Flexion Submits NDA for Zilretta

Flexion Therapeutics, Inc. has announced it has submitted a new drug application (NDA) to the FDA for its lead investigational product candidate Zilretta (also known as FX006), meant to treat patients with osteoarthritis (OA) of the knee. According to the December 12, 2016 news release, Zilretta has received Fast Track designation from the FDA, meaning that it is a drug intended to treat a serious condition with the potential to provide meaningful improvement over existing therapies. The FDA has up to 74 days to inform Flexion if the submission has been deemed complete and permits a full review.

“The submission of our first NDA is a major milestone for Flexion Therapeutics. Based on our pivotal data, we believe that Zilretta has the potential to be the first intra-articular, extended-release treatment for the many millions of patients who suffer with knee OA, ” said President and CEO Michael Clayman, M.D., “I am grateful to our dedicated employees, clinical collaborators and board of directors for their commitment to advancing novel therapeutics that address unmet medical needs for patients with musculoskeletal conditions.”

As indicated in the news release, “The Zilretta NDA for OA of the knee is supported by previously reported results from a pivotal Phase 3 clinical trial. The randomized, double blind, placebo and active-comparator (immediate-release triamcinolone acetonide (TA)) controlled trial enrolled 484 patients at 37 centers worldwide. Data from the trial showed that Zilretta demonstrated a highly significant (p<0.0001) reduction in average daily pain versus placebo at week 12 (primary endpoint), with durable and clinically meaningful pain relief in patients with moderate to severe OA knee pain. In addition, compared to immediate-release TA, the most commonly injected intra-articular corticosteroid, Zilretta achieved statistical significance through 12 weeks on WOMAC A (pain), WOMAC B (stiffness) and WOMAC C (function)…”

Dr. Clayman told OTW, “Flexion is in an exciting growth phase. Pending the potential FDA approval of our lead drug candidate Zilretta, over the next 6-12 months we will significantly increase our commercial infrastructure, establish a national field force and expand our team of Medical and Scientific Liaisons. We presently have 100 full time employees, and we anticipate we will grow to approximately 250 by the end of 2017. While top of mind for us is ensuring Zilretta’s success, we do intend to expand our pipeline with a particular focus on local therapies for musculoskeletal disease. We should have more to report on that in the coming year.”

Asked about the biggest challenges of pulling this NDA together, he noted, “As this was Flexion’s first NDA, and first electronic submission, it had to be built from ground zero. It was therefore vital that we hired the right internal talent and vendors to produce the highest quality NDA from both a content and administrative perspective. The integration of late-arriving information (e.g., newly finalized clinical study reports or updated stability data on the drug product) across the various aspects of the NDA while maintaining the submission timeline always poses a major challenge. We are pleased to have successfully managed these challenges which allowed us to achieve this major milestone on time.”