FLXN Flexion Therapeutics Inc

Flexion Therapeutics, Inc. (Nasdaq:FLXN) today announced the expansion of the Phase 1b randomized, double-blind, placebo-controlled trial of FX301 in patients undergoing bunionectomy. FX301 is a novel formulation of a locally administered NaV1.7 inhibitor (funapide) which aims to provide at least three to five days of post-operative pain relief while preserving motor function. The company’s decision to advance FX301 into the expansion cohort follows a review of safety data from the single ascending dose stage of the trial by an independent Safety Monitoring Committee. Subsequently, an internal review committee assessed safety, systemic exposure and efficacy data and made the decision to advance the program.

“We are pleased that the initial findings from the four cohorts of the dose ranging data support the expansion of the trial in a selected dose,” said Michael Clayman, MD, President and Chief Executive Officer of Flexion Therapeutics. “We are excited to see the trial advance and look forward to sharing the results by the end of this year.”

The single ascending dose stage of the Phase 1b trial was designed to evaluate the safety and tolerability of four dosing cohorts of 12 patients each (9 active:3 placebo). In the expansion cohort, an additional 36 patients will be randomized (1:1) to receive either FX301 at the selected dose (130 mg/low volume) or placebo to further assess the safety, tolerability, systemic exposure, and efficacy of FX301 as a single-injection analgesic nerve block adjacent to the sciatic nerve of the popliteal fossa. 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 analgesic nerve block for control of post-operative pain. Flexion believes FX301 has the potential to provide effective 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, a type of degenerative 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 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; the fact that initial clinical results may not be predictive of final results from a trial or results from future trials; 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 for the year ended December 31, 2020 filed with the SEC on March 10, 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.

Contacts:

Scott YoungVice President, Corporate Communications & Investor RelationsFlexion Therapeutics, Inc.T: 781-305-7194syoung@flexiontherapeutics.com

Julie DownsAssociate Director, Corporate Communications & Investor Relations Flexion Therapeutics, Inc.T: 781-305-7137jdowns@flexiontherapeutics.com