Flexion Announces Clearance of NDA for Gene Therapy Candidate


Flexion Therapeutics, Inc. recently announced clearance of the company’s Investigational New Drug (IND) application for FX201 in knee osteoarthritis (OA), a painful, chronic and progressive disease that affects more than 15 million adults living in the US. Flexion has initiated a Phase 1 multicenter, open-label, single ascending dose study and expects to treat the first patient by the end of this year.

“Disease progression in osteoarthritis involves multiple tissues in the joint, and in preclinical models of osteoarthritis, intra-articular injection of FX201 has demonstrated improvements in bone, cartilage and synovium as well as symptomatic benefit,” said Neil Bodick, MD, PhD, Chief Scientific Officer at Flexion. “We believe a single injection of FX201 will persistently provide therapeutic concentrations of IL-1Ra, a potent anti-inflammatory protein, with the potential to both provide long-term pain relief and modify disease progression.”

FX201 is a helper-dependent non-integrating adenovirus containing the human interleukin-1 receptor antagonist (IL-1Ra) gene under the control of an inflammation sensitive promoter. Preclinical data show that gene expression persists for at least one year, and IL-1Ra expression increases in response to inflammation. Nonclinical safety and efficacy data submitted in the IND application demonstrated that a single administration of FX201 was well-tolerated, had no significant biodistribution outside the target tissues, and pharmacology studies with the rat, mouse, and horse orthologues showed symptomatic improvement and delay in disease progression. Results showing dose-dependent decreases in the severity of cartilage and bone lesions following anterior cruciate ligament transection in rats will be presented at the American College of Rheumatology (ACR) annual meeting on Tuesday, November 12th at 9:00 a.m. ET (Abstract: 1974).

The Phase 1, multicenter, open-label, dose-escalation trial will evaluate the safety and tolerability of FX201 in male and female patients, 30-80 years of age, with painful OA of the knee. The study is expected to enroll up to 24 patients across six sites in the US.

“We expect this study to provide data characterizing dosing, safety, and tolerability as well as initial insight into clinical activity including effects on pain, function, and structural progression in OA,” said Javad Parvizi, MS, MD, FRC, orthopedic surgeon at the Rothman Institute and principal investigator for the study. “If successful, FX201 could be transformative in the treatment of knee OA.”

Prior to initiating the FX201 clinical program, Flexion formed a Scientific Advisory Board (SAB) of world-renowned gene therapy experts to provide on-going technical and strategic guidance as the company advances the clinical development of FX201. The appointments to Flexion’s Gene Therapy SAB include:

-Robert Kotin, PhD is the Scientific founder of Generation Bio. Previously he was the Vice President of production at Voyager Therapeutics. He is currently on the faculty at University of Massachusetts Medical School.

-Philip Reilly, MD, JD is a physician geneticist who helped found Bluebird bio and Voyager Therapeutics, two gene therapy companies that are publicly traded.

-Gregory Robinson, PhD is currently Chief Scientific Officer at Akouos. Previously, he served as the Chief Scientific Officer at Nightstar Therapeutics and Agilis Biotherapeutics.

-J. Fraser Wright, PhD is a co-founder of Spark Therapeutics, Inc. where he served as Chief Technology Officer. He is currently on the faculty at Stanford University.

-Dr. Wright commented, “In the development of a treatment for a prevalent, non-monogenic musculoskeletal disease, FX201 has the potential to open a new domain for gene therapies.”

As part of Flexion’s ongoing commitment to expand scientific understanding of OA, Flexion co-sponsored a study to evaluate the potential of machine learning to measure and predict disease progression and its effects on bone shape. At ACR, Dr. Bodick and co-authors will present the results from the study which used machine learning to evaluate magnetic resonance imaging (MRI) data from the Osteoarthritis Initiative to develop a three-dimensional OA bone shape model of disease progression. The study looked at 47,858 knee MRIs (9,433 knees; 5,031 without OA), taken at various time points over an eight year period, with the aim of establishing a relationship between structure and clinical outcomes. The findings will be presented on Tuesday, November 12th at 9:00 am ET (Abstract: 2196).

FX201 is a clinical stage, locally administered, gene therapy product candidate designed to stimulate the production of an anti-inflammatory protein, interleukin-1 receptor antagonist (IL-1Ra), whenever inflammation is present within the joint. Inflammation is a known cause of pain, and chronic inflammation is thought to play a major role in the progression of OA. By persistently suppressing inflammation, Flexion believes FX201 holds the potential to both reduce OA pain and modify the disease.

OA, also known as degenerative joint disease, affects more than 30 million adults living in the U.S. and accounts for more than $185 billion in annual expenditures. In 2016, more than 15 million Americans were diagnosed with OA of the knee and the average age of physician-diagnosed knee OA has fallen by 16 years, from 72 in the 1990s to 56 in the 2010s. The prevalence of OA is expected to continue to increase as a result of aging, obesity and sports injuries. Each year, more than 15 million Americans are treated for OA-related knee pain.

Flexion Therapeutics (Nasdaq:FLXN) is a biopharmaceutical company focused on the development and commercialization of novel, local therapies for the treatment of patients with musculoskeletal conditions, beginning with osteoarthritis, a common form of arthritis. The company’s core values are focus, ingenuity, tenacity, transparency and fun. For the past three years, Flexion has been named one of the Best Places to Work by the Boston Business Journal, and Flexion was also recognized as a Top Place to Work in Massachusetts by The Boston Globe in 2017 and 2018. Visit flexiontherapeutics.com.

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