6-K

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 6-K

REPORT OF FOREIGN PRIVATE ISSUER PURSUANT TO RULE 13a-16 OR 15d-16 UNDER

THE SECURITIES EXCHANGE ACT OF 1934

For the month of May, 2025.

Commission File Number: 001-40530

GH Research PLC

(Exact name of registrant as specified in its charter)

Joshua Dawson House

Dawson Street

Dublin 2

D02 RY95

Ireland

(Address of principal executive office)

Indicate by check mark whether the registrant files or will file annual reports under cover of

Form 20-F or Form 40-F:

INFORMATION CONTAINED IN THIS REPORT ON FORM 6-K

GH Research PLC (the “Company”) will attend the American Society of Clinical Psychopharmacology (“ASCP”) Annual Meeting, which is scheduled to take place from May 27-30, 2025 in Scottsdale, Arizona (the “Congress”).

The Company will present posters during the Congress.

A copy of the poster to be delivered in conjunction with the Pharmaceutical Pipeline Presentation session, presented by Michael E. Thase, is attached hereto as Exhibit 99.1.

A copy of the poster to be presented by Wiesław J. Cubała to be delivered during Poster Session II is attached hereto as Exhibit 99.2.

A copy of the poster to be presented by Claus Bo Svendsen to be delivered during Poster Session II is attached hereto as Exhibit 99.3.

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EXHIBIT INDEX

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SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

Exhibit 99.1

Safety and Efficacy of GH001 in Treatment-Resistant Depression: Results From a Phase 2b, Double-Blind, Randomized Controlled Trial  Michael E. Thase,1,2* Bernhard T. Baune,3 Narcís Cardoner,4 Rosa Maria Dueñas Herrero,5 Luboš Janů,6 John R. Kelly,7 Shane J. McInerney,8 Alexander Nawka,9 Tomáš Páleníček,10 Andreas Reif,11 Víctor Pérez Sola,12-15 Madhukar H. Trivedi,16 Velichka Valcheva,17 Eduard Vieta,18 Wiesław J. Cubała19  1Department of Psychiatry, University of Pennsylvania, Philadelphia, PA, USA; 2Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, PA, USA; 3Department of Psychiatry, University of Muenster, Muenster, Germany; 4Hospital Santa Creu i Sant Pau, Mental Health Research Group, Institut de Recerca Sant Pau, Universitat Autònoma de Barcelona, CIBERSAM Barcelona, Spain; 5Parc Sanitari Sant Joan de Deu Hospital de Dia de Numancia, Barcelona, Spain; 6A-Shine SRO, Pilsen, Czechia; 7Department of Psychiatry, Tallaght University Hospital, Dublin, Ireland; 8Department of Psychiatry, University Hospital Galway, Galway, Ireland; 9Institut Neuropsychiatrické Péče, Praha, Czechia;  10Psyon s.r.o., Prague, Czechia; 11Goethe University Frankfurt, University Hospital, Department of Psychiatry, Psychosomatic Medicine and Psychotherapy, Frankfurt, Germany; 12Mental Health Institute, Hospital del Mar, Barcelona, Spain; 13Neurosciences Research Group, Hospital del Mar Research Institute (IMIM), Barcelona, Spain; 14Department of Psychiatry and  Department of Experimental and Health Sciences, Pompeu Fabra University, Barcelona, Spain; 15Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM G21), Instituto de Salud Carlos III, Madrid, Spain; 16Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX, USA; 17GH Research, Dublin, Ireland; 18Hospital Clinic de Barcelona, Institute of Neuroscience, University of Barcelona, IDIBAPS, CIBERSAM, Barcelona, Catalonia, Spain; 19Department of Psychiatry, Faculty of Medicine, Medical University of Gdańsk, Gdańsk, Poland  *Presenting Author: Michael E. Thase; [email protected]  Methods  Trial Design  This Phase 2b multicenter trial consisted of two parts (Figure 1):  Double-blind part (described here): a randomized, double-blind, placebo-controlled trial with follow-up to 7 days postdose. Patients were randomized in a 1:1 ratio to receive an individualized dosing regimen (IDR) of up to three escalating doses of GH001 (6, 12, and 18 mg) or placebo on a single day; there was a 1-hour interval between doses  Open-label extension (OLE): a 6-month trial with up to five GH001 re-treatments administered depending on the patient’s clinical status  Patients were required to meet the trial criteria for TRD as assessed by a trial psychiatrist:  Recurrent or single MDD episode without psychotic features, with current episode of ≤2 years  Current major depressive episode based upon the Massachusetts General Hospital – Structured Assessment for Evaluation of Risk (MGH-SAFER) criteria interview  17-Item Hamilton Depression Rating Scale (HAM-D-17) total score ≥20  Nonresponse to ≥2 and ≤5 oral antidepressant treatments  Assessments  The primary endpoint of the double-blind part of this trial was mean change in Montgomery–Åsberg Depression Rating Scale (MADRS) from baseline to Day 8, as assessed by a blinded rater  Secondary endpoints included change in global disease severity as assessed by the Clinical Global Impression – Severity (CGI-S) Scale, anxiety as assessed by the Hamilton Anxiety Rating Scale (HAM-A), and quality of life as assessed by the Quality of Life Enjoyment and Satisfaction Questionnaire – Short Form (Q-LES-Q-SF)  Treatment-emergent adverse events (TEAEs) were assessed throughout the trial  Background  Treatment-resistant depression (TRD) affects approximately 30% of patients treated for major depressive disorder (MDD)1  Current therapies for TRD are limited and there is a large unmet need for treatments that offer rapid and sustained effects  Mebufotenin (5-methoxy-N,N-dimethyltryptamine [5-MeO-DMT]) is a non-selective serotonin (5-HT) agonist with high affinity for several receptor subtypes, including the 5-HT1A receptor2  GH001 is a synthetic form of mebufotenin for pulmonary inhalation3,4  Early-stage trials in healthy volunteers and patients with TRD suggest that GH001 is well tolerated and may have the potential to induce an ultra-rapid remission in depressive symptoms3,4  Objective  The aim of this double-blind, placebo-controlled trial was to investigate the safety and efficacy of GH001 in patients with TRD  References  Kubitz N, et al. PLoS One. 2013;8(10):e76882.  Shen H, et al. Curr Drug Metab. 2010;11(8):659-66.  Reckweg J, et al. Front Pharmacol. 2021;12:760671.  Reckweg JT, et al. Front Psychiatry. 2023;14:1133414.  Acknowledgments  This trial was sponsored by GH Research. The sponsor would like to thank the participants in the trial.  The sponsor would also like to thank the investigators who conducted this trial. Under the guidance of the authors, medical writing and editorial support were provided by Brian Brennan, PhD, and Claire Sweeney, PhD, of GH Research, and Jane Phillips, PhD, of OPEN Health. Primary analysis of the trial was conducted by the contract research organization Worldwide Clinical Trials. Additional analyses were conducted by Rachael MacIsaac, PhD, of GH Research.  Disclosures  MET: Grants – Acadia, Alkermes, Axsome, Intra-Cellular Therapies, Janssen, National Institute of Mental Health, Otsuka, Patient-Centered Outcomes Research Institute (PCORI), and Takeda. Advisory Boards – Autobahn Therapeutics, Axsome, Clexio Biosciences, Gerson Lehrman Group, GH Research, Lundbeck, Janssen, Johnson & Johnson, Luye Pharma, Merck, Object Pharma, Otsuka, Pfizer, Sage, Seelos Therapeutics, Sunovion, and Takeda. Royalties – American Psychiatric Association Foundation, Guilford Publications, Herald House, Wolters Kluwer,   and W W Norton & Company. BTB: Consultant – National Health and Medical Research Council (Australia).  Honoraria – Angelini, AstraZeneca, Biogen, BMS, Boehringer Ingelheim, Johnson & Johnson, LivaNova, Lundbeck,  Medscape, Otsuka, Pfizer, Roche, Servier, Sumitomo Pharma, Sunovion, Teva, and Wyeth. Advisory boards   – Biogen, Boehringer Ingelheim, Janssen-Cilag, LivaNova, Lundbeck, Medscape, Novartis, Otsuka, and Teva.  Research grants from private industries or nonprofit funds – AstraZeneca, BMBF (Germany), BMG (Germany),   DFG (Germany), ERA PerMed, Fay Fuller Foundation, Horizon Europe (European Union), James & Diana Ramsay Foundation (Adelaide), Johnson & Johnson, Lundbeck, La Marató de TV3, National Health and Medical Research Council (Australia), Sanofi-Synthélabo, and Wellcome Trust (UK). NC: Grants – Spanish Ministry of Health,   Spanish Ministry of Science and Innovation (CIBERSAM), Strategic Plan for Health Research and Innovation   (PERIS) 2016–2020, Recercaixa, and La Marató de TV3. Honoraria – Adamed, Elsevier, Exeltis, Janssen, Lundbeck, Pfizer, and Servier. Advisory Boards – Angelini, Esteve, Janssen, Lundbeck, Novartis, Pfizer, and Viatris. Lectures/ Meetings – Janssen, Lundbeck, and Pfizer. RMDH: Principal investigator – Beckley Psytech and GH Research.  Subinvestigator – Compass. LJ: Principal investigator – GH Research. JRK: Principal investigator – Compass, GH Research, and Transcend Therapeutics. Consultant – Clerkenwell Health. Grant funding – Health Research Board   (ILP-POR-2022-030, DIFA-2023-005, KTA-2024-002). SJM: Principal investigator – GH Research and Transcend Therapeutics. Honoraria – Janssen and Lundbeck. AN: Principal investigator – GH Research. TP: Principal   investigator – Compass, GH Research, MAPS, and Ketabon. Shares – Psychedelická klinika s.r.o., Společnost  pro podporu neurovědního výzkumu s.r.o., and AVI-X Aviation Experts s.r.o. Founder – PSYRES (Psychedelic   Research Foundation). Consultant – CB21 Pharma and GH Research. AR: Honoraria for lectures and/or advisory boards – AbbVie, Boehringer Ingelheim, Cyclerion, Compass, GH Research, Janssen, LivaNova, Medice, MSD, Newron, Sage/Biogen, and Shire/Takeda. Research grants – Medice and Janssen. VPS: Consultant, honoraria,   or grants – AB-Biotics, AstraZeneca, Bristol Myers Squibb, CIBERSAM, FIS-ISCiii, Janssen Cilag, Lundbeck,  Medtronic, Otsuka, and Servier. MHT: Advisory boards – Alto Neuroscience and Base Point Health Management. Consultant – Axsome, Biogen, Daiichi Sankyo, GH Research, Legion Health, Neurocrine Biosciences, Otsuka Pharmaceutical Europe, Otsuka Pharmaceutical Development & Commercialization, Otsuka Pharmaceutical, PureTech, and Takeda. Advisor – Cerebral Therapeutics, Circular Genomics, and Seaport Therapeutics. Scientific advisor – GreenLight VitalSign6. Board of Directors – Charities2Love. VV: Employee and stock option holder  of GH Research. EV: Grants – AB-Biotics, AbbVie, Almirall, AstraZeneca, Boehringer Ingelheim, Bristol Myers   Squibb, Celon, Cephalon, Dainippon Sumitomo Pharma, Elan, Ferrer, GH Research, GlaxoSmithKline, Janssen,   Lilly, Lundbeck, Orion, Otsuka, Pfizer, Sanofi Aventis, Servier, Sunovion, and Takeda. Honoraria – Abbott, AbbVie, Angelini, AstraZeneca, Bristol Myers Squibb, Cambridge University Press, Elsevier, Farmindustria, Ferrer, Galenica, GlaxoSmithKline, Janssen, Johnson & Johnson, Lilly, Lundbeck, Oxford University Press, Otsuka, Pfizer, Sanofi   Aventis, and Viatris. Advisory boards – AbbVie, Angelini, AstraZeneca, Biogen,   Biohaven, Bristol Myers Squibb, Celon, Compass, Ferrer, GH Research,   Gedeon Richter, HMNC, Idorsia, Janssen, Johnson & Johnson, Jazz, Lilly,   Lundbeck, Merck Sharp & Dohme, Novartis, Organon, Otsuka, Pfizer, Roche,  Sage, Sanofi Aventis, Servier, Shire, Sunovion, Takeda, and Teva. WJC: Grants – Acadia, Angelini, Beckley Psytech, GH Research, HMNC Brain Health, Intra-Cellular Therapies, Janssen, MSD, Neumora, Novartis, Otsuka, Recognify Life Sciences. Honoraria – Angelini, GH Research, Janssen, and Novartis. Advisory boards –   Douglas Pharmaceuticals, GH Research, Janssen, MSD, and Novartis (relationships reported within the last three years).  Figure 1. Clinical Trial Schematic  This trial was conducted under the supervision of qualified healthcare professionals, providing psychological support per standard of care, but without any planned psychotherapeutic intervention before, during, or after dosing  N=81  Randomization 1:1  GH001 IDR  Placebo IDR  Open-Label Extension (OLE)  For re-treatment (up to five GH001 IDRs), the patient must have met one of the following criteria:  MADRS score >18  MADRS score >10 and ≤18 and MADRS score ≤10 not observed at Day 8 of the prior treatment or at any visit since  MADRS score >10 and ≤18 and MADRS score >18 observed since the most recent observation of MADRS score ≤10  During the OLE, patients attended visits at Day 15 and Months 1, 2, 3, 4, 5, and 6a Additional clinic visits could be scheduled if required for medical reasons  MADRS  assessment  Month 6  Primary Endpoint  BL 2h D2 ΔMADRS  Day 1 Day 2 Day 8  Double-Blind Part  Patients transitioned directly from the double-blind part to the OLE  aPatients also attended assessment visits on Day 2 (phone call) and Day 8 after each re-treatment.  BL = Baseline; D = Day; h = Hour; IDR = Individualized dosing regimen; MADRS = Montgomery–Åsberg Depression Rating Scale.  Results  Double-Blind Part  A total of 81 patients with TRD were enrolled in the double-blind part (GH001 IDR, n=40; placebo IDR, n=41; Table 1)  Table 1. Patient Disposition and Characteristics in the Double-Blind Part  GH001 (n=40)  Placebo (n=41)  Patient Disposition  Completed double-blind part, n (%)  40 (100)  41 (100)  Patient Demographics Age, years, mean (SD) Female, n (%)  Race, White, n (%) BMI, kg/m2, mean (SD)  Previously used any psychedelic (lifetime), n (%)  41.6 (11.4)  24 (60.0)  40 (100)  24.8 (4.3)  4 (10.0)  43.9 (10.9)  22 (53.7)  41 (100)  27.5 (6.3)  5 (12.2)  Baseline Disease Characteristics HAM-D-17 total score, mean (SD) MADRS total score, mean (SD)  24.9 (2.7)  29 (5.4)  24.6 (2.3)  28.2 (4.6)  MDE History at Baseline  Mean (SD)  Number of MDEs ≥3, n (%)  Time since first depressive episode, years, mean (SD) Duration of current MDE, weeks, mean (SD)  2.1 (1.4)  14 (35.0)  11.3 (9.7)  50.8 (28.3)  2.0 (1.1)  13 (31.7)  12.2 (8.4)  63.3 (106.9)  Patients Receiving IDR Dosesa  First dose (6 mg GH001 or one placebo dose), n (%) Second dose (6+12 mg GH001 or two placebo doses), n (%)  Third dose (6+12+18 mg GH001 or three placebo doses), n (%)  9 (22.5)  21 (52.5)  10 (25.0)  0 (0)  0 (0)  41 (100)  Duration of PsEb  6 mg (or placebo first dose), minutes, median (range)  12 mg (or placebo second dose), minutes, median (range) 18 mg (or placebo third dose), minutes, median (range)  9.0 (2−35)  14.0 (4−50)  11.5 (8−50)  0 (0−15)  0 (0−5)  0 (0−7)  aUp to three doses of GH001 or placebo were administered to each patient. bIncludes all patients who received respective dose of GH001 or placebo, irrespective of total dose.  BMI = Body mass index; HAM-D-17 = 17-Item Hamilton Depression Rating Scale; IDR = Individualized dosing regimen; MADRS = Montgomery-Åsberg Depression Rating Scale; MDE = Major depressive episode; PsE = Psychoactive effects; SD = Standard deviation.  Change in MADRS total score from baseline to Day 8 was significantly greater with GH001 than with placebo (Figure 2)  – Statistically significant reductions were also observed in the GH001 group at 2 hours postdose and on Day 2  Figure 2. Primary Endpointa: Change in MADRS Total Score From Baseline to Day 8  LS mean difference vs placebo: −15.5 (P<0.0001)  Effect size: Cohen’s d = −2.0  0  −1.4  −1.5  −18.6  0.3  −15.2  LS Mean (±SE) Change From Baseline in MADRS Total Score  −5  −10  −15  −25  −20 −17.8  BL 2 hours Day 2 Day 8  GH001 (n=40) Placebo (n=41)  aFDA Guidance notes that efficacy with rapid-acting antidepressants generally should be demonstrated within 1 week, supporting a primary efficacy endpoint within this timeframe. BL = Baseline; FDA = Food and Drug Administration; LS = Least squares; MADRS = Montgomery-Åsberg Depression Rating Scale; SE = Standard error.  Presented at the American Society of Clinical Psychopharmacology Annual Meeting | Scottsdale, AZ, USA | May 27−30, 2025  On Day 8, remission (MADRS total score ≤10) and response (MADRS total score ≥50% reduction) were achieved in 57.5% and 60.0% of patients treated with GH001, respectively, compared with 0% in the placebo groups (Figure 3)  Figure 3. Percentage of Patients With Remission or Response Through Day 8 After Administration of GH001 IDR or Placebo IDR  GH001  Placebo  ****P<0.0001  Remission: MADRS total score ≤10 | Response: ≥50% reduction from baseline in MADRS total score  2.4%  4.9%  2.4%  Percentage of Patients With MADRS Remission or Response  100  90  80  70  60  50  40  30  20  10  0  2 Hours  Remission  2.4%  Response  Remission Response  Day 2  0.0% 0.0%  Remission Response  Day 8  ****  82.5%  ****  60.0%  NNT=2  ****  57.5%  NNT=2 ****  **** 77.5%  70.0%  NNT=2  ****  57.5%  IDR = Individualized dosing regimen; MADRS = Montgomery-Åsberg Depression Rating Scale; NNT = Number needed to treat.  GH001 led to improvements in anxiety and quality of life vs placebo (Figure 4)  Figure 4. Change From Baseline in HAM-A Total Score and Q-LES-Q-SF Total Score at Day 8  −11.1  GH001 (n=40)  −1.0  Placebo (n=41)  LS Mean Change From Baseline at Day 8  −6  −10  −12  LS mean difference vs placebo:  −10.0 (P<0.0001)  20.6  −0.9  GH001 Placebo  (n=37) (n=39)  LS Mean Change From Baseline at Day 8  HAM-A Total Score Q-LES-Q-SF Total Score  0 25  −2 20  −4 15  10  −8 5  0  −5  LS mean difference vs placebo:  21.5 (P<0.0001)  HAM-A = Hamilton Anxiety Rating Scale; LS = Least squares; Q-LES-Q-SF = Quality of Life Enjoyment and Satisfaction Questionnaire – Short Form.  Greater improvements from baseline in global illness severity were also observed with GH001 vs placebo (Figure 5)  Figure 5. CGI-S Scores at Baseline and Day 8  6 - Severely ill 5 - Markedly ill  4 - Moderately ill 3 - Mildly ill  2 - Borderline ill 1 - Normal  Percentage of Patients in Each CGI-S Category at Day 8  100  80  60  40  20  0  5.0  Baseline  27.5  55.0  12.5  14.6  70.7  14.6  70.7  45.0  10.0  22.5  GH001 (n=40) Placebo (n=41)  5.0  7.5 17.1  10.0  Day 8  Baseline  12.2  Day 8  Percentages are for each baseline category within treatment.  CGI-S = Clinical Global Impression – Severity; LS = Least squares; SE = Standard error.  Inhalation of GH001 was well tolerated; no serious TEAEs were reported, no TEAEs of flashbacks were reported, and all TEAEs were mild or moderate in severity (Table 2)  Table 2. Overall Summary of Adverse Events  Patients, n (%)  GH001 (n=40)  Placebo (n=41)  Any TEAE  29 (72.5)  3 (7.3)  Maximum severity of TEAEs Mild  Moderate Severe  14 (35.0)  15 (37.5)  0 (0)  2 (4.9)  1 (2.4)  0 (0)  Treatment-related TEAEs 29 (72.5) 1 (2.4)  Device-related TEAEs 1 (2.5) 0 (0)  Serious TEAEs 0 (0) 0 (0)  Treatment-related serious TEAEs 0 (0) 0 (0)  TEAEs leading to study drug withdrawal 0 (0) 0 (0)  TEAEs leading to early withdrawal from trial 0 (0) 0 (0)  AESIs 8 (20.0) 0 (0)  Death 0 (0) 0 (0)  17 (42.5)  8 (20.0)  8 (20.0)  3 (7.5)  3 (7.5)  0 (0)  0 (0)  0 (0)  1 (2.4)  0 (0)  Most common TEAEs (occurring in >5% of patients in either group) by Preferred Term Nausea  Salivary hypersecretion Paresthesia  Headache Dysgeusia  TEAEs were classified according to the Medical Dictionary of Regulatory Activities (MedDRA version 26.0). AESI = Adverse event of special interest; TEAE = Treatment-emergent adverse event.  Open-Label Extension  Preliminary results from the 63 patients who completed the OLE indicate that GH001 can maintain long-term remission from TRD, with 73.0% of patients (n=46) who completed the OLE in remission (MADRS total score ≤10) at 6 months  Completers (n=63) had a mean MADRS total score of 9.4 at 6 months  63.5% of completers (n=40) received 1−4 treatments with GH001  No drug-related serious TEAEs were reported in the OLE; one non-drug-related serious TEAE of Preferred Term status migrainosus was reported 73 days after the patient's most recent administration of the GH001 IDR.  Conclusions  Double-Blind Part  The primary endpoint was met: GH001 administered as an IDR led to significant MADRS reductions from baseline to Day 8 (−15.5 vs placebo)  Secondary endpoints: Remission rate of 57.5% at Day 8 (placebo, 0%) and improvements in anxiety, global disease severity, and quality of life were observed  Safety: GH001 was well tolerated  Open-Label Extension  GH001 can maintain long-term remission in TRD, with 73.0% of patients who completed the OLE in remission at 6 months  Durable effects with relatively infrequent treatment visits and ultra-rapid MADRS reduction  No drug-related serious TEAEs were reported in the OLE  LS Mean (SE) Change in CGI-S Score From Baseline at Day 8  GH001 (n=40) Placebo (n=41)  −2.4 (0.2) 0.1 (0.2)  LS mean difference vs placebo:  −2.5 (P<0.0001)

Exhibit 99.2

Safety and Tolerability of GH001 in Treatment-Resistant Depression: Results From a Phase 2b, Double-Blind, Randomized, Controlled Trial  Wiesław J. Cubała,1* Bernhard T. Baune,2 Narcís Cardoner,3 Rosa Maria Dueñas Herrero,4 Luboš Janů,5 John R. Kelly,6 Shane J. McInerney,7 Alexander Nawka,8 Tomáš Páleníček,9 Andreas Reif,10 Victor Perez Sola,11-14 Madhukar H. Trivedi,15 Velichka Valcheva,16 Eduard Vieta,17 Michael E. Thase18,19  1Department of Psychiatry, Faculty of Medicine, Medical University of Gdańsk, Gdańsk, Poland; 2Department of Psychiatry, University of Muenster, Muenster, Germany; 3Hospital Santa Creu i Sant Pau, Mental Health Research Group, Institut de Recerca Sant Pau, Universitat Autònoma de Barcelona, CIBERSAM Barcelona, Spain; 4Parc Sanitari Sant Joan de Deu Hospital de Dia de Numancia, Barcelona, Spain; 5A-Shine SRO, Pilsen, Czechia; 6Department of Psychiatry, Tallaght University Hospital, Dublin, Ireland; 7Department of Psychiatry, University Hospital Galway, Galway, Ireland; 8Institut Neuropsychiatrické Péče, Praha, Czechia; 9Psyon s.r.o., Prague, Czechia; 10Goethe University Frankfurt, University Hospital, Department of Psychiatry,  Psychosomatic Medicine and Psychotherapy, Frankfurt, Germany; 11Mental Health Institute, Hospital del Mar, Barcelona, Spain; 12Neurosciences Research Group, Hospital del Mar Research Institute (IMIM), Barcelona, Spain; 13Department of Psychiatry and Department of Experimental and Health Sciences, Pompeu Fabra University, Barcelona, Spain; 14Centro de Investigación Biomédica en  Red de Salud Mental (CIBERSAM G21), Instituto de Salud Carlos III, Madrid, Spain; 15Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX, USA; 16GH Research, Dublin, Ireland; 17Hospital Clinic de Barcelona, Institute of Neuroscience, University of Barcelona, IDIBAPS, CIBERSAM, Barcelona, Catalonia, Spain; 18Department of Psychiatry, University of Pennsylvania, Philadelphia, PA, USA; 19Corporal Michael J Crescenz Veterans Affairs Medical Center, Philadelphia, PA, USA  *Presenting Author: Wiesław J. Cubała; [email protected]  Methods  This two-part, Phase 2b trial (NCT05800860) enrolled patients with TRD (Figure 1)  The double-blind part (presented here) was a 7-day part in which patients were randomized 1:1 to receive an IDR of up to three escalating doses of GH001 (6, 12, and 18 mg) or placebo IDR on a single day  Patients in the 6-month open-label extension received up to five GH001 re- treatments depending on their clinical status (data not presented here)  This trial was conducted under the supervision of qualified healthcare professionals, providing psychological support per standard of care, but without any planned psychotherapeutic intervention before, during, or after dosing  Safety assessments (up to Day 8) included treatment-emergent adverse events (TEAEs), vital signs, electrocardiogram (ECG), laboratory assessments, and safety assessment tools (Columbia-Suicide Severity Rating Scale [C-SSRS], Brief Psychiatric Rating Scale positive symptoms subscale [BPRS+], Clinician-Administered Dissociative States Scale [CADSS], Modified Observer’s Assessment of Alertness and Sedation [MOAA/S] scale, and Clinical Assessment of Discharge Readiness [CADR])  Background  Treatment-resistant depression (TRD) is a chronic condition affecting approximately 30% of patients with major depressive disorder1  There are currently only two pharmacotherapies approved for the treatment of TRD, highlighting the unmet need for additional safe and effective treatments2  Early-phase clinical trials of GH001, a synthetic form of mebufotenin for pulmonary inhalation, in healthy volunteers and patients with TRD demonstrated it is well tolerated with an acceptable safety profile3,4  This trial evaluated the safety and tolerability of GH001 in patients with TRD in a randomized, double-blind, placebo-controlled setting  Objective  The objective of this analysis is to present safety and tolerablility data for GH001 from the double-blind part of a Phase 2b trial in which GH001 was administered as an individualized dosing regimen (IDR) to patients with TRD  Figure 1. Clinical Trial Schematic  aPatients also attended assessment visits on Day 2 (phone call) and Day 8 after each re-treatment.  BL = Baseline; D = Day; h = Hour; IDR = Individualized dosing regimen; MADRS = Montgomery-Åsberg Depression Rating Scale.  Results From the Double-Blind Part  In the double-blind part of this trial, 81 patients with TRD were enrolled; 40 and 41 patients were randomized to receive GH001 or placebo, respectively  The mean (SD) age was 42.8 (11.2) years; 56.8% of the patients were female  There were no serious or severe TEAEs reported (Table 1)  TEAEs were observed in 29/40 (72.5%) patients who received GH001 and 3/41 (7.3%) patients who received placebo (Table 1)  The maximum severity of TEAEs observed in patients who received GH001 was mild in 14/29 patients and moderate in 15/29 patients  No TEAE resulted in study drug withdrawal or early withdrawal from the trial in either treament group in the double-blind part  No TEAEs of flashbacks were reported  Table 1. Overall Summary of Safety in the Double-Blind Part  Patients, n (%)  GH001 (n=40)  Placebo (n=41)  Any TEAE  29 (72.5)  3 (7.3)  Maximum severity of TEAEs Mild  Moderate Severe  14 (35.0)  15 (37.5)  0  2 (4.9)  1 (2.4)  0  Treatment-related TEAEs 29 (72.5) 1 (2.4)  Serious TEAE 0 0  AESIs 8 (20.0) 0  Death 0 0  17 (42.5)  8 (20.0)  8 (20.0)  3 (7.5)  3 (7.5)  0  0  0  1 (2.4)  0  TEAEs occurring in >5% of patients in either group Nausea  Salivary hypersecretion Paresthesia  Headache Dysgeusia  AESI = Adverse event of special interest; TEAE = Treatment-emergent adverse event.  Of the 81 total TEAEs in the double-blind part, 80.2% of events resolved within 1 hour, 8.6% resolved within 24 hours, 7.4% resolved within 72 hours, and 1.2% resolved within 1 week  – Of the TEAEs reported at least twice in patients receiving GH001, most resolved within 1 hour of dosing (Figure 2)  Figure 2. Duration of TEAEs Reported at Least Twice After GH001 Administration in the Double-Blind Part  Total number of events  10  8  3  3  3  2  2  2  2  2  100  100  100  66.7  66.7  100  100  100  94.7  100  5.3 19  33.3  33.3  Tearfulness  Fatigue  Vomiting  Hypotonia  Cough  Headache  Memory impairment  Dysgeusia  Paresthesia  Salivary hypersecretion  Nausea  TEAE  50.0 50.0  0 10 20 30 40 50 60 70 80 90 100  Percentage of TEAEs in Duration Category  Resolved within 1 hour Resolved within 24 hours Resolved within 72 hours Resolved within 1 week  TEAE = Treatment-emergent adverse event.  There were no TEAEs related to vital signs or ECG results and no clinically significant changes in blood pressure or heart rate (Figure 3)  There was no evidence of treatment-emergent worsening of suicidal ideation or behavior (assessed by the C-SSRS), psychotic symptoms (assessed by the BPRS+), or dissociation at discharge (assessed by the CADSS)  By 1 hour postdose, no sedation was observed (assessed by the MOAA/S scale),  and 97.4% of patients were discharge-ready (1 patient was not considered discharge- ready following dosing, but after reassessment later the same day, the patient was determined to be discharge-ready)  Figure 3. Mean Heart Rate After Administration of GH001 or Placebo in the Double-Blind Part  50  60  70  80  90  100  GH001 (n=40) Placebo (n=41)  Mean (SD) Heart Rate, bpm  BL 5 10 15 20 25 30 60 5 10 15 20 25 30 60 5 10 15 20 25 30 60  Minutes after Dose 1 Minutes after Dose 2 Minutes after Dose 3  After PsE have subsided After PsE have subsided After PsE have subsided Dose 1 Dose 2 Dose 3  Discharge  BL = Baseline; bpm = Beats per minute; PsE = Psychoactive effects; SD, standard deviation.     Conclusion  The results of this analysis of the double-blind part of this Phase 2b trial demonstrated that GH001 administered as an IDR was well tolerated in patients with TRD up to 7 days postdose  References  1. Kubitz N, et al. PLoS One. 2013;8:e76882. 2. Jha MK, Mathew SJ. Am J Psychiatry. 2023;180:190-9.  3. Reckweg J, et al. Front Pharmacol. 2021;12:760671. 4. Reckweg JT, et al. Front Psychiatry. 2023;14:1133414.  Acknowledgments  This trial was sponsored by GH Research. The sponsor would like to thank the participants in the trial. The sponsor would also like to thank the investigators who conducted this trial. Under the guidance of authors, medical writing and editorial support were provided by Brian Brennan, PhD, and Claire Sweeney, PhD, of GH Research Ireland Limited, and Jane Phillips, PhD, of OPEN Health. Statistical analysis was carried out by Rachael MacIsaac, PhD, of GH Research Ireland Limited.  Disclosures  WJC: Grants – Acadia, Angelini, Beckley Psytech, GH Research, HMNC Brain Health, Intra-Cellular Therapies, Janssen, MSD, Neumora, Novartis, Otsuka, Recognify Life Sciences. Honoraria – Angelini, GH Research, Janssen, and Novartis. Advisory boards – Douglas Pharmaceuticals, GH Research, Janssen, MSD, and Novartis (relationships reported within the last three years). BTB: Consultant – National Health and Medical Research Council (Australia). Honoraria – Angelini, AstraZeneca, Biogen, BMS, Boehringer Ingelheim, Johnson & Johnson, LivaNova, Lundbeck, Medscape, Otsuka, Pfizer, Roche, Servier, Sumitomo Pharma, Sunovion, Teva, and Wyeth. Advisory boards – Biogen, Boehringer Ingelheim, Janssen-Cilag, LivaNova, Lundbeck, Medscape, Novartis, Otsuka, and Teva. Research grants from private industries or nonprofit funds – AstraZeneca, BMBF (Germany), BMG (Germany), DFG (Germany), ERA PerMed, Fay Fuller Foundation, Horizon Europe (European Union), James & Diana Ramsay Foundation (Adelaide), Johnson & Johnson, Lundbeck, La Marató de TV3, National Health and Medical Research Council (Australia), Sanofi-Synthélabo, and Wellcome Trust (UK). NC: Grants – Spanish Ministry of Health, Spanish Ministry of Science and Innovation (CIBERSAM), Strategic Plan for Health Research and Innovation (PERIS) 2016–2020, Recercaixa, and La Marató de TV3. Honoraria – Adamed, Elsevier, Exeltis, Janssen, Lundbeck, Pfizer, and Servier. Advisory Boards – Angelini, Esteve, Janssen, Lundbeck, Novartis, Pfizer, and Viatris. Lectures/Meetings – Janssen, Lundbeck, and Pfizer. RMDH: Principal investigator – Beckley Psytech and  GH Research. Subinvestigator – Compass. LJ: Principal investigator – GH Research. JRK: Principal investigator – Compass,  GH Research, and Transcend Therapeutics. Consultant – Clerkenwell Health. Grant funding – Health Research Board (ILP-POR-2022-030, DIFA-2023-005, KTA-2024-002). SJM: Principal investigator – GH Research and Transcend Therapeutics. Honoraria – Janssen and Lundbeck. AN: Principal investigator – GH Research. TP: Principal investigator –  Compass, GH Research, MAPS, and Ketabon. Shares – Psychedelická klinika s.r.o., Společnost pro podporu neurovědního výzkumu s.r.o., and AVI-X Aviation Experts s.r.o. Founder – PSYRES (Psychedelic Research Foundation). Consultant – CB21 Pharma and GH Research. AR: Honoraria for lectures and/or advisory boards – AbbVie, Boehringer Ingelheim, Cyclerion, Compass, GH Research, Janssen, LivaNova, Medice, MSD, Newron, Sage/Biogen, and Shire/Takeda. Research grants – Medice and Janssen. VPS: Consultant, honoraria, or grants – AB-Biotics, AstraZeneca, Bristol Myers Squibb, CIBERSAM, FIS-ISCiii, Janssen Cilag, Lundbeck, Medtronic, Otsuka, and Servier. MHT: Advisory boards – Alto Neuroscience and  Base Point Health Management. Consultant – Axsome, Biogen, Daiichi Sankyo, GH Research, Legion Health, Neurocrine Biosciences, Otsuka Pharmaceutical Europe, Otsuka Pharmaceutical Development & Commercialization, Otsuka Pharmaceutical, PureTech, and Takeda. Advisor – Cerebral Therapeutics, Circular Genomics, and Seaport Therapeutics. Scientific advisor – GreenLight VitalSign6. Board of Directors – Charities2Love. VV: Employee of GH Research and stock option holder. EV: Grants – AB-Biotics, AbbVie, Almirall, AstraZeneca, Boehringer Ingelheim, Bristol Myers Squibb, Celon, Cephalon, Dainippon Sumitomo Pharma, Elan, Ferrer, GH Research, GlaxoSmithKline, Janssen, Lilly, Lundbeck, Orion, Otsuka, Pfizer, Sanofi Aventis, Servier, Sunovion, and Takeda. Honoraria – Abbott, AbbVie, Angelini, AstraZeneca, Bristol Myers Squibb, Cambridge University Press, Elsevier, Farmindustria, Ferrer, Galenica, GlaxoSmithKline, Janssen, Johnson & Johnson, Lilly, Lundbeck, Oxford University Press, Otsuka, Pfizer, Sanofi Aventis, and  Viatris. Advisory boards – AbbVie, Angelini, AstraZeneca, Biogen, Biohaven, Bristol Myers Squibb, Celon, Compass, Ferrer, GH Research, Gedeon Richter, HMNC, Idorsia, Janssen, Johnson & Johnson, Jazz, Lilly, Lundbeck, Merck Sharp & Dohme, Novartis, Organon, Otsuka, Pfizer, Roche, Sage, Sanofi Aventis, Servier, Shire, Sunovion, Takeda, and Teva. MET: Grants – Acadia, Alkermes, Axsome, Intra-Cellular Therapies, Janssen, National Institute of Mental Health, Otsuka, Patient-Centered Outcomes Research Institute (PCORI), and Takeda. Advisory Boards – Autobahn Therapeutics, Axsome, Clexio Biosciences, Gerson Lehrman Group, GH Research, Lundbeck, Janssen, Johnson & Johnson, Luye Pharma, Merck, Object Pharma, Otsuka, Pfizer, Sage, Seelos Therapeutics, Sunovion, and Takeda. Royalties – American Psychiatric Association Foundation, Guilford Publications, Herald House, Wolters Kluwer, and  W W Norton & Company.  Presented at the American Society of Clinical Psychopharmacology Annual Meeting | Scottsdale, AZ, USA | May 27−30, 2025  N=81  Randomization 1:1  GH001 IDR  Day 1  Open-Label Extension (OLE)  For re-treatment (up to five GH001 IDRs), the patient must have met one of the following criteria:  MADRS score >18  MADRS score >10 and ≤18 and MADRS score ≤10 not observed at Day 8 of the prior treatment or at any visit since  MADRS score >10 and ≤18 and MADRS score >18 observed since the most recent observation of MADRS score ≤10  Primary Endpoint ΔMADRS  Day 8  During the OLE, patients attended visits at Day 15 and Months 1, 2, 3, 4, 5, and 6a Additional clinic visits could be scheduled if required for medical reasons  MADRS  assessment  Month 6  Placebo IDR  BL 2h D2  Day 2  Double-Blind Part  Patients transitioned directly from the double-blind part to the OLE

Exhibit 99.3

Results of a Phase 2a Clinical Trial of Inhaled Mebufotenin (GH001) in Patients With Postpartum Depression  Claus Bo Svendsen,1* Emilio Arbe,2 Sem E. Cohen,3 Kristina M. Deligiannidis,4 William Gann,5 Sarah Keady,1 Rachael MacIsaac,1 Stuart Ratcliffe,2 David R. Rubinow,6 Dan Tully,5 Velichka Valcheva,1 Jasper B. Zantvoord,3 Martin Johnson2  1GH Research, Dublin, Ireland; 2St. Pancras Clinical Research, London, United Kingdom; 3Department of Psychiatry, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands; 4Institute of Behavioral Science, Feinstein Institutes for Medical Research, Manhasset, New York, United States;  5Department of Psychiatry, Sheffield Health and Social Care NHS Foundation Trust, Sheffield, United Kingdom; 6Department of Psychiatry, University of North Carolina, Chapel Hill, North Carolina, United States  *Presenting Author: Claus Bo Svendsen; [email protected]  Presented at the American Society of Clinical Psychopharmacology Annual Meeting | Scottsdale, AZ, USA | May 27−30, 2025  Methods  This Phase 2a, proof-of-concept, open-label trial (NCT05804708) enrolled women aged 18–45 years who met the Mini-International Neuropsychiatric Interview diagnostic criteria for major depressive disorder with peripartum onset and who had outpatient status  Patients were required to have received no other antidepressant therapy for 14 days prior to dosing and have a Montgomery–Åsberg Depression Rating Scale (MADRS) total score of ≥28, reflecting moderate to severe depressive symptoms  Patients must have either ceased lactating at screening or, if still lactating or actively breastfeeding, must have agreed to temporarily cease breastfeeding from just prior to dosing through 24 hours after the last dose  Patients were administered an individualized dosing regimen (IDR) of up to three escalating doses of GH001 (6, 12, and 18 mg) with a 1-hour interval between doses on a single day (Figure 1)  Criteria for administration of the second and third doses as part of the IDR were based on patients’ subjectively reported psychoactive effects and the safety and tolerability at the previous dose level  Background  •  •  Postpartum depression (PPD) is a common perinatal complication that can have serious consequences for the well-being of the mother and the long-term development of the child1,2  Epidemiologic studies estimate the global prevalence rate of PPD to be as high as 20%,3 with up to 13% of diagnosed patients still experiencing symptoms two years after giving birth4  Current treatment options for PPD have slow onset of action, low remission rates, and/or high treatment burden5; therefore, novel treatment methods are needed  Mebufotenin (5-methoxy-N,N-dimethyltryptamine [5-MeO-DMT]) is a potent psychedelic drug that acts as a non-selective serotonin agonist  with highest affinity for the 5-HT receptor subtype6  •  1A  Early-phase clinical trials of mebufotenin administered via pulmonary inhalation (GH001) demonstrated that GH001 has an acceptable safety profile and is well tolerated, with an ultra-rapid onset of therapeutic benefits7,8  The trial presented here is the first in which mebufotenin was administered to patients diagnosed with PPD  Objective  To investigate the potential antidepressant effects and safety of GH001 in adult, female patients with PPD  Results  This trial enrolled 10 patients diagnosed with PPD with a mean (SD) age of 32 (5.2) years  The mean (SD) duration of the current depressive episode was 30.9 (12.9) weeks, and the mean (SD) parity was 2 (0.94)  One patient (10.0%) had received pharmacotherapy for the current depressive episode, and six patients (60.0%) had received pharmacotherapy for prior major depressive episodes  The mean (SD) baseline MADRS total score was 36.7 (4.8)  Efficacy  The primary endpoint was achieved, with a significant reduction from baseline to Day 8 of  −35.4 points (96.3%) in MADRS total score with GH001 treatment (P<0.0001; Figure 2)  Significant reductions in MADRS total score were also observed at 2 hours postdose and on Day 2 (P<0.0001 for both time points)  All 10 patients demonstrated nearly identical and consistent reductions in MADRS total score at 2 hours postdose, on Day 2, and Day 8 (Figure 3)  All patients (100%) achieved remission at Day 8, as well as at 2 hours postdose and on Day 2  Figure 2. Mean Change in MADRS Total Score From Baseline in Patients With PPD Treated With GH001  BL = Baseline; MADRS = Montgomery-Åsberg Depression Rating Scale; PPD = Postpartum depression; SD, standard deviation.  Figure 3. MADRS Total Scores for Individual Patients With PPD Treated With GH001  BL = Baseline; MADRS = Montgomery-Åsberg Depression Rating Scale; PPD = Postpartum depression.  Safety  TEAEs were observed in 8/10 patients (80.0%) and were mostly mild in severity (87.5%); only one patient reported a TEAE as moderate in severity  Headache was the most commonly reported TEAE (5/10 patients); all other TEAEs occurred in a single patient each  No TEAEs of flashbacks were reported  There were no serious TEAEs or severe TEAEs, and no patient withdrew from the trial  There was a clinically significant reduction in BPRS from baseline to Day 8 (−23.7)  There was no clinically relevant worsening of other clinician-rated assessments (based on the CADR, C-SSRS, and MOAA/S scales)  Based on the CADR, all patients were deemed ready for discharge within the same day of dosing  Table 1. Summary of Safety in Patients With PPD Treated With GH001 (N=10)  Patients, n (%)  Any TEAE  8 (80.0)  Mild  7 (87.5)  Moderate  1 (12.5)  Severe  0  Treatment-related TEAEs  7 (70.0)  Serious TEAE  0  Death  0  TEAEs by Preferred Term  Headache  5 (50.0)  Abdominal pain  1 (10.0)  Nausea  1 (10.0)  Vomiting  1 (10.0)  Diarrhea  1 (10.0)  Dizziness  1 (10.0)  Dysgeusia  1 (10.0)  Tachycardia  1 (10.0)  Paresthesia  1 (10.0)  PPD = Postpartum depression; TEAE = Treatment-emergent adverse event.  Conclusions  In this trial evaluating the safety and antidepressant effects of GH001 in patients with PPD, the primary endpoint was met: a significant reduction from baseline in MADRS total score was observed on Day 8 postdose  Significant reductions in MADRS total score were observed by 2 hours postdose, confirming an ultra-rapid antidepressant effect of GH001  GH001 administered via inhalation demonstrated a favorable safety profile and was well tolerated in patients with PPD; no serious TEAEs were reported  This trial was conducted under the supervision of qualified healthcare professionals, providing psychological support per standard of care, but without any planned psychotherapeutic intervention before, during, or after dosing  The primary endpoint was change in MADRS total score from baseline to Day 8; change from baseline in MADRS total score at 2 hours and Day 2 postdose and MADRS remission (MADRS total score ≤10) were assessed as secondary endpoints  Safety and tolerability were assessed throughout the trial as secondary endpoints and included the following parameters: treatment-emergent adverse events (TEAEs), sedation as assessed by the Modified Observer’s Assessment of Alertness and Sedation (MOAA/S), psychiatric symptoms as assessed by the Brief Psychiatric Rating Scale (BPRS), and suicidality as assessed by the Columbia-Suicide Severity Rating Scale (C-SSRS)  Discharge readiness was assessed by the Clinical Assessment of Discharge Readiness (CADR)  P values were calculated using one-sample t tests with a one-sided significance level of α=0.025, and the study was adequately powered to detect a clinically meaningful difference  Figure 1. Clinical Trial Design  D = Day; IDR = Individualized dosing regimen; MADRS = Montgomery-Åsberg Depression Rating Scale; PPD = Postpartum depression.  End of trial  MADRS  Safety  D8  D−60 to D−2  D−1  Follow up  MADRS  Safety  Single-day IDR  D1 D2  Patients with PPD N=10  1-hour interval  1-hour interval  Key Screening Pre-dosing GH001 IDR Assessments day MADRS  Safety  Dose 3  18 mg GH001  Dose 2  12 mg GH001  Dose 1  6 mg GH001  5  0  50  45  40  35  30  25  20  15  10  MADRS Total Score  Remission (MADRS ≤10)  Time Postdose  Day 8  Day 2  BL  2 Hours  0  −31.4  −36.0  −35.4  -45  -40  -35  -15  -20  -25  -30  -5  -10  0  Mean (SD) Change in MADRS Total Score From BL  ***  ***  ***  Time Postdose  ***P<0.0001 vs BL  Day 8  Day 2  BL  2 Hours  References  Stewart DE, Vigod S. N Engl J Med. 2016;375:2177-86.  Field T. Infant Behav Dev. 2010;33:1-6.  Wang Z, et al. Transl Psychiatry. 2021;11:543.  Goodman JH. J Obstet Gynecol Neonatal Nurs. 2004;33:410-20.  Kaufman Y, et al. Ther Adv Psychopharmacol. 2022;12:20451253211065859.  Ermakova AO, et al. J Psychopharmacol. 2022;36:273-94.  Reckweg J, et al. Front Pharmacol. 2021;12:760671.  Reckweg JT, et al. Front Psychiatry. 2023;14:1133414.  Acknowledgments  This trial was sponsored by GH Research. The sponsor would like to thank the participants in the trial. The sponsor would also like to thank the investigators who conducted this trial. Under the guidance of authors, medical writing and editorial support were provided by Brian Brennan, PhD, and Claire Sweeney, PhD, of GH Research Ireland Limited, and Jane Phillips, PhD, of OPEN Health.  Disclosures  CBS: Consultant to and shareholder of GH Research. EA, SEC, WG, DT, JBZ, and MJ: Nothing to disclose. KMD: Consultant − Biogen, Brii Biosciences, Gerbera Therapeutics, GH Research, Neurocentria, Reunion Neuroscience, and Sage. Principal investigator for contracted research − DuKang Pharmaceuticals, Sage, and Woebot Health. SK, RM, and VV: Employees and stock option holders of GH Research. SR: Consultant − Grünenthal, Actinogen, Takeda, GSK, GW Pharma, Astra Zeneca, Camurus, Cleothena, and Ipsen. DRR: Research funding − NIH, Baszucki Foundation, and Sage. Scientific advisory board − Sage and Sensorium. Clinical advisory board − Felicitypharma and Embarkneuro. Consultant − Brii Biosciences, GH Research, and Aldeyra Therapeutics.