Gain Therapeutics Receives Australian Approval of Phase 1b Dosing Extension and Reports Positive Independent Data Monitoring Committee Recommendation

Ongoing Phase 1b trial of GT-02287 to be extended by an additional nine months for participants who enrolled in the original three-month study design

The independent data monitoring committee (DMC) met recently and recommended to continue the study with no changes to study design

Gain Therapeutics, Inc. (Nasdaq: GANX) ("Gain", or the "Company"), a clinical-stage biotechnology company leading the discovery and development of the next generation of allosteric small molecule therapies, today announced the Company has received approval from the Bellberry Human Research Ethics Committee and Alfred Hospital Ethics Committee to extend dosing by an additional nine months in its ongoing Phase 1b clinical study of GT-022887, beyond the 90-day period currently allowed in protocol.

The dosing extension will be offered to participants who have completed 90 days of treatment and will provide them the opportunity to continue treatment with GT-02287 for a total of 12 months. The majority of participants who have already completed the 90-day dosing period have confirmed their interest in joining the extension.

Separately, the independent data monitoring committee (DMC) has identified no safety concerns and recommended to continue the study with no changes after its review of interim safety data from the ongoing Phase 1b study of GT-02287.

"The approval by Australian authorities of the dosing extension and the DMC's positive recommendation represent important milestones in GT-02287's clinical development program," said Gene Mack, President and CEO of Gain Therapeutics. "We look forward to transitioning eligible participants into the extension phase to further assess long-term safety, tolerability, functional changes scored according to the Movement Disorder Society Unified Parkinson's Disease Rating Scale, and biomarker activity from cerebrospinal fluid. The additional data is intended to support Phase 2 planning and the decision to extend dosing reflects encouraging early feedback from patients and clinicians, while underscoring our commitment to developing a disease-modifying therapy for Parkinson's disease," concluded Mr. Mack.

About GT-02287
Gain Therapeutics' lead drug candidate, GT-02287, is in clinical development for the treatment of Parkinson's disease (PD) with or without a GBA1 mutation. The orally administered, brain-penetrant small molecule is an allosteric enzyme modulator that restores the function of the lysosomal enzyme glucocerebrosidase (GCase) which becomes misfolded and impaired due to mutations in the GBA1 gene, the most common genetic abnormality associated with PD, or other age-related stress factors. In preclinical models of PD, GT-02287 restored GCase enzymatic function, reduced ER stress, lysosomal and mitochondrial pathology, aggregated α-synuclein, neuroinflammation and neuronal death, as well as plasma neurofilament light chain (NfL) levels, a biomarker of neurodegeneration. In rodent models of both GBA1-PD and idiopathic PD, GT-02287 was shown to rescue deficits in motor function and gait and prevent the development of deficits in complex behaviors such as nesting.

Compelling preclinical data in models of both GBA1-PD and idiopathic PD, demonstrating a disease-modifying effect after administration of GT-02287, suggest that GT-02287 may have the potential to slow or stop the progression of Parkinson's disease.

Results from a Phase 1 study of GT-02287 in healthy volunteers demonstrated favorable safety and tolerability, plasma and CNS exposures in the projected therapeutic range, and target engagement with a >50% increase in glucocerebrosidase (GCase) activity among those receiving GT-02287 at clinically relevant doses.

GT-02287 is currently being evaluated in a Phase 1b clinical trial for the treatment of Parkinson's disease with or without a GBA1 mutation. The primary endpoint of the trial, which is currently enrolling participants across 7 sites in Australia, is to evaluate the safety and tolerability of GT-02287 after 3 months of dosing in people with Parkinson's disease.

Gain's lead program in Parkinson's disease has been awarded funding support early in its development from The Michael J. Fox Foundation for Parkinson's Research (MJFF) and The Silverstein Foundation for Parkinson's with GBA, as well as from the Eurostars-2 joint program with co-funding from the European Union Horizon 2020 research and Innosuisse – Swiss Innovation Agency.

About Gain Therapeutics, Inc.
Gain Therapeutics, Inc. is a clinical-stage biotechnology company leading the discovery and development of next generation allosteric therapies. Gain's lead drug candidate, GT-02287 is currently being evaluated for the treatment of Parkinson's disease with or without a GBA1 mutation in a Phase 1b clinical trial. GT-02287 has further potential in Gaucher's disease, dementia with Lewy bodies, and Alzheimer's disease. Gain has multiple undisclosed preclinical assets targeting lysosomal storage disorders, metabolic diseases, and solid tumors.

Gain's unique approach enables the discovery of novel, allosteric small molecule modulators that can restore or disrupt protein function. Deploying its highly advanced Magellan™ platform, Gain is accelerating drug discovery and unlocking novel disease-modifying treatments for untreatable or difficult-to-treat disorders including neurodegenerative diseases, rare genetic disorders and oncology.

Forward-Looking Statements
This release contains "forward-looking statements" made pursuant to the safe harbor provisions of the Private Securities Litigation Reform Act of 1995. These statements are typically preceded by words such as "believes," "expects," "anticipates," "intends," "will," "may," "should," or similar expressions. These forward-looking statements reflect management's current knowledge, assumptions, judgment and expectations regarding future performance or events. Although management believes that the expectations reflected in such statements are reasonable, they give no assurance that such expectations will prove to be correct or that those goals will be achieved, and you should be aware that actual results could differ materially from those contained in the forward-looking statements. Forward-looking statements are subject to a number of risks and uncertainties, including, but not limited to, statements regarding: the development of the Company's current or future product candidates including GT-02287; expectations regarding the completion, quality and timing of results from a Phase 1b clinical study for GT-02287; expectations regarding the timing of patient enrollment for a Phase 1b clinical study for GT-02287, including the dose extension study; the timing of any submissions to the FDA or other regulatory bodies and agencies; and the potential therapeutic and clinical benefits of the Company's product candidates. For a further description of the risks and uncertainties that could cause actual results to differ from those expressed in these forward-looking statements, as well as risks relating to the Company's business in general, please refer to the Company's Form 10-K for the year ended December 31, 2024. All forward-looking statements are expressly qualified in their entirety by this cautionary notice. You are cautioned not to place undue reliance on any forward-looking statements, which speak only as of the date of this release. We have no obligation, and expressly disclaim any obligation, to update, revise or correct any of the forward-looking statements, whether because of new information, future events or otherwise.

Investors:
Gain Therapeutics, Inc.
Apaar Jammu
Manager, Investor Relations and Public Relations
ajammu@gaintherapeutics.com

LifeSci Advisors LLC
Chuck Padala
Managing Director
chuck@lifesciadvisors.com

Media:
Russo Partners LLC
Nic Johnson and Elio Ambrosio
nic.johnson@russopartnersllc.com
elio.ambrosio@russopartnersllc.com
(760) 846-9256