You are here

Flexion Therapeutics to Present Results from Phase 2 Trial Evaluating ZILRETTA® (triamcinolone acetonide extended-release injectable suspension) in Bilateral Knee OA at 2018 ACR Annual Meeting

  • Data presented at 2018 American College of Rheumatology (ACR) Annual Meeting show concurrent, bilateral administration of ZILRETTA appeared safe and well tolerated
  • Systemic exposure to triamcinolone acetonide was 10-fold lower with ZILRETTA compared to traditional immediate-release TAcs
  • Four out of five people with osteoarthritis of the knee will eventually develop the disease in both knees

BURLINGTON, Mass., Oct. 22, 2018 (GLOBE NEWSWIRE) -- Flexion Therapeutics, Inc. (Nasdaq:FLXN) today will present the results from a Phase 2 clinical trial evaluating the pharmacokinetics (PK) and safety of concurrent administration of ZILRETTA (triamcinolone acetonide extended-release injectable suspension) in patients with bilateral osteoarthritis (OA). Results indicate that bilateral injections of ZILRETTA were well tolerated and resulted in substantially lower plasma concentrations of triamcinolone acetonide compared to immediate-release triamcinolone acetonide in crystalline suspension (TAcs). These data will be presented in a poster session at the 2018 American College of Rheumatology (ACR) Annual Meeting in Chicago, Illinois (Abstract 1371).

“Typically, physicians do not treat OA with corticosteroid injections in both knees at the same time due to concerns about potential systemic overexposure, which may require patients to return at a separate office visit to receive treatment in the second knee,” said Scott Kelley, M.D., Chief Medical Officer of Flexion. “These results suggest that the extended-release formulation of ZILRETTA may result in substantially lower systemic concentrations of triamcinolone acetonide following bilateral injections compared to traditional immediate-release steroids. The findings add to the robust and growing body of data that has been generated to provide clinicians with a deeper understanding of ZILRETTA’s clinical profile.”

Key findings from the study showed:

  • Exposure to triamcinolone acetonide was significantly lower in patients given ZILRETTA compared to those given TAcs, with maximum plasma concentrations nearly 10-fold lower (2,577.8 pg/mL compared to 24,289.4 pg/mL);
  • Safety profiles were similar for ZILRETTA and TAcs treatment groups, and both treatments were generally well tolerated; neither bilateral injections of ZILRETTA nor TAcs resulted in prolonged decreases in systemic cortisol production; and
  • There were no serious treatment emergent adverse events (TEAEs) and no patients discontinued the study.

The Phase 2 open-label study randomized 24 people with bilateral OA to receive concurrent injections of either ZILRETTA or TAcs in both knees. The most common TEAE related to study drug in patients given ZILRETTA was injection site pain (1 patient, 8.3%).  In patients given TAcs, the most common TEAEs related to study drug were arthralgia (1 patient, 8.3%) and joint swelling (1 patient, 8.3%).

OA of the knee affects more than 15 million Americans, with many people experiencing chronic pain as the disease progresses. Bilateral OA of the knee is common and typically develops over time in people showing symptoms in one knee, with 80% developing pain in both knees after 12 years.

Indication and Select Important Safety Information for ZILRETTA

Indication: ZILRETTA is indicated as an intra-articular injection for the management of osteoarthritis pain of the knee. It is not intended for repeat administration.

Contraindication: ZILRETTA is contraindicated in patients who are hypersensitive to triamcinolone acetonide, corticosteroids or any components of the product.

Warnings and Precautions:

  • Intra-articular Use Only: ZILRETTA has not been evaluated and should not be administered by epidural, intrathecal, intravenous, intraocular, intramuscular, intradermal, or subcutaneous routes. ZILRETTA should not be considered safe for epidural or intrathecal administration.
  • Serious Neurologic Adverse Reactions with Epidural and Intrathecal Administration: Serious neurologic events have been reported following epidural or intrathecal corticosteroid administration. Corticosteroids are not approved for this use.
  • Hypersensitivity reactions: Serious reactions have been reported with triamcinolone acetonide injection. Institute appropriate care if an anaphylactic reaction occurs.
  • Joint infection and damage: A marked increase in joint pain, joint swelling, restricted motion, fever and malaise may suggest septic arthritis. If this occurs, conduct appropriate evaluation and if confirmed, institute appropriate antimicrobial treatment.

Adverse Reactions: The most commonly reported adverse reactions (incidence ≥1%) in clinical studies included sinusitis, cough, and contusions.

Please see for full Prescribing Information.

On October 6, 2017, ZILRETTA was approved by the U.S. FDA as the first and only extended-release intra-articular therapy for patients confronting osteoarthritis-related knee pain. ZILRETTA 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 over 12 weeks.

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 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, and approximately five million OA patients receive either an immediate-release corticosteroid 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, a type of degenerative arthritis. The company's core values are focus, ingenuity, tenacity, transparency and fun. For the past two 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.

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; ZILRETTA's market potential and potential benefits; the proportion of knee OA patients that will eventually develop the disease in both knees; and expected increases in the rate of individuals with OA of the knee; the potential efficacy and safety profile of ZILRETTA for patients receiving bilateral injections, 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 associated with developing and obtaining regulatory approval for product candidates; the fact that results of past clinical trials may not be predictive of subsequent trials; risks associated with commercializing new pharmaceutical products in the United States; the risk that we may not be able to successfully maintain an effective sales force or product supply to commercialize ZILRETTA; competition from alternative therapies; the risk that we may not be able to maintain and enforce our intellectual property, including intellectual property related to ZILRETTA; the risk that ZILRETTA may not be successfully commercialized, including as a result of limitations in ZILRETTA's label and package insert information; risks regarding our ability to obtain adequate reimbursement from payers for ZILRETTA; risks related to the manufacture and distribution of ZILRETTA, including our reliance on sole sources of supply and distribution; risks related to key employees, markets, economic conditions, health care reform, prices and reimbursement rates; the risk that we may use our capital resources in ways that we do not currently expect; and other risks and uncertainties described in our filings with the Securities and Exchange Commission (SEC), including under the heading "Risk Factors" in our Quarterly Report on Form 10-Q for the quarter ended June 30, 2018 filed with the SEC on August 7, 2018 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.


Scott Young
Vice President, Corporate Communications & Investor Relations
Flexion Therapeutics, Inc.
T: 781-305-7194

Julie Downs
Manager, Corporate Communications
Flexion Therapeutics, Inc.
T: 781-305-7137

Monday, October 22, 2018 - 07:30