “the efficacy and safety of repeat administration” of the drug “have not been demonstrated.”

Other label revisions announced by the company in a December 26, 2019 press release, included:

• inclusion of a study description and safety data from a single-arm, open-label Phase 3 repeat administration trial;
• removal of a “misleading” statement describing a single secondary exploratory endpoint in the original Phase 3 pivotal trial which compared Zilretta to immediate release triamcinolone acetonide crystalline suspension; and,
• inclusion of nonclinical toxicology data from previously submitted single and repeat administration studies in non-diseased animals.

According to the company, the pivotal trial showed that Zilretta “significantly reduced knee pain for 12 weeks, with some people experiencing pain relief through Week 16.”

Company President and CEO Michael Clayman, M.D. said the old label was potentially confusing to patients, physicians and payers. He added the new label “achieves our primary goal of removing unclear language pertaining to repeat administration.”

He said he believes the updated label supports the company’s goal of seeing Zilretta become “the leading intra-articular therapy for managing OA knee pain.”

John Richmond, M.D., Medical Director for Network Development, New England Baptist Hospital, a clinician and Zilretta patient, says he has firsthand experience with the “significant magnitude and duration of pain relief” the treatment can provide to people confronting knee OA. “Zilretta is an invaluable non-opioid option for managing chronic OA knee pain, and it is encouraging to see a new product label that better informs clinical decision making.”

Zilretta was the first and only extended-release intra-articular therapy for patients with OA-related knee pain. According to the company, the drug employs “proprietary microsphere technology combining triamcinolone acetonide—a commonly administered, short-acting corticosteroid—with a poly lactic-co-glycolic acid (PLGA) matrix to provide extended pain relief.”