Flexion Therapeutics Announces Publication of Results from Phase 2 Pharmacokinetics (PK) and Safety Study of ZILRETTA® in Shoulder Osteoarthritis (OA)

Flexion Therapeutics, Inc. (Nasdaq:FLXN) announced that the results from the randomized, open-label, Phase 2 pharmacokinetic (PK) trial of ZILRETTA (triamcinolone acetonide extended-release injectable suspension) were published in Drugs in R&D.

  • Data published in Drugs in R&D confirms extended-release PK profile of ZILRETTA (triamcinolone acetonide extended-release injectable suspension) in patients with shoulder OA
  • Plasma PK data indicate the total and maximal exposure to triamcinolone acetonide (TA) was approximately two-thirds lower in patients treated with ZILRETTA compared to triamcinolone acetonide in crystalline suspension (TAcs)
  • Registration trial in patients with shoulder OA expected to begin later this year

BURLINGTON, Mass., Aug. 09, 2021 (GLOBE NEWSWIRE) -- Flexion Therapeutics (Nasdaq:FLXN) announced that the results from the randomized, open-label, Phase 2 pharmacokinetic (PK) trial of ZILRETTA (triamcinolone acetonide extended-release injectable suspension) were published in Drugs in R&D. The study compared the plasma PK profile of ZILRETTA to immediate-release triamcinolone acetonide in crystalline suspension (TAcs) and assessed the safety and general tolerability of ZILRETTA in osteoarthritis (OA) of the shoulder.

“Shoulder OA pain can significantly impact a person’s quality of life; however, there are currently no FDA approved pharmacologic treatments for this common and debilitating condition,” said Michael Clayman, M.D., President and Chief Executive Officer of Flexion. “The publication of these data demonstrate that ZILRETTA’s release profile in the shoulder is consistent with what we observed in the knee, and they strengthen our confidence in the potential for our product to make a meaningful difference in the lives of people confronting OA shoulder pain.”

In the Phase 2, randomized, open-label, single-dose study, 25 adults with moderate to severe shoulder OA received a single ultrasound-guided intra-articular (IA) injection of either ZILRETTA (n=12) or TAcs (n=13). All patients were evaluated for 12 weeks post-injection. PK and safety profiles of ZILRETTA were similar to those reported in Phase 3 studies of patients with knee OA. Plasma PK findings from this study were also consistent with the extended release of triamcinolone acetonide (TA) within the synovial fluid following an IA injection of ZILRETTA in the knee. Extended release may enable sustained analgesic effect in the shoulder.

Key topline results include:

  • In patients treated with ZILRETTA the total and maximal exposure to TA was approximately two-thirds lower when compared to TAcs.
    • Following an injection of ZILRETTA, plasma TA concentration peaked at four hours post-injection, was sustained over the ensuing 24 hours, and then declined slowly during the remainder of the study.
  • There were no serious adverse events (AEs) and no AEs led to study discontinuation in either treatment group.

Flexion plans to initiate a registration trial to further investigate ZILRETTA in shoulder OA later this year.

ZILRETTA is currently approved for the management of OA pain of the knee. ZILRETTA is not approved as a treatment for shoulder OA.

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.

Limitation of Use: The efficacy and safety of repeat administration of ZILRETTA have not been demonstrated.

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 ZilrettaLabel.com 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. The pivotal Phase 3 trial on which the approval of ZILRETTA was based showed that ZILRETTA significantly reduced OA knee pain for 12 weeks, with some people experiencing pain relief through Week 16. Learn more at www.zilretta.com.

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. Please visit flexiontherapeutics.com.

Forward-Looking Statements
This press 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 timing and plans with respect to further clinical development of ZILRETTA in shoulder OA; and the potential therapeutic and other benefits of ZILRETTA, 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, the fact that the impacts and expected duration of the COVID-19 pandemic are uncertain and rapidly changing; the risk that we may not be able to maintain and enforce our intellectual property, including intellectual property related to ZILRETTA; risks related to clinical trials, including potential delays, safety issues or negative results; 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 March 31, 2021 filed with the SEC on May 12, 2021 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
Associate Director, Corporate Communications & Investor Relations
Flexion Therapeutics, Inc.
T: 781-305-7137

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