5-MeO-DMT

Phase 2b results for GH001 in TRD now published and peer-reviewed in JAMA Psychiatry New peer-reviewed article in forthcoming issue of Psychopharmacology Bulletin demonstrates that GH001 efficacy is independent of prior antidepressant treatment failures DUBLIN, March 25, 2026 (GLOBE NEWSWIRE) -- GH Research PLC (Nasdaq: GHRS), a clinical-stage biopharmaceutical company dedicated to transforming the lives of patients by developing a practice-changing treatment in depression, today announced two peer-reviewed publications from its Phase 2b clinical program of GH001 in treatment-resistant depression (TRD): the primary trial results in JAMA Psychiatry, and a new analysis demonstrating that efficacy is independent of the number of prior lifetime treatment failures in a forthcoming issue of Psychopharmacology Bulletin. JAMA Psychiatry Publication The peer-reviewed article, titled “GH001 vs Placebo in Patients with Treatment-Resistant Depression” has been published today in JAMA Psychiatry (DOI: 10.1001/jamapsychiatry.2026.0096). The publication includes the complete results from the randomized, double-blind, placebo-controlled Phase 2b trial of mebufotenin in patients with TRD, including all primary and secondary efficacy endpoints, safety and tolerability data, and initial results from the 6-month open-label extension. These results were previously reported in topline form. “Publication in JAMA Psychiatry provides independent peer-reviewed validation of our Phase 2b findings,” said Dr. Velichka Valcheva, Chief Executive Officer. “This supports our ongoing efforts to advance GH001 into global pivotal trials.” New Finding: GH001 Efficacy Is Independent of Prior Treatment Failures A supporting peer-reviewed article, titled “GH001 Efficacy is Independent of Prior Antidepressant Treatment Failures in Treatment-Resistant Depression: A Post Hoc Analysis of a Phase 2b Randomized Controlled Trial,” will be published in a forthcoming issue of Psychopharmacology Bulletin. In TRD, a well-established finding across multiple treatment modalities is that remission rates decline significantly with each successive antidepressant treatment failure. This pattern, first quantified in the landmark STAR*D trial (see About STAR*D below), represents a fundamental challenge in treating patients with extensive treatment histories. The new analysis of Phase 2b data demonstrates that GH001 does not follow this pattern: Day 8 remission rates ranged from 53.9% to 63.6% across patients with 2 to ≥5 prior lifetime antidepressant failures, with no decline at higher failure counts; End of trial/Month 6 remission rates ranged from 61.5% to 85.7% across the same subgroups; and No meaningful correlation was observed between the number of prior lifetime treatment failures and Montgomery-Åsberg Depression Rating Scale (MADRS) improvement at Day 8 (r=−0.13; P=0.44) or among those who completed the 6-month OLE (r=−0.10; P=0.60). “One interesting, unanticipated finding from this trial is that the benefit of GH001 appeared to be independent of the number of prior lifetime antidepressant failures. Remission rates were consistently high across subgroups – in contrast to the decline seen with each successive treatment that we observed in the STAR*D trial. This suggests patients who have not responded to three or more prior courses of antidepressant therapy might benefit from this novel therapy,” said Michael E. Thase, MD, Professor of Psychiatry, Perelman School of Medicine at the University of Pennsylvania. Consistent with the findings of this article, GH001 efficacy is also independent from prior treatment failures within the current depressive episode in this Phase 2b trial. About GH Research PLC GH Research PLC is a clinical-stage biopharmaceutical company dedicated to transforming the lives of patients by developing a practice-changing treatment in depression. GH Research PLC’s initial focus is on developing its novel and proprietary mebufotenin therapies for the treatment of patients with TRD. Based on the observed clinical activity in our Phase 2b trial, where the primary endpoint was met with a MADRS reduction from baseline of −15.5 points compared with placebo on Day 8 (P<0.0001), we believe that our mebufotenin product candidates have the potential to change the way TRD is treated today. About GH001 Our lead product candidate, GH001, is formulated for mebufotenin administration via a proprietary inhalation approach. Based on the observed clinical activity in our Phase 2b GH001-TRD-201 trial, where the primary endpoint was met with a MADRS reduction from baseline of −15.5 points compared with placebo on Day 8 (P<0.0001), we believe that GH001 has the potential to change the way TRD is treated today. About STAR*D The Sequenced Treatment Alternatives to Relieve Depression (STAR*D) trial was the largest and most comprehensive prospective study of depression treatment outcomes ever conducted. Funded by the National Institute of Mental Health (NIMH), the trial enrolled 4041 outpatients with major depressive disorder across 41 U.S. clinical sites between 2001 and 2004. The study used a sequential design in which patients who did not achieve remission on an initial antidepressant (citalopram) were moved through up to four successive treatment steps, each involving a switch to or augmentation with a different medication. STAR*D’s central finding was that remission rates declined progressively with each treatment step: 36.8% achieved remission after the first course, 30.6% after the second, 13.7% after the third, and just 13.0% after the fourth (Rush et al., American Journal of Psychiatry, 2006). Cumulatively, after all four steps, approximately one-third of patients had still not achieved remission. This pattern of diminishing returns with increasing treatment resistance has been widely replicated and is now considered a defining characteristic of TRD. Forward-Looking Statements This press release contains statements that are, or may be deemed to be, forward-looking statements. All statements other than statements of historical fact included in this press release, including statements regarding our plans and expectations with respect to our global Phase 3 pivotal program for GH001, strategies and prospects for our business, including the development and therapeutic potential of mebufotenin and GH001, are forward-looking statements. Forward-looking statements appear in a number of places in this press release and include, but are not limited to, statements regarding our intent, belief or current expectations. Forward-looking statements are based on our management’s beliefs and assumptions and on information currently available to our management. Such statements are subject to risks and uncertainties, and actual results may differ materially from those expressed or implied in the forward-looking statements due to various factors, including, but not limited to, those described in our filings with the U.S. Securities and Exchange Commission from time to time. No assurance can be given that such future results will be achieved. Such forward-looking statements contained in this press release speak only as of the date hereof. We expressly disclaim any obligation or undertaking to update these forward-looking statements contained in this press release to reflect any change in our expectations or any change in events, conditions, or circumstances on which such statements are based unless required to do so by applicable law. No representations or warranties (expressed or implied) are made about the accuracy of any such forward-looking statements. Investor Relations Julie Ryan GH Research PLC investors@ghres.com

Inclusion in U.S. CRSP® benchmark indices triggers mandatory position-building by passive index funds tracking more than $3 trillion in AUM, including the world’s largest mutual fundExpands market presence across the S&P Total Market Index, covering virtually all U.S.-listed equities, and the S&P Completion Index, which represents approximately 3,000 mid-, small-, and micro-cap companies not included in the S&P 500®Continues a series of index inclusions across the U.S. equity benchmark landscape, reflecting AtaiBeckley’s enhanced eligibility following its U.S. re-domiciliation and building on its addition to the Nasdaq Biotechnology Index in December 2025 NEW YORK, March 24, 2026 (GLOBE NEWSWIRE) -- AtaiBeckley Inc. (NASDAQ: ATAI) (“AtaiBeckley” or “Company”), a clinical-stage biotechnology company on a mission to transform patient outcomes by developing rapid-acting, durable and convenient mental health treatments, today announced its addition to the S&P Total Market Index, the S&P Completion Index and CRSP® U.S. benchmark indices, effective March 23, 2026. BPL-003 Phase 3 program remains on track to initiate in Q2 2026, and topline data from the VLS-01 Phase 2b study are expected in H2 2026. Srinivas Rao, Co-Founder and Chief Executive Officer of AtaiBeckley, said: "Being added to the S&P Total Market Index, S&P Completion Index, and CRSP U.S. benchmark indices reflects meaningful recognition of AtaiBeckley's enhanced presence in U.S. equity markets, with the CRSP index alone tracking more than $3 trillion in passively managed assets. These inclusions broaden our reach across index-tracking strategies and build on our earlier addition to the Nasdaq Biotechnology Index in December 2025. We see these additions as a natural progression as AtaiBeckley’s market profile grows alongside our advancing clinical pipeline, including BPL-003’s anticipated Phase 3 initiation in the second quarter." The S&P Total Market Index tracks virtually all U.S.-listed common stocks traded on the NYSE, NYSE American, NASDAQ National Market, and NASDAQ Small Cap exchanges, providing comprehensive coverage of the investable U.S. equity universe. The S&P Completion Index comprises all members of the S&P Total Market Index that are not current constituents of the S&P 500®, offering broad exposure to approximately 3,000 mid-, small-, and micro-cap U.S. companies. These indexes are widely used by institutional investors and asset managers as benchmarks for passive investment strategies. The CRSP® benchmark indices are maintained by the Center for Research in Security Prices, formerly a research center of the University of Chicago Booth School of Business and acquired by Morningstar, Inc. in February 2026, and serve as the basis for index funds representing more than $3 trillion in assets, including the world’s largest mutual fund. CRSP indexes are reconstituted quarterly and are routinely adopted by institutional investors, including Vanguard, as the basis for broad-market passive strategies. About AtaiBeckley Inc.AtaiBeckley is a clinical-stage biotechnology company on a mission to transform patient outcomes by developing rapid-acting, durable and convenient mental health treatments. AtaiBeckley’s pipeline of novel therapies includes BPL-003 (mebufotenin benzoate nasal spray) for treatment-resistant depression (TRD), VLS-01 (DMT buccal film) for TRD and EMP-01 ((R)-MDMA HCI) for social anxiety disorder. BPL-003 is in Phase 3 planning, VLS-01 and EMP-01 are in Phase 2 clinical development. The Company is also advancing a drug discovery program to identify novel, non-hallucinogenic 5-HT2AR agonists for opioid use disorder and TRD. These programs aim to create breakthroughs in mental health through transformative interventional psychiatry therapies that can integrate seamlessly into healthcare systems. For the latest updates and to learn more about the AtaiBeckley mission, visit www.ataibeckley.com or follow the Company on LinkedIn and on X. Forward-Looking StatementsThis press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995, as amended. We intend such forward-looking statements to be covered by the safe harbor provisions for forward-looking statements contained in Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended. The words “believe,” “may,” “will,” “estimate,” “continue,” “anticipate,” “intend,” “expect,” “anticipate,” “initiate,” “could,” “would,” “project,” “plan,” “potentially,” “preliminary,” “likely,” and similar expressions are intended to identify forward-looking statements, although not all forward-looking statements contain these words. Forward-looking statements include express or implied statements relating to, among other things: our business strategy and plans; the expected impact of the inclusion on the indices; the potential, success, cost and timing of development of our product candidates, including the progress of preclinical and clinical trials and related milestones; and the plans and objectives of management for future operations, research and development and capital expenditures. Forward-looking statements are neither promises nor guarantees, but involve known and unknown risks and uncertainties that could cause actual results to differ materially from those projected, including, without limitation, the important factors described in the section titled “Risk Factors” in our most recent Annual Report on Form 10-K filed with the Securities and Exchange Commission (“SEC”), as such factors may be updated from time to time in our quarterly reports and other filings with the SEC. AtaiBeckley disclaims any obligation to update or revise any forward-looking statements contained in this press release, other than to the extent required by applicable law.Contact Information:Investors: Jason Awe, PhDVP, Investor RelationsIR@ataibeckley.com Media: Charlotte ChorleyAssociate Director, CommunicationsPR@ataibeckley.com