Flexion Therapeutics Announces FDA Clearance Of Investigational New Drug Application For FX301, A Novel Formulation Of A Locally Administered NaV1.7 Inhibitor For Post-Operative Pain

• FX301 combines NaV1.7 inhibitor (funapide) with a proprietary thermosensitive hydrogel to facilitate administration as a peripheral analgesic nerve block
• FX301 may provide 3 to 5 days of non-opioid pain relief while preserving motor function following musculoskeletal surgery
• Proof of concept Phase 1b clinical trial in patients undergoing bunionectomy expected to begin in the first half of 2021

Burlington, MA (GLOBE NEWSWIRE) - Flexion Therapeutics, Inc. (Nasdaq:FLXN) today announced the U.S. Food and Drug Administration (FDA) cleared the Investigational New Drug (IND) application for FX301, a locally administered NaV1.7 inhibitor known as funapide, formulated for extended-release in a thermosensitive hydrogel. The selective pharmacology of funapide holds the potential to provide effective non-opioid pain relief for at least 3 to 5 days, while preserving extremity motor function which is typically compromised by local anesthetic peripheral nerve block.

“The IND clearance represents a key milestone for Flexion as we continue to advance our pipeline of important product candidates aimed at alleviating pain and improving outcomes for millions of people confronting musculoskeletal conditions along their continuum of care,” said Michael Clayman, MD, President and Chief Executive Officer of Flexion Therapeutics. “FX301 utilizes a proprietary formulation that was developed in our Innovation Lab and which converts from a liquid to a gel once it warms to body temperature following injection. We believe FX301 holds the unique potential to provide several days of meaningful post-operative pain relief as well as preserve the ability to ambulate and initiate rehabilitation following musculoskeletal surgery.”

The FDA’s clearance of the IND was supported by key preclinical data developed by Flexion and extensive clinical data associated with previous clinical trials investigating funapide in other indications. In a validated preclinical model of post-operative pain, FX301 administered as a peripheral nerve block demonstrated analgesic effect beginning at 1 hour post-dosing compared to placebo and significantly greater analgesic effect compared to liposomal bupivacaine at 36 hours post-dosing. Data from the study also indicated that treatment with FX301 did not significantly affect total walking distance in animals at 2 and 24 hours post-injection, whereas animals treated with liposomal bupivacaine experienced a significant reduction in total walking distance at those time points.

Flexion plans to initiate a Phase 1b proof of concept clinical trial of FX301 administered as a popliteal fossa block (a commonly used nerve block in foot and ankle-related surgeries) in patients undergoing bunionectomy and expects to treat the first patient in the first half of this year. Topline results from the trial are anticipated in late 2021.

About FX301
FX301 is an investigational locally administered NaV1.7 inhibitor known as funapide, formulated for extended release in a thermosensitive hydrogel. The initial development of FX301 is intended to support administration as a peripheral nerve block for control of post-operative pain. Flexion believes FX301 has the potential to provide meaningful pain relief for at least three to five days while preserving motor function.

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 arthritis. The Company's core values are focus, ingenuity, tenacity, transparency and fun. Please 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; timing and plans with respect to the Phase 1b clinical trial of FX301; and the potential therapeutic and other benefits of FX301, 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 FX301; 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 September 30, 2020 filed with the SEC on November 4, 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.

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