Flexion Therapeutics Announces Virtual Poster Presentations for FX201, an Intra-Articular Gene Therapy Candidate for the Treatment of Osteoarthritis, at the American Society of Gene & Cell Therapy Annual Meeting

• FX201 preclinical in vivo data in a rodent model of OA showed slowing of disease progression 12 weeks post-surgery, persistence of the vector genome in the joint for at least 92 days with absence of systemic distribution, and a favorable safety profile
  
  
• Productivity, purification yields, and product quality from FX201 manufacturing studies demonstrate capable manufacturing process to support FX201 clinical trials

BURLINGTON, Mass., May 05, 2020 (GLOBE NEWSWIRE) -- Flexion Therapeutics, Inc. (Nasdaq:FLXN) will present positive data from two studies of FX201, an investigational gene therapy for osteoarthritis (OA), at the American Society of Gene and Cell Therapy (ASGCT) Annual Meeting taking place virtually May 12-15, 2020. The abstracts were published in the May supplement of .

“The data from the rodent model served as a basis for the FX201 IND and reinforce our belief that FX201 holds the potential to become a transformative therapy for OA,” said Michael Clayman, M.D., President and Chief Executive Officer of Flexion. “Further, we are delighted to be presenting manufacturing studies at ASGCT which demonstrate a capable Good Manufacturing Process (GMP) to support the production of FX201 for our clinical trials.”  

Establishing the Efficacy, Safety, and Biodistribution of FX201, a Helper-Dependent Adenoviral Gene Therapy for the Treatment of Osteoarthritis, in a Rat Model (Abstract 747)

Flexion assessed the efficacy of HDAd-rat-IL-1Ra, the rat surrogate of FX201, in a rodent surgical model of OA. Efficacy was assessed after a single intra-articular administration one week post-surgery via histopathology at Week 12 using a semi-quantitative microscopic grading system (Osteoarthritis Research Society International [OARSI] score) for OA-related cartilage, synovium, and bone changes. In addition, two Good Laboratory Practice (GLP) studies were performed in a rodent model of OA to evaluate the safety and biodistribution of FX201 and the rat surrogate (a helper-dependent adenovirus vector with a transgene encoding rat variant of IL-1Ra) administered four weeks post-surgery. Key study findings include:

• HDAd-rat-IL-1Ra demonstrated a dose-dependent decrease in OARSI composite scores (a validated histopathologic measure of disease severity) in rats compared with placebo at 12 weeks post-surgery; 
  
  
  
  
• HDAd-rat-IL-1Ra had no adverse effects on mortality, body weight, food consumption, laboratory values or tissue assessments in rats at any dose evaluated;
  
  
  
  
• FX201 rat surrogate and FX201 vector genomes persisted for at least 92 days in the injected joint and proximal tissues without evidence of vector spreading via circulation.

Development of a Highly Productive and Reproducible Manufacturing Process for FX201, a Novel Helper-Dependent Adenovirus-Based Gene Therapy for Osteoarthritis (Abstract 1273)

Using a fit-for-purpose manufacturing process suitable for early development, Flexion successfully produced four batches of drug substance, which will enable GLP toxicology, pharmacology, and GMP clinical studies. Key findings include:

• Across three batches of FX201 and one batch of FX201 rat surrogate, the batch productivity and yields were consistent and met acceptable quality attributes for the intended use in toxicology, pharmacology, and clinical studies;
  
  
  
  
• Human IL-1Ra expression was tested using a cell-based assay for three batches of FX201 and demonstrated consistent levels of expression;
  
  
  
  
• A single GMP batch of drug substance yielded sufficient drug product for a Phase 1 study evaluating safety and tolerability of a 100-fold dose range of total genome copy number in up to 24 patients (NCT04119687); and
  
  
  
  
• A capable manufacturing process has been established that should support the FX201 gene therapy program through to proof-of-concept.

About FX201

FX201 is a locally administered gene therapy product candidate which utilizes a helper-dependent adenovirus (HDAd) vector, 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 osteoarthritis (OA). By persistently suppressing inflammation, Flexion believes FX201 holds the potential to both reduce OA pain and modify the disease.

About Osteoarthritis (OA) of the Knee

OA, also known as degenerative joint disease, affects more than 30 million Americans and accounts for more than $185 billion in annual expenditures. In 2017, approximately 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, approximately five million OA patients receive either a corticosteroid (immediate-release or extended-release) or hyaluronic acid intra-articular injection to manage their knee pain.

About Flexion Therapeutics

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, the most common form of arthritis. The company's core values are focus, ingenuity, tenacity, transparency and fun. Visit . 

Forward-Looking Statements

This release contains forward-looking statements that are based on the current expectations and beliefs of Flexion. Statements in this press release regarding matters that are not historical facts, including, but not limited to, statements relating to the future of Flexion; expected increases in the rate of individuals with OA of the knee; and the potential therapeutic and other benefits of FX201, are forward looking statements. These forward-looking statements are based on management's expectations and assumptions as of the date of this press release and are subject to numerous risks and uncertainties, which could cause actual results to differ materially from those expressed or implied by such statements. These risks and uncertainties include, without limitation, risks related to clinical trials, including potential delays, safety issues or negative results; risks related to key employees, markets, economic conditions, and health care reform; and other risks and uncertainties described in our filings with the Securities and Exchange Commission (SEC), including under the heading "Risk Factors" in our Annual Report on Form 10-K filed with the SEC on March 12, 2020 and subsequent filings with the SEC. The forward-looking statements in this press release speak only as of the date of this press release, and we undertake no obligation to update or revise any of the statements. We caution investors not to place considerable reliance on the forward-looking statements contained in this press release.

Contacts:

Scott Young

Vice President, Corporate Communications & Investor Relations

Flexion Therapeutics, Inc.

T: 781-305-7194

Julie Downs

Associate Director, Corporate Communications & Investor Relations

Flexion Therapeutics, Inc.

T: 781-305-7137