Reunion Neuroscience Abstract Accepted for Poster Presentation at 2023 ASCP Annual Meeting

Reunion Neuroscience Inc. (NASDAQ: REUN, TSX: REUN) (“Reunion” or “the Company”), a clinical-stage biopharmaceutical company committed to developing innovative and patented therapeutic solutions for underserved mental health conditions, announced today that the Company’s first-in-human results for lead asset, RE104, have been accepted for a poster presentation at the 2023 American Society of Clinical Psychopharmacology (ASCP) Annual Meeting, taking place on May 30 through June 2 in Miami. Dr. Robert Alexander, Reunion’s Chief Medical Officer, will share the findings on RE104, a proprietary, novel serotonergic psychedelic being developed as a potential fast-acting and durable treatment for patients suffering from postpartum depression (PPD) and other mental health conditions.

Previously reported key takeaways from the interim dataset from the Phase 1 study include:

• RE104 was shown to be safe and well tolerated, with no serious or severe adverse events.
• RE104 showed robust and pervasive pharmacodynamic effects with a shorter duration of psychedelic experience relative to published data with psilocybin (approximately three to four hours for RE104 versus six to eight hours for psilocybin).
• Reunion identified a dose level where participants receiving a single administration of RE104 achieved a quality pharmacodynamic response that, in other psychedelic treatment trials, has been shown to correlate with therapeutic response for patients with depression, anxiety and substance use disorder.

“For the first time, Reunion will be presenting data from all six cohorts of our Phase 1 clinical trial results, along with our anticipated Phase 2 clinical trial plans, at the ASCP Annual Meeting,” said Greg Mayes, President and CEO, Reunion Neuroscience. “The standard of care available to new moms suffering from PPD is unacceptable. PPD affects one in eight mothers and is believed to be a significant contributing factor to rising maternal death rates. As the only psychedelic asset in the clinic targeting the PPD indication in the U.S., single-dose RE104 could potentially provide mothers with fast-acting symptom relief and a quick return to essential mother-child bonding and breastfeeding. We look forward to presenting these promising results as we continue to advance RE104 in the clinic.”

A total of 48 subjects across all six cohorts have now completed study drug administration and will be included in the final analysis of safety, pharmacokinetics and pharmacodynamics.

About Reunion Neuroscience Inc.Reunion is committed to developing innovative therapeutic solutions for underserved mental health conditions. The Company’s lead asset, RE104, a proprietary, novel, serotonergic psychedelic compound and the only 4-OH-DiPT prodrug in clinical development, is being developed as a potential treatment for postpartum depression that could provide rapid symptom relief and durable efficacy. RE104 is protected under U.S. Patent No. 11,292,765 issued on April 5, 2022 (priority June 30, 2020), with claims for composition of matter, methods of manufacturing, formulations and methods of use for a genus of hemi-ester tryptamines, including RE104, which could provide protection out to June 30, 2041. Reunion is also developing the RE200 series, which includes preclinical compounds with enhanced receptor selectivity to address additional therapeutic applications.

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Cautionary Note Regarding Forward-Looking Information

This release includes forward-looking information (within the meaning of Canadian securities laws and within the meaning of the United States Private Securities Litigation Reform Act of 1995) regarding Reunion and its business. Often but not always, forward-looking information can be identified by the use of words such as “expect”, “intends”, “anticipates”, “plans”, “believes” or variations (including negative variations) of such words and phrases, or state that certain actions, events or results “may”, “could”, “would”, “should” or “will” be taken, occur or be achieved. Such statements are based on the current expectations and views of future events of the management of Reunion and are based on assumptions and subject to risks and uncertainties, many of which are beyond Reunion’s control. Although the management of Reunion believes that the assumptions underlying these statements are reasonable, they may prove to be incorrect. The forward-looking events and circumstances discussed in this release may not occur and could differ materially as a result of known and unknown risk factors and uncertainties affecting the companies, including the funds available to Reunion and the use of such funds, the timing, completion and potential outcome of testing and research on Reunion’s drug trial candidates, RE104 and the RE200 Series, including the ability to recruit patients, to retain and identify clinical partners, and to optimize dosage amounts, the likelihood and ability of Reunion to complete an investigational new drug application and obtain regulatory approvals, as required, prior to initiating further clinical trials for RE104 and molecules within the RE200 Series, the ability of Reunion to meet eligibility requirements for clinical testing and through to more complex clinical trials, the ability of Reunion to protect and expand its intellectual property portfolio, the performance of Reunion’s affiliate, Field Trip Health & Wellness Ltd., the ability of Reunion to produce and supply its drug trial candidates, market conditions, economic factors, management’s ability to manage and to operate the business, the equity markets generally and this and other Risk Factors disclosed in Reunion’s public filings available on the SEDAR website at www.sedar.com and on the EDGAR section of the SEC’s website at www.sec.gov. Although Reunion has attempted to identify important factors that could cause actual actions, events or results to differ materially from those described in forward-looking statements, there may be other factors that cause actions, events or results to differ from those anticipated, estimated or intended. Accordingly, readers should not place undue reliance on any forward-looking statements or information. No forward-looking statement can be guaranteed. Except as required by applicable securities laws, forward-looking statements speak only as of the date on which they are made (or such earlier date, if identified) and Reunion does not undertake any obligation to publicly update or revise any forward-looking statement, whether as a result of new information, future events, or otherwise. Additional information relating to Reunion, including its Annual Information Form and Risk Factors, can be located on the SEDAR website at www.sedar.com and on the EDGAR section of the SEC’s website at www.sec.gov.

This press release does not constitute an offer to sell or the solicitation of an offer to buy securities.

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Reunion Neuroscience:Greg MayesPresident & CEO(215) [e-mail]

Media Contact:         Shana Marino KCSA Strategic Communications(347) [e-mail]