Flexion Therapeutics Presents ZILRETTA® (triamcinolone acetonide extended-release injectable suspension) Efficacy Data at the AAHKS and ACR Annual Meetings

Burlington, Massachusetts, UNITED STATES

  • Post-hoc sensitivity analysis assessed efficacy in patients who reported moderate-to-severe osteoarthritis (OA) pain prior to treatment on both ADP and WOMAC-A scales
  • In this analysis of concordant pain reporters, ZILRETTA provided durable pain relief that was statistically significant and clinically meaningful compared with immediate-release triamcinolone acetonide

BURLINGTON, Mass., Nov. 11, 2019 (GLOBE NEWSWIRE) -- Flexion Therapeutics, Inc. (Nasdaq:FLXN) today announced results from a sensitivity analysis evaluating the treatment effects of a single administration of ZILRETTA (triamcinolone acetonide extended-release injectable suspension) in patients with moderate-to-severe osteoarthritis (OA) pain on both the Average Daily Pain (ADP) and WOMAC-A1 (pain) scales. The post-hoc analysis of data from the pivotal Phase 3 trial indicated that in patients who reported moderate-to-severe pain at baseline on the two reporting instruments, ZILRETTA provided statistically significant and clinically meaningful pain relief compared with immediate-release triamcinolone acetonide in crystalline suspension (TAcs) and placebo.

The findings suggest that pre-treatment concordance across two pain assays may serve as an important patient eligibility criterion in future clinical trials. The data was presented in a poster session (Poster: 285) on November 8 at the recent American Association of Hip and Knee Surgeons (AAHKS) Annual Meeting. An encore presentation of these findings will be given at the American College of Rheumatology Annual Meeting (Abstract: 1309) on Monday, November 11, 2019 from 9:00-11:00 a.m. ET.

“The results indicate that concordant pain reporters may be better able to discern treatment effect. Our analysis revealed that a number of study participants had elevated baseline ADP scores compared to WOMAC-A pain scores prior to treatment,” said Scott Kelley, M.D., Chief Medical Officer of Flexion. “Baseline score inflation can occur when a minimum pain level is required to meet the trial enrollment criteria and may bias studies toward a reduced estimate of treatment effect. This analysis suggests that the use of multiple assays may be an important consideration in patient selection criteria as it may provide a more accurate picture of patients’ baseline pain.”

Study participants received either a single injection of ZILRETTA, TAcs or placebo. Patient-reported ADP‐intensity, WOMAC-A scores, and rescue medication usage were assessed throughout the study, and 60.3% (292/484) of patients with knee OA (Kellgren-Lawrence Grade 2-3) reported moderate-to-severe OA pain at baseline using both instruments (ADP ≥5 to ≤9 and WOMAC-A ≥2). 

In concordant pain reporters:

  • ZILRETTA significantly (P<0.05) improved ADP scores compared with TAcs (Weeks 5-19) and placebo (Weeks 1-20), and the proportion of patients reporting no knee pain (ADP score=0) at Week 12 was higher with ZILRETTA (~28%) compared with TAcs (~8%);
  • ZILRETTA significantly (P<0.05) improved WOMAC-A scores at Weeks 4, 8, and 12 (ZILRETTA vs TAcs) and Weeks 4, 8, 12 and 16 (ZILRETTA vs placebo);
  • ZILRETTA significantly (P<0.05) reduced rescue medication use from Weeks 2-20 (ZILRETTA vs TAcs) and Weeks 1-24 (ZILRETTA vs placebo); and
  • Baseline characteristics and adverse event profiles were consistent with those of the overall Phase 3 population.

The results of this post hoc analysis may have implications for study design and patient recruitment of future trials evaluating efficacy of intra-articular interventions for OA knee pain.

Indication and Select Important Safety Information for ZILRETTA® (triamcinolone acetonide extended-release injectable suspension)

Indication: ZILRETTA (triamcinolone acetonide extended-release injectable suspension) 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 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 knee pain for 12 weeks, with some people experiencing pain relief through Week 16. Learn more at www.zilretta.com.

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. For the past three years, Flexion has been named one of the Best Places to Work by the Boston Business Journal, and Flexion was recognized as a Top Place to Work in Massachusetts by The Boston Globe in 2017 and 2018. Visit flexiontherapeutics.com.

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; potential implications of data analysis for future clinical trial designs; expected increases in the rate of individuals with OA of the knee; 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; risks inherent in clinical development and the regulatory approval process, including the risk that future clinical results will not be consistent with prior results; risks related to the market and market conditions; 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 September 30, 2019 filed with the SEC on November 7, 2019 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
Senior Manager, Corporate Communications & Investor Relations
Flexion Therapeutics, Inc.
T: 781-305-7137

1. WOMAC (Western Ontario and McMaster Universities Arthritis Index) is a validated, widely used, proprietary set of standardized questionnaires used by health professionals to evaluate the condition of patients with osteoarthritis of the knee and hip, including pain, stiffness and physical functioning of the joints.