GH Research PLC (Nasdaq: GHRS) August 2026 1 2026© GH Research
PLC Ultra-Rapid, Durable Remission in TRD
Any statements contained herein that do not describe historical facts are
forward-looking statements that are based on management’s expectations and are subject to certain factors, risks and uncertainties that may cause actual results, outcomes, timing and performance to differ materially from those expressed or
implied by such statements. These factors, risks and uncertainties include, but are not limited to: the costs and uncertainties associated with GH Research’s research and development efforts; the inherent uncertainties associated with the
conduct, timing and results of nonclinical and clinical studies of GH Research’s product candidates; GH Research’s expectations related to commencing trials in the US; GH Research’s ability to obtain, maintain, enforce and defend issued
patents; the adequacy of GH Research’s capital resources, the availability of additional funding and GH Research’s cash runway; and other factors, risks and uncertainties described in GH Research’s filings with the U.S. Securities and Exchange
Commission. Except as otherwise noted, these forward-looking statements speak only as of the date of this presentation, and GH Research undertakes no obligation to update or revise any of such statements to reflect events or circumstances
occurring after this presentation. Because forward-looking statements are inherently subject to risks and uncertainties, some of which cannot be predicted or quantified and some of which are beyond GH Research’s control, you should not rely on
these forward-looking statements as predictions of future events. The events and circumstances reflected in any such forward-looking statements may not be achieved or occur and actual results could differ materially from those projected in the
forward-looking statements. GH Research cautions you not to place undue reliance on the forward-looking statements contained in this presentation. 2026© GH Research PLC This presentation has been prepared by GH Research PLC (“GH Research”).
Nothing contained in this presentation is, or should be construed as, a recommendation, promise or representation by the presenter or GH Research or any director, employee, agent, or adviser of GH Research. This presentation does not purport to
be all-inclusive or to contain all of the information you may desire. This presentation does not constitute an offer to sell or the solicitation of an offer to buy securities, nor shall there be any sale of securities in any state or
jurisdiction in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such state or jurisdiction. This presentation contains forward-looking statements, all of which
are qualified in their entirety by this cautionary statement. Many of the forward-looking statements contained herein can be identified by the use of forward-looking words such as “may”, “anticipate”, “believe”, “could”, “expect”, “should”,
“plan”, “intend”, “estimate”, “will”, “potential” and “ongoing”, among others, although not all forward-looking statements contain these identifying words. Disclaimer Regarding Forward-Looking Statements 2
GH Research at a glance 1 Post-Phase 2b: shortest-acting psychedelic with
category-defining TRD data ~11 min psychoactive phase; 57.5% Day 8 remission and 73% at 6 months in OLE completers 2 Spravato-compatible clinic model — GH001 only option with up to 3 treatments per visit Fits Spravato established existing
interventional infrastructure, with 83% visit reduction 3 Strong IP estate + NCE-style regulatory exclusivity Patent runway into the 2040s, multi-layer protection, and a high technical bar for inhaled systemic generics 4 ~$362.7m cash —
next step, execute Phase 3 Balance sheet strength de-risks the path from positive Phase 2b to registration studies Abbreviations: TRD = Treatment-Resistant Depression; min = Minute; OLE = Open-Label Extension; IP = Intellectual Property; NCE
= New Chemical Entity Cash figure as of June 30, 2026 (cash, cash equivalents and marketable securities). Clinical data from GH001 TRD Phase 2b / OLE; visit comparison is cross-trial vs Spravato model (not head-to-head). Sources as cited
throughout. 2026© GH Research PLC 3
~4m Patients with TRD in the USa 37% Step 1 0 failures 31% Step 2 1
failure 14% Step 3 2 failures 13% Step 4 3 failures TRD population ~1 in 3 have a lifetime suicide attempt4 ~75% live with anhedonia or constant anxiety5,6 2× worse quality of life vs MDD6 Abbreviations: TRD = Treatment-resistant
depression; US = United States of America; MDD = Major Depressive Disorder; STAR*D = Sequenced Treatment Alternatives to Relieve Depression. Notes: a. Company estimates based on sources 1,2,3 Sources: 1. NIMH major depression statistics; 2.
Wittchen et al., Eur Neuropsychopharmacol 2011; 3. Rush AJ et al,. Am J Psychiatry. 2006;163(11):1905-1917; 4. Bergfeld et al. J Affect Disord. 2018;235:362-367; 5. McIntyre et al., World Psychiatry 2023, 22(3):394-412.; 6. Jaffe DH, Rive B,
Denee TR. BMC Psychiatry, 2019;19(1):247. >85% of TRD patients FAIL to remit after two or more failed therapies3 STAR*D, Remission rate (%) by prior treatment failures3 TRD is prevalent and debilitating — remission collapses after two
failures 2026© GH Research PLC 4
Product Candidate Indication Preclinical Phase 1 Phase 2a Phase 2b Phase
3 Current Status Milestone GH001 Mebufotenin for inhalation administration Treatment-resistant depression (TRD) Phase 2b RDBPC completed Phase 3 initiation in 2026 Postpartum depression (PPD) Phase 2a POC Completed Bipolar II
Disordera (BDII) Phase 2a POC Completed GH002 Mebufotenin for i.v. administration Psychiatric disorder Phase 1 HV trial completed IND submission Pipeline Cash, cash equivalents and marketable securities were $362.7 million as of June
30, 2026 Completed In Planning Abbreviations: HV = Healthy volunteer; IND = Investigational New Drug; i.v. = Intravenous; POC = Proof-of-concept; RDBPC = Randomized, double-blind, placebo-controlled. aBipolar II disorder with a current
major depressive episode. 2026© GH Research PLC 5
Abbreviations: BL = Baseline; FDA = Food and Drug Administration; H = Hours; LS =
Least squares; MADRS = Montgomery-Åsberg Depression Rating Scale; SE = Standard error. Sources & Notes: 1: FDA Guidance notes that efficacy with rapid-acting antidepressants generally should be demonstrated within 1 week, supporting a
primary efficacy endpoint within this timeframe. FDA Guidance: Major Depressive Disorder: Developing Drugs for Treatment. https://www.fda.gov/media/113988/download. Accessed on 26 June 2025; 2: Cubała WJ et al., JAMA Psychiatry. 2026;
doi:10.1001/jamapsychiatry.2026.009 −17.8 −18.6 −15.2 −1.4 −1.5 0.3 -25 -20 -10 -15 -5 0 LS mean difference vs placebo: −15.5 (P<0.0001) Effect size: Cohen’s d = −2.0 LS Mean (±SE) Change from Baseline in MADRS Total
Score BL 2H Day 2 Day 8 GH001 (n=40) Placebo (n=41) Phase 2b Study Primary Endpoint: GH001 Led to Mean MADRS Reduction from Baseline of -15.5 on Day 81 vs Placebo (P<0.0001)2 2026© GH Research PLC 6
70.0% 57.5% 4.9% 0.0% 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% Percentage
of patients in remission 15.1% 10.1% 21.3% 10.3% 5.3% 6.5% 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% Percentage of patients in remission Remission Rates with GH0011 Day 2 Day 8 Day 2 Day 8 Day 28 Remission Rates with
Spravato monotherapy (84mg) from TRD40052,b Secondary Endpoints: Remissionsa GH001 Day 2 and Day 8 and Spravato Monotherapy (84 mg) Day 2, Day 8 and Day 28 GH001 Placebo Spravato Placebo Abbreviations: MADRS = Montgomery-Åsberg Depression
Rating Scale Notes: To-date, no head-to-head comparisons of any other products to any of our product candidates in any clinical trial have been completed; results have been obtained from different trials with different designs, endpoints and
patient populations; results may not be comparable. a. Remission defined as MADRS total score ≤10 for both GH001 and Spravato; b. Spravato 56mg participants in the TRD4005 trial achieved remission rates of 13.1% at Day 2, 7.1% at Day 8 and
14.6% at Day 28 (MADRS ≤10) Sources: 1. Cubała WJ et al., JAMA Psychiatry. 2026;83(6):561-569; 2. Spravato monotherapy data for 84mg dose from TRD4005 trial, Janik et al. 2025. 2026© GH Research PLC 7
73% Remission Rate at 6 Months in OLE Completers1 Abbreviations: MADRS =
Montgomery-Åsberg Depression Rating Scale; OLE = Open-label extension. Notes: a. Includes 63 patients who completed the 6-month OLE per protocol (18 patients terminated early are excluded). b. Approximately 6 months post-study start (median
168 days from Day 1 of double-blind part). c. Remission defined as MADRS total score ≤10. Sources : 1: Cubała WJ et al., JAMA Psychiatry. 2026; doi:10.1001/jamapsychiatry.2026.009 57.5% 0 20 40 60 80 100 Double-blind n=40 on
GH001 OLE completersa n=63 Day 8 Percentage of Patients in Remissionc Patients who completed the OLE had a mean of four treatment visits, with 63.5% (40/63) requiring one to four treatment visits during the 6 months 73.0% Month
6ᵇ 2026© GH Research PLC 8
GH001 demonstrates efficacy independent of prior treatment lines in
TRD1 n=7 n=13 n=8 n=11 n=7 n=13 n=8 n=11 Progressive Attenuation Mean Mean GH001 remission rates remain consistent (Day 8 ~60%) across all treatment-resistance categories, in direct contrast to STAR*D progressive decline (37% →
13%) Abbreviations: TRD = Treatment-Resistant Depression; MADRS = Montgomery-Åsberg Depression Rating Scale; STAR*D = Sequenced Treatment Alternatives to Relieve Depression. Sources : 1. Thase ME et al., 2026. Psychopharmacology Bulletin,
56(3): 8-21.; 2. Rush AJ et al,. Am J Psychiatry. 2006;163(11):1905-1917. 2026© GH Research PLC 9
GH001 is Built for the Interventional Psychiatry
Workflow SPRAVATO®1,2 GH0013 Setting Outpatient clinics by qHCPs and clinical staff Outpatient clinics by qHCPs and clinical staff Psychotherapy No mandated psychotherapy No mandated psychotherapy Psychoactive phase ~1.5 hours ~11
minutes Clinic visit ~2 hours ~1–3 hoursa Treatments per visit 1 per visit Up to 3 per visit SPRAVATO® = esketamine nasal spray. qHCP = qualified healthcare provider. Notes: a. Clinic visit reflects expected time-to-discharge; GH001 may
use 1–3 doses. Sources: 1. SPRAVATO FDA full prescribing information; 2. Spravato dissociation lasts ~90 minutes, peak effects at 40 minutes (Popova V, et al. Am J Psychiatry 2019; 176:428–438).; 3. GH001 TRD Ph2b data, Cubała et al., JAMA
Psychiatry 2026. WHERE GH001 DIFFERS 2026© GH Research PLC 10
GH001: Shortest Duration of the Psychoactive Experience of 11 minutes — enables up
to 3 treatments per clinic visit Abbreviations: h = Hours; min = Minutes; OLE = Open-label extension; SDI = Subjective drug intensity; SIRS = Subjective Intensity Rating Scale; TRD = Treatment-resistant depression. Note: To-date, no
head-to-head comparisons of any other products to any of our product candidates have been completed in any clinical trial; results have been obtained from different trials with different designs, endpoints, and patient populations; results may
not be comparable. a. Spravato dissociation lasts ~90 minutes, peak effects at 40 minutes (Popova V, et al. Am J Psychiatry 2019; 176:428–438); b. Assumption of BPL-003 duration of ~90min psychoactive phase from Phase 1 SDI results as reported
in Rucker et al., 2024; c. VLS-01 duration of 90-120 minutes psychoactive experience from Phase 1b results (AtaiBeckley Corporate Presentation, May 2026). d. COMP360 duration of 6-8h from Goodwin et al., N Engl J Med 2022;387:1637-1648.
d.. 0 2h Duration of Psychoactive Experience (approximate average) within 90 min 90-120 min 7h 6h 5h 4h 3h 6-8 hours 8h 2026© GH Research PLC 1h GH001 SPRAVATO®a BPL-003b VLS-01c COMP360d 11 min (median) ~90 min 11
GH001: Only psychedelic with 1-3 treatments for highest efficacy and fast
relief TREATMENT(S) WITHIN VISIT Not forced uptitration — stop when ready. DAY 8 REMISSION GH001 57.5% BPL-003 26.0% 8mg (core Ph2b study) Abbreviations: h = Hour; min = Minute Note: To-date, no head-to-head comparisons of any other
products to any of our product candidates have been completed in any clinical trial; results have been obtained from different trials with different designs, endpoints, and patient populations; results may not be comparable Sources: Cubala et
al. JAMA Psychiatry 2026; SPRAVATO FDA Full Prescribing Information; Spravato monotherapy data for 84mg dose from TRD4005 trial, Janik et al. 2025; BPL-003 phase 2b data from AtaiBeckley Corporate Presentation, May 2026. CLINIC
FOOTPRINT GH001 1–3 h 99% discharge-ready ≤1 h after last dose SPRAVATO 2 h REMS 2h post-dose monitoring → All target the interventional treatment slot GH001 1-3 Treatments per visit 75% reach target intensity in 1–2 doses. SPRAVATO
monotherapy 10.1% BPL-003 ~2 h Median ~98 min to discharge-ready BPL-003 Only 1 possible SPRAVATO Only 1 possible 84mg 8mg selected for Ph3 56mg or 84mg based on efficacy & tolerability Phase 2b study Cross-trial; not
head-to-head 2026© GH Research PLC 12
0 5 20 25 GH001 10 15 Treatment visits in 6 months 23 visits ICER
estimateᶜ,ᵈ 83% Fewer Treatment Visits with GH001 than with Spravato® Four visitsa 73% remission at 6 monthsb,d SPRAVATO® 2026© GH Research PLC Abbreviations: ICER = Institute for Clinical and Economic Review; LOCF = Last observation
carried forward; MADRS = Montgomery-Åsberg Depression Rating Scale; OLE = Open-label extension; TRD = Treatment-resistant depression. Notes: To-date, no head-to-head comparisons of any other products to any of our product candidates have been
completed in any clinical trial; results have been obtained from different trials with different designs, endpoints, and patient populations; results may not be comparable. a. Four GH001 visits deduced from the mean total number of treatments
received by patients who completed the OLE and were in remission at 6-months of the GH001-TRD-201 trial.; b. 6 months’ (end of trial) was at approximately 6 months post-study start (median 168 days from Day 1 of double-blind part); c. SPRAVATO®
Assumes 23 treatment visits, as per standard initiation protocol of eight and four sessions in Months 1 and 2, respectively, and ICER assumed maintenance treatment frequency of 2.86 treatments per month for Months 3-6.1,2,3; d. Remission
defined as MADRS ≤10; Spravato® 32-Week remission rates from ESCAPE-TRD trial were 49.1% remission at 32 weeks (55.0% with LOCF method)4. Sources: 1. Johnson & Johnson Spravato Access, Coding and Reimbursement Guide. 2. ICER Spravato®
Final Evidence Report. 3. Janssenscience.com, Dosage and Administration of Spravato, Duration of Therapy. 4. Reif et al. New Engl J Med 2023. 4 vs 23 · ~6× fewer 13
Beyond MADRS: Rapid and Durable Multi-Domain Benefit in TRD Abbreviations: TRD =
Treatment-Resistant Depression; MADRS = Montgomery-Åsberg Depression Rating Scale; HAM-A = Hamilton Anxiety Rating Scale; LS = Least Squares; CGI-S = Clinical Global Impression – Severity Sources: Data from the GH001 TRD Ph2b trial, Cubała WJ
et al., JAMA Psychiatry. 2026; doi:10.1001/jamapsychiatry.2026.009; Cubala WJ et al., ASCP 2026. LS Mean Change From Baseline GH001 (n=40) Placebo (n=41) CGI-S Score HAM-A Total Score −2.5 points greater reduction vs placebo,
P<0.0001 6 - Severely ill 5 - Markedly ill 4 - Moderately ill 3 - Mildly ill 2 - Borderline ill 1 - Normal OLE completers (n=63) −3.0 Mean change from Baseline, P<0.0001 GH001 (n=40) Placebo (n=41) OLE completers
(n=63) Day 8 Month 6 Day 8 Month 6 **** **** **** = P<0.0001 2026© GH Research PLC 14
Mean (±SD) Change from Baseline in MADRS Anhedonia Factor
Score BL D1 D2 D8 MCICa **** **** **** MADRS Anhedonia Factor Score Abbreviations: TRD = Treatment-Resistant Depression; MADRS = Montgomery-Åsberg Depression Rating Scale; SD = Standard Deviation; OLE = Open-Label Extension; MCIC =
Minimal clinically important change; LS = Least Squares; Q-LES-Q-SF = Quality of Life Enjoyment and Satisfaction Questionnaire – Short Form aClinically meaningful improvement in MADRS anhedonia factor has been reported as an MCIC of –4.6 to
–5.5 points based on an analysis of patients with MDD (McIntyre RS. J Affect Disord. 2024;363:430-435) Sources: Data from the GH001 TRD Ph2b trial, Cubała WJ et al., JAMA Psychiatry. 2026; doi:10.1001/jamapsychiatry.2026.009; Cubala WJ et al.,
ASCP 2026; McIntyre et al., ASCP 2026. Q-LES-Q-SF Total Score Day 8 Month 6 Month 6 **** OLE completers (n=63) Day 8 Month 6 **** **** **** = P<0.0001 OLE — no placebo arm 2026© GH Research PLC 15 Beyond MADRS: Anhedonia and
Quality of Life Benefit in TRD
Rapid MADRS response across TRD, PPD, and BDII + MDE Abbreviations: BDII =
Bipolar II disorder; BL = Baseline; D = Day; MADRS = Montgomery–Åsberg Depression Rating Scale; MCIC = Minimal clinically important change; MDD = Major depressive disorder; MDE = Major depressive episode; OLE = Open-label extension; PPD =
Postpartum depression; TRD = Treatment-resistant depression. aClinically-meaningful improvement in depression, defined as a 1-point CGI-S score change, corresponded to a –6 point change in MADRS total score in an analysis of patients with TRD
on Esketamine treatment4 Sources: 1. Cubala et al., JAMA Psychiatry 2026; 2. Johnson M et al. J of Clin Psych. 2026;87(3):25m16284. 3. Reif A et al. ACNP 2026. 4. Turkoz et al. Acta Psychiatr Scand. 2021 Jan 22; 143(3):253–263 Mean (±SD)
Change From Baseline in MADRS Total Score BL D1 D2 D8 BL D1 D2 D8 BL D1 D2 D8 TRD1 PPD2 BDII + MDE3 MCIC for MADRS Total Scorea 57.5% remission at Day 8 100% remission at Day 8 33.3% remission at Day 8 2026© GH Research
PLC 16
Double-Blind Part Open-Label Extension GH001 (n=40) Placebo (n=41) GH001
(n=81) Treatment-Emergent Adverse Event Patients, n (%) Patients, n (%) Patients, n (%) Any TEAE 29 (72.5) 3 (7.3) 72 (88.9) Mild 14 (35.0) 2 (4.9) 28 (34.6) Moderate 15 (37.5) 1 (2.4) 42 (51.9) Severe 0 (0) 0 (0) 2
(2.5) Treatment-related TEAEs 29 (72.5) 1 (2.4) 65 (80.2) Treatment-related serious TEAEs 0 (0) 0 (0) 0 (0) TEAEs leading to discontinuation 0 (0) 0 (0) 1 (1.2) GH001-TRD-201 Study GH001 (n=6) Treatment-Emergent Adverse
Event Event No. Patients n (%) Any TEAE 18 5 (83.3) Mild 15 5 (83.3) Moderate 2 2 (33.3) Severe 1 1 (16.7) Treatment-related TEAEs 18 5 (83.3) Treatment-related serious TEAEs 0 0 TEAEs leading to
discontinuation 0 0 GH001-BD-202 Study GH001-PPD-203 Study GH001 (n=10) Treatment-Emergent Adverse Event Event No. Patients n (%) Any TEAE 13 8 (80.0) Mild 12 7 (70.0) Moderate 1 1 (10.0) Severe 0 0 Treatment-related
TEAEs 11 7 (70.0) Treatment-related serious TEAEs 0 0 TEAEs leading to discontinuation 0 0 GH001 was well-tolerated in patients with TRD, BDII + MDE, and PPD Abbreviations: TRD = Treatment-Resistant Depression; BDII + MDE = Bipolar II
disorder with a current Major Depressive Episode; PPD = Postpartum Depression; TEAE = Treatment-Emergent Adverse Event; Sources: 1. Cubala et al., JAMA Psychiatry 2026; 2. Johnson M et al. J of Clin Psych. 2026;87(3):25m16284. 3. Reif A et
al. ACNP 2026. 2026© GH Research PLC 17
Multi-layer IP and regulatory protection into the 2040s REGULATORY
EXCLUSIVITY FDA 5 years +2.5 years paragraph IV stay EMA 10 years +1 year for a new indication PATENTS Earliest patent filings relating to mebufotenin (including pending applications): Novel aerosol compositions of matter EARLIEST
EXPIRY 2041 Novel uses in various disorders EARLIEST EXPIRY 2040 Novel device-related aspects EARLIEST EXPIRY 2044 Novel salt forms and formulations EARLIEST EXPIRY 2043 TECHNICAL Complex bioequivalence for systemically acting
inhalation products High intra- and inter-subject PK variability raises the bar for generics Device + formulation + dosing regimen create a multi-component BE challenge Abbreviations: IP = Intellectual Property; EMA = European Medicines
Agency; FDA = Food and Drug Administration; PK = Pharmacokinetics; BE = Bio-equivalence. Patent dates are earliest expiry among relevant families; status includes granted and pending filings as applicable. 2026© GH Research PLC 18
GH Research at a glance 1 Post-Phase 2b: shortest-acting psychedelic with
category-defining TRD data ~11 min psychoactive phase; 57.5% Day 8 remission and 73% at 6 months in OLE completers 2 Spravato-compatible clinic model — GH001 only option with up to 3 treatments per visit Fits Spravato established existing
interventional infrastructure, with 83% visit reduction 3 Strong IP estate + NCE-style regulatory exclusivity Patent runway into the 2040s, multi-layer protection, and a high technical bar for inhaled systemic generics 4 ~$362.7m cash —
next step, execute Phase 3 Balance sheet strength de-risks the path from positive Phase 2b to registration studies Abbreviations: TRD = Treatment-Resistant Depression; min = Minute; OLE = Open-Label Extension; IP = Intellectual Property; NCE
= New Chemical Entity Cash figure as of June 30, 2026 (cash, cash equivalents and marketable securities). Clinical data from GH001 TRD Phase 2b / OLE; visit comparison is cross-trial vs Spravato model (not head-to-head). Sources as cited
throughout. 19 2026© GH Research PLC