FDA approves first extended release injection to treat osteoarthritis knee pain

Michael Clayman

The FDA approved triamcinolone acetonide intra-articular injection for the treatment of patients with osteoarthritis knee pain, according to the drug’s manufacturer.

Triamcinolone acetonide (Zilretta, Flexion Therapeutics), the first and only extended-release formulation, is a nonopioid medicine that employs proprietary microsphere technology designed to combine triamcinolone acetonide with a poly lactic-co-glycolic acid matrix to provide extended pain relief over 12 weeks.

“The approval of Zilretta marks a major advancement in the treatment landscape for managing osteoarthritis knee pain,” Michael Clayman, MD, president and CEO of Flexion, said in a company-issued release. “It comes at a time when our society is in urgent need of nonaddictive therapies to help the millions of Americans who suffer from this condition. We believe that Zilretta has the potential to be a transformative medicine for the more than five million patients who receive an intra-articular injection for osteoarthritis knee pain each year.”

The agency based its approval on data from the randomized, double-blind phase 3 trials designed to evaluate triamcinolone acetonide in 484 patients with osteoarthritis knee pain.

The drug’s label also included positive data from the double-blind, randomized, parallel-group trial designed to examine blood glucose concentrations in patients with type 2 diabetes.

“Our trial demonstrated that Zilretta may avoid the disruptive blood glucose spikes that can be seen with corticosteroid use in patients coping with both knee osteoarthritis and type 2 diabetes,” Steven Russell, MD, PhD, assistant professor of medicine at Massachusetts General Hospital Diabetes Research Center, said in the release. “As a practicing diabetologist, I believe the availability of Zilretta will make intra-articular injection of glucocorticoid an attractive option for these patients.”