GH Research (NASDAQ: GHRS) highlights Phase 2 GH001 results in postpartum and treatment-resistant depression
Filing Impact
Filing Sentiment
Form Type
6-K
Rhea-AI Filing Summary
GH Research PLC reported new clinical milestones for its inhaled mebufotenin candidate GH001 in mood disorders. The company highlighted publication of full Phase 2a results in postpartum depression, where 10 adult women received a single-day inhaled treatment and all achieved rapid remission within hours, sustained through Day 8 with a favorable safety profile and brief breastfeeding interruption.
The company also announced two oral presentations at the CINP 2026 congress, featuring Phase 2b data in treatment-resistant depression. In that trial, the primary endpoint was met, with a MADRS score reduction from baseline of -15.5 points versus placebo on Day 8 (P<0.0001), supporting continued development in depression indications.
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Insights
Encouraging mid-stage depression data, but based on small early trials.
GH Research is advancing GH001, an inhaled mebufotenin therapy, with Phase 2a postpartum depression and Phase 2b treatment-resistant depression data now highlighted. The postpartum study enrolled 10 women, all achieving rapid remission after a single treatment day, and was published in a leading psychiatry journal.
The depression program’s backbone is the Phase 2b TRD trial, where the primary endpoint was met and MADRS scores improved by -15.5 points versus placebo on Day 8 (P<0.0001). This suggests robust signal detection in a controlled setting, but larger, confirmatory trials will be needed before regulators can assess risk–benefit.
The company explicitly notes that small, open-label proof-of-concept results in postpartum depression may not translate into later-stage studies, and lists timing, enrollment, regulatory, and societal-perception risks. Future randomized, placebo-controlled trials and long-term safety data will be key for understanding GH001’s potential in depression treatment.
Key Figures
Phase 2a PPD enrollment: 10 patients
MADRS improvement vs placebo: -15.5 points
Statistical significance: P<0.0001
+3 more
6 metrics
Phase 2a PPD enrollment
10 patients
Adult women with postpartum depression in single-arm open-label trial
MADRS improvement vs placebo
-15.5 points
Phase 2b GH001-TRD-201 primary endpoint on Day 8
Statistical significance
P<0.0001
Difference in MADRS reduction vs placebo on Day 8 in TRD
CINP 2026 dates
June 26–29, 2026
World Congress of Neuropsychopharmacology in Glasgow, United Kingdom
Oral presentation slot 1
June 27, 2026, 12:30–12:45 BST
Rapid antidepressant effects of inhaled GH001 in TRD
Oral presentation slot 2
June 28, 2026, 12:15–12:30 BST
Safety and tolerability results for GH001 in TRD
Key Terms
postpartum depression, treatment-resistant depression, Phase 2a open-label clinical trial, Phase 2b, double-blind, randomized controlled trial, +2 more
6 terms
postpartum depression medical
"Phase 2a trial in postpartum depression (PPD) with inhaled mebufotenin (GH001)"
A mood disorder that can arise after childbirth, characterized by persistent sadness, anxiety, exhaustion and difficulty caring for oneself or a baby; it can range from moderate to severe and often requires medical or therapeutic treatment. Investors care because its prevalence affects demand for medical treatments, mental-health services and parental workplace policies, and can influence healthcare spending, drug development programs, and productivity in sectors that depend on caregiver labor — much like a widespread recurring expense that changes consumer and employer behavior.
treatment-resistant depression medical
"Phase 2b GH001-TRD-201 trial of GH001 in treatment-resistant depression (TRD)"
A form of major depression that does not improve after a person has tried standard treatments such as common antidepressant medications and therapy; think of it as a stubborn problem that doesn’t respond to the usual fixes. It matters to investors because it represents a large unmet medical need and a higher-risk, higher-reward area for drug developers, with potential for premium pricing, regulatory scrutiny, and durable demand if an effective new therapy is approved.
Phase 2a open-label clinical trial medical
"A Phase 2a open-label clinical trial enrolled 10 adult women with PPD"
Phase 2b, double-blind, randomized controlled trial medical
"Results from a Phase 2b, double-blind, randomized controlled trial with 6-month follow-up"
MADRS reduction medical
"Primary endpoint was met with a MADRS reduction from baseline of -15.5 points"
forward-looking statements regulatory
"This press release contains statements that are, or may be deemed to be, forward-looking statements"
Forward-looking statements are predictions or plans that companies share about what they expect to happen in the future, like estimating sales or profits. They matter because they help investors understand a company's outlook, but since they are based on guesses and assumptions, they can sometimes be wrong.
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 June, 2026.
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:
| Form 20-F | ☒ | Form 40-F | ☐ |
INFORMATION CONTAINED IN THIS REPORT ON FORM 6-K
On June 04, 2026, GH Research PLC (the “Company”) announced the publication of the full results from its Phase 2a trial in postpartum depression (PPD) and the acceptance of two oral presentations at the 37th World Congress of
Neuropsychopharmacology (CINP 2026).
A copy of the press release is exhibited hereto as Exhibit 99.1.
The fact that this press release is being made available and furnished herewith should not be deemed an admission as to the materiality of any information contained in the press release. The information contained in
the press release is being provided as of June 04, 2026, and the Company does not undertake any obligation to update the press release in the future or to update forward-looking statements to reflect subsequent actual results.
EXHIBIT INDEX
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Exhibit No.
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Description
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99.1
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Press Release dated June 04, 2026
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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.
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GH Research PLC
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| Date: June 04, 2026 | ||
| By: | /s/ Julie Ryan | |
| Name: | Julie Ryan | |
| Title: | Vice President, Finance | |
Exhibit 99.1
GH Research Announces Publication of Phase 2a Postpartum Depression Results
Dublin, Ireland, June 4, 2026 – GH Research PLC (Nasdaq: GHRS) today announced the publication of the full results from its Phase 2a trial in postpartum depression (PPD) and
the acceptance of two oral presentations at the 37th World Congress of Neuropsychopharmacology (CINP 2026).
The peer-reviewed article, titled “Inhaled Mebufotenin (GH001) for Adult Patients with Postpartum Depression: A Phase 2a Open-Label Clinical Trial,” has been published in The Journal of Clinical Psychiatry
(DOI: 10.4088/JCP.25m16284). The article reports the full results from the Phase 2a, single-arm, open-label trial, which enrolled 10 adult women with PPD. Key results:
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Primary endpoint met: Mean Montgomery–Åsberg Depression Rating Scale (MADRS) reduction of -35.4 points from baseline to Day 8 (P<0.0001)
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100% of patients (10/10) achieved remission (MADRS total score ≤10) within two hours of dosing, sustained through Day 8
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Improved maternal functioning: Mean 34.1-point (56%) increase on the Barkin Index of Maternal Functioning at Day 8
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Well-tolerated: No serious adverse events; all treatment-emergent adverse events mild or moderate; no treatment-emergent suicidal ideation or behavior
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An analysis of breast milk supports a treatment strategy with only a brief interruption of breastfeeding around GH001 dosing
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“To our knowledge, this is the first published clinical trial of a psychedelic-based therapeutic specifically in postpartum depression, and the rapid remission achieved by all patients within hours of a single-day
inhaled treatment, sustained through Day 8 with a favorable safety profile and only brief interruption of breastfeeding, is encouraging for a population that needs additional rapid-acting therapeutic options. These findings support further
investigation of inhaled mebufotenin in larger, randomized, placebo-controlled trials in postpartum depression,” said Kristina M. Deligiannidis, MD, of the Feinstein Institutes for Medical Research at Northwell Health.
The Company also announced that two featured communications have been accepted for oral presentation at CINP 2026, to be held June 26–29, 2026 in Glasgow, United Kingdom. Both present data from the Phase 2b
GH001-TRD-201 trial of GH001 in treatment-resistant depression (TRD).
Details:
Featured Communication (Oral Presentation)
Presentation Title: Rapid Antidepressant Effects of Inhaled GH001 in Treatment-Resistant Depression: Results
from a Phase 2b, Double-Blind, Randomized Controlled Trial With 6-Month Follow-Up
Presenting Author: Wiesław J. Cubała, MD, PhD, Medical University of Gdańsk, Gdańsk, Poland
Date and Time: Saturday, June 27, 2026, 12:30–12:45 BST
Featured Communication (Oral Presentation)
Presentation Title: Safety and Tolerability Results from a Phase 2b, Double-Blind Trial With an Open-Label
Extension of GH001 in Treatment-Resistant Depression
Presenting Author: Bernhard T. Baune, MD, PhD, MPH, MBA, FRANZCP, University of Münster, Münster, Germany
Date and Time: Sunday, June 28, 2026, 12:15–12:30 BST
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.
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.
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 the therapeutic potential of mebufotenin and GH001; strategies and prospects for our business; our plans and expectations for the continued clinical development of GH001 in PPD, TRD and other indications; the timing of scientific
publications and presentations; and 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, the risk that preliminary results from small, open-label,
proof-of-concept trials, including our Phase 2a trial of GH001 in PPD, may not be predictive of, or replicated in, larger, randomized, placebo-controlled trials; the risk that we may not initiate or complete further clinical development of GH001 on
the timelines we are targeting or at all; the risk that future clinical trials of GH001 are placed on clinical hold by the FDA or fail to enroll on the timelines we are targeting; risks relating to adverse public perception of mebufotenin and other
psychedelic or controlled substances and their classification under the Controlled Substances Act; and those other risks 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
FAQ
What did GH Research (GHRS) report in its June 2026 6-K filing?
GH Research reported publication of full Phase 2a results for GH001 in postpartum depression and announced two oral presentations at CINP 2026 highlighting Phase 2b treatment-resistant depression data, including primary endpoint achievement with a MADRS reduction versus placebo.
What were the key findings from GH Research’s Phase 2a postpartum depression trial?
The open-label Phase 2a trial enrolled 10 adult women with postpartum depression. All achieved rapid remission within hours after a single-day inhaled GH001 treatment, with remission sustained through Day 8 and a favorable safety profile, allowing only brief interruption of breastfeeding during treatment.
Which GH001 data will GH Research present at CINP 2026?
GH Research will present two featured oral communications at CINP 2026, both from the Phase 2b GH001-TRD-201 trial in treatment-resistant depression, covering rapid antidepressant effects with six-month follow-up and separate safety and tolerability results, including an open-label extension component.
How did GH001 perform in the Phase 2b treatment-resistant depression trial?
In the Phase 2b GH001-TRD-201 trial, the primary endpoint was met, with a MADRS reduction from baseline of -15.5 points compared with placebo on Day 8 (P<0.0001). This controlled trial result supports ongoing development of GH001 in treatment-resistant depression.
Where were GH Research’s postpartum depression results with GH001 published?
The postpartum depression Phase 2a results were published in The Journal of Clinical Psychiatry. The article, titled “Inhaled Mebufotenin (GH001) for Adult Patients with Postpartum Depression,” reports full data from the single-arm, open-label trial and is identified by DOI 10.4088/JCP.25m16284.
What risks and uncertainties does GH Research highlight around GH001 development?
GH Research cautions that small, open-label proof-of-concept results may not predict outcomes in larger randomized trials. It also cites risks around initiating or completing future GH001 studies, potential clinical holds, enrollment challenges, and adverse public perception of mebufotenin and other psychedelic or controlled substances.