Groowe Groowe BETA / Newsroom
⏱ News is delayed by 15 minutes. Sign in for real-time access. Sign in

Form 8-K

sec.gov

8-K — Gain Therapeutics, Inc.

Accession: 0001104659-26-112624

Filed: 2026-10-01

Period: 2026-10-01

CIK: 0001819411

SIC: 2834 (PHARMACEUTICAL PREPARATIONS)

Item: Other Events

Documents

8-K — tm2626750d1_8k.htm (Primary)

XML — IDEA: XBRL DOCUMENT (R1.htm)

8-K — FORM 8-K

8-K (Primary)

Filename: tm2626750d1_8k.htm · Sequence: 1

false

0001819411

0001819411

2026-10-01

2026-10-01

iso4217:USD

xbrli:shares

iso4217:USD

xbrli:shares

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM

8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the

Securities Exchange Act of 1934

Date of Report (Date of earliest event reported):

October 1, 2026

Gain Therapeutics, Inc.

(Exact name of registrant as specified in its charter)

Delaware

001-40237

85-1726410

(State or Other Jurisdiction

of Incorporation)

(Commission File

Number)

(I.R.S. Employer

Identification No.)

4800 Montgomery Lane, Suite 220

Bethesda, Maryland 20814

(Address of principal executive offices, including zip code)

(301)

500-1556

(Registrant’s telephone number, including area code)

N/A

(Former name or former address, if changed since

last report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under

any of the following provisions:

¨ Written

communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

¨ Soliciting

material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

¨ Pre-commencement

communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

¨ Pre-commencement

communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant

to Section 12(b) of the Act:

Title

of Each Class:

Trading

Symbol

Name

of Each Exchange on which Registered

Common Stock, par value $0.0001 per share

GANX

The

Nasdaq Stock

Market LLC

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (17 CFR§230.405)

or Rule 12b-2 of the Securities Exchange Act of 1934 (17 CFR §240.12b-2).

Emerging growth company x

If an emerging growth company,

indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised

financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ¨

Item 8.01. Other Events.

On October 1, 2026, Gain Therapeutics, Inc. (the

“Company”) issued a press release announcing the presentation of a poster at the International Congress of Parkinson’s

Disease and Movement Disorders, being held October 4-8, 2026, in Seoul, Korea. The poster outlines long-term open-label extension (“OLE”)

data from the Phase 1b clinical study of rexaceract showing stabilization of Movement Disorder Society-Sponsored Revision of the Unified

Parkinson’s Disease Rating Scale (“MDS-UPDRS”) scores over 360 days (12 months) of dosing, supporting the disease-modifying

potential in Parkinson’s disease (“PD”). The data, which includes safety, tolerability, and clinical scores from the

Phase 1b nine-month study extension support continued development of rexaceract for PD.

As of August 31, 2026, 12 of the 13

evaluable patients have completed the full 12-month administration of rexaceract in the open-label extension, with one additional

participant scheduled to complete dosing in November 2026. In the 12 evaluable participants, MDS-UPDRS motor scores were stable over

the 12-month study period with rexaceract, demonstrating no clinically meaningful progression of motor symptoms on the MDS-UPDRS

Parts II and III. A clinically meaningful change in PD disease progression is generally accepted to be an increase in MDS-UPDRS Part

II and III together of approximately 6 points over a year, which also is the mean annual rate of disease progression among

individuals with early PD. Part II of the MDS-UPDRS is patient-reported motor aspects of experiences of daily living and assesses

the impact of PD on activities such as eating, dressing, walking, and other everyday functions. Part III is a clinician-assessed

motor examination, evaluating features such as tremor, rigidity, bradykinesia, speech, gait, and postural stability.

The Company expects to submit a new Phase 2 study

protocol to the U.S. Food and Drug Administration (the “FDA”) in the coming weeks, informed by insights provided by the Phase

1b study results and recent discussion with potential partners, and initiate the Phase 2 clinical trial of rexaceract in people with Parkinson’s

disease in the first quarter of 2027.

Additionally, participants with both high and

low baseline levels of the glucocerebrosidase (“GCase”) substrate glucosylsphingosine (“GluSph”) in cerebrospinal

fluid (“CSF”) show stabilization of MDS-UPDRS motor scores after 12 months and no clinically meaningful progression of motor

symptoms observed on the MDS-UPDRS Parts II and III. Though participants with high baseline levels of CSF GluSph experienced a large decrease

back towards levels observed in healthy individuals after 90 days of treatment along with a quicker observed response to rexaceract, both

groups’ MDS-UPDRS scores remained stable to baseline through 12 months of dosing.

Elevated GluSph is a hallmark of GCase dysfunction

and has been shown to increase the aggregation of alpha synuclein and to impair mitochondrial function and other intracellular processes

in neurons. A reduction in GluSph in CSF after treatment with rexaceract suggests increased GCase activity in the brain, which is expected

to impact the progression of Parkinson’s disease.

Preliminary long-term data suggest that rexaceract

is safe and generally well tolerated over 12 months of dosing. No new safety signals were observed and overall, a lower incidence of treatment-emergent

adverse events occurred in Part 2 of the study (nine-month open-label extension) compared with Part 1 (initial three-month administration).

Results from a Phase 1 study of rexaceract in

healthy volunteers demonstrated favorable safety and tolerability, plasma and central nervous system (“CNS”) exposures in

the projected therapeutic range, and target engagement with an increase in GCase activity among those receiving rexaceract at clinically

relevant doses.

Rexaceract is currently being evaluated in a Phase 1b clinical trial

for the treatment of PD with or without a GBA1 mutation. The primary endpoint of the trial, which enrolled participants across seven sites

in Australia, is to evaluate the safety and tolerability of rexaceract after three months of dosing in people with PD. The Phase 1b study

extension allowed participants to continue to be treated with rexaceract for up to a total of 12 months.

Cautionary Note Regarding Forward-Looking Statements

This Current Report on Form 8-K 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 rexaceract; expectations regarding the timing of

patient enrollment and the completion and timing of results from the Phase 1b clinical study for rexaceract, including any extension studies;

the timing of any submissions to the FDA or other regulatory bodies and agencies; the timing of the commencement of the Phase 2 clinical

study for rexaceract; the design of the Phase 2 clinical study and whether the FDA will accept a new Phase 2 protocol; the Company’s

ability to enroll patients in its planned Phase 2 clinical study for rexaceract; whether results from preclinical studies and initial

or interim data from early clinical trials, including open-label data, will be predictive of the final results of the clinical trials

or future trials; the Company’s ability to replicate positive results from earlier preclinical studies or clinical trials in current

or future clinical trials; the Company’s business development activities, strategic collaborations, licensing opportunities and

financing activities; the advancement, prioritization and timing of the Company’s pipeline programs, including GT-04686; 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 Annual Report on Form 10-K for the year ended December 31, 2025 and other filings

made with the Securities and Exchange Commission. 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 Current

Report on Form 8-K. The Company has no obligation, and expressly disclaims any obligation, to update, revise or correct any of the forward-looking

statements, whether because of new information, future events or otherwise.

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 hereunto

duly authorized.

GAIN THERAPEUTICS, INC.

Dated: October 1, 2026

By:

/s/ Gene Mack

Gene Mack

Chief Executive Officer

XML — IDEA: XBRL DOCUMENT

XML

Filename: R1.htm · Sequence: 6

v3.26.3

Cover

Oct. 01, 2026

Cover [Abstract]

Document Type

8-K

Amendment Flag

false

Document Period End Date

Oct. 01, 2026

Entity File Number

001-40237

Entity Registrant Name

Gain Therapeutics, Inc.

Entity Central Index Key

0001819411

Entity Tax Identification Number

85-1726410

Entity Incorporation, State or Country Code

DE

Entity Address, Address Line One

4800 Montgomery Lane

Entity Address, Address Line Two

Suite 220

Entity Address, City or Town

Bethesda

Entity Address, State or Province

MD

Entity Address, Postal Zip Code

20814

City Area Code

301

Local Phone Number

500-1556

Written Communications

false

Soliciting Material

false

Pre-commencement Tender Offer

false

Pre-commencement Issuer Tender Offer

false

Title of 12(b) Security

Common Stock, par value $0.0001 per share

Trading Symbol

GANX

Security Exchange Name

NASDAQ

Entity Emerging Growth Company

true

Elected Not To Use the Extended Transition Period

false

X

- Definition

Boolean flag that is true when the XBRL content amends previously-filed or accepted submission.

+ References

No definition available.

+ Details

Name:

dei_AmendmentFlag

Namespace Prefix:

dei_

Data Type:

xbrli:booleanItemType

Balance Type:

na

Period Type:

duration

X

- Definition

Area code of city

+ References

No definition available.

+ Details

Name:

dei_CityAreaCode

Namespace Prefix:

dei_

Data Type:

xbrli:normalizedStringItemType

Balance Type:

na

Period Type:

duration

X

- Definition

Cover page.

+ References

No definition available.

+ Details

Name:

dei_CoverAbstract

Namespace Prefix:

dei_

Data Type:

xbrli:stringItemType

Balance Type:

na

Period Type:

duration

X

- Definition

For the EDGAR submission types of Form 8-K: the date of the report, the date of the earliest event reported; for the EDGAR submission types of Form N-1A: the filing date; for all other submission types: the end of the reporting or transition period. The format of the date is YYYY-MM-DD.

+ References

No definition available.

+ Details

Name:

dei_DocumentPeriodEndDate

Namespace Prefix:

dei_

Data Type:

xbrli:dateItemType

Balance Type:

na

Period Type:

duration

X

- Definition

The type of document being provided (such as 10-K, 10-Q, 485BPOS, etc). The document type is limited to the same value as the supporting SEC submission type, or the word 'Other'.

+ References

No definition available.

+ Details

Name:

dei_DocumentType

Namespace Prefix:

dei_

Data Type:

dei:submissionTypeItemType

Balance Type:

na

Period Type:

duration

X

- Definition

Address Line 1 such as Attn, Building Name, Street Name

+ References

No definition available.

+ Details

Name:

dei_EntityAddressAddressLine1

Namespace Prefix:

dei_

Data Type:

xbrli:normalizedStringItemType

Balance Type:

na

Period Type:

duration

X

- Definition

Address Line 2 such as Street or Suite number

+ References

No definition available.

+ Details

Name:

dei_EntityAddressAddressLine2

Namespace Prefix:

dei_

Data Type:

xbrli:normalizedStringItemType

Balance Type:

na

Period Type:

duration

X

- Definition

Name of the City or Town

+ References

No definition available.

+ Details

Name:

dei_EntityAddressCityOrTown

Namespace Prefix:

dei_

Data Type:

xbrli:normalizedStringItemType

Balance Type:

na

Period Type:

duration

X

- Definition

Code for the postal or zip code

+ References

No definition available.

+ Details

Name:

dei_EntityAddressPostalZipCode

Namespace Prefix:

dei_

Data Type:

xbrli:normalizedStringItemType

Balance Type:

na

Period Type:

duration

X

- Definition

Name of the state or province.

+ References

No definition available.

+ Details

Name:

dei_EntityAddressStateOrProvince

Namespace Prefix:

dei_

Data Type:

dei:stateOrProvinceItemType

Balance Type:

na

Period Type:

duration

X

- Definition

A unique 10-digit SEC-issued value to identify entities that have filed disclosures with the SEC. It is commonly abbreviated as CIK.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Exchange Act

-Number 240

-Section 12

-Subsection b-2

+ Details

Name:

dei_EntityCentralIndexKey

Namespace Prefix:

dei_

Data Type:

dei:centralIndexKeyItemType

Balance Type:

na

Period Type:

duration

X

- Definition

Indicate if registrant meets the emerging growth company criteria.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Exchange Act

-Number 240

-Section 12

-Subsection b-2

+ Details

Name:

dei_EntityEmergingGrowthCompany

Namespace Prefix:

dei_

Data Type:

xbrli:booleanItemType

Balance Type:

na

Period Type:

duration

X

- Definition

Indicate if an emerging growth company has elected not to use the extended transition period for complying with any new or revised financial accounting standards.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Securities Act

-Number 7A

-Section B

-Subsection 2

+ Details

Name:

dei_EntityExTransitionPeriod

Namespace Prefix:

dei_

Data Type:

xbrli:booleanItemType

Balance Type:

na

Period Type:

duration

X

- Definition

Commission file number. The field allows up to 17 characters. The prefix may contain 1-3 digits, the sequence number may contain 1-8 digits, the optional suffix may contain 1-4 characters, and the fields are separated with a hyphen.

+ References

No definition available.

+ Details

Name:

dei_EntityFileNumber

Namespace Prefix:

dei_

Data Type:

dei:fileNumberItemType

Balance Type:

na

Period Type:

duration

X

- Definition

Two-character EDGAR code representing the state or country of incorporation.

+ References

No definition available.

+ Details

Name:

dei_EntityIncorporationStateCountryCode

Namespace Prefix:

dei_

Data Type:

dei:edgarStateCountryItemType

Balance Type:

na

Period Type:

duration

X

- Definition

The exact name of the entity filing the report as specified in its charter, which is required by forms filed with the SEC.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Exchange Act

-Number 240

-Section 12

-Subsection b-2

+ Details

Name:

dei_EntityRegistrantName

Namespace Prefix:

dei_

Data Type:

xbrli:normalizedStringItemType

Balance Type:

na

Period Type:

duration

X

- Definition

The Tax Identification Number (TIN), also known as an Employer Identification Number (EIN), is a unique 9-digit value assigned by the IRS.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Exchange Act

-Number 240

-Section 12

-Subsection b-2

+ Details

Name:

dei_EntityTaxIdentificationNumber

Namespace Prefix:

dei_

Data Type:

dei:employerIdItemType

Balance Type:

na

Period Type:

duration

X

- Definition

Local phone number for entity.

+ References

No definition available.

+ Details

Name:

dei_LocalPhoneNumber

Namespace Prefix:

dei_

Data Type:

xbrli:normalizedStringItemType

Balance Type:

na

Period Type:

duration

X

- Definition

Boolean flag that is true when the Form 8-K filing is intended to satisfy the filing obligation of the registrant as pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Exchange Act

-Number 240

-Section 13e

-Subsection 4c

+ Details

Name:

dei_PreCommencementIssuerTenderOffer

Namespace Prefix:

dei_

Data Type:

xbrli:booleanItemType

Balance Type:

na

Period Type:

duration

X

- Definition

Boolean flag that is true when the Form 8-K filing is intended to satisfy the filing obligation of the registrant as pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Exchange Act

-Number 240

-Section 14d

-Subsection 2b

+ Details

Name:

dei_PreCommencementTenderOffer

Namespace Prefix:

dei_

Data Type:

xbrli:booleanItemType

Balance Type:

na

Period Type:

duration

X

- Definition

Title of a 12(b) registered security.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Exchange Act

-Number 240

-Section 12

-Subsection b

+ Details

Name:

dei_Security12bTitle

Namespace Prefix:

dei_

Data Type:

dei:securityTitleItemType

Balance Type:

na

Period Type:

duration

X

- Definition

Name of the Exchange on which a security is registered.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Exchange Act

-Number 240

-Section 12

-Subsection d1-1

+ Details

Name:

dei_SecurityExchangeName

Namespace Prefix:

dei_

Data Type:

dei:edgarExchangeCodeItemType

Balance Type:

na

Period Type:

duration

X

- Definition

Boolean flag that is true when the Form 8-K filing is intended to satisfy the filing obligation of the registrant as soliciting material pursuant to Rule 14a-12 under the Exchange Act.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Exchange Act

-Number 240

-Section 14a

-Subsection 12

+ Details

Name:

dei_SolicitingMaterial

Namespace Prefix:

dei_

Data Type:

xbrli:booleanItemType

Balance Type:

na

Period Type:

duration

X

- Definition

Trading symbol of an instrument as listed on an exchange.

+ References

No definition available.

+ Details

Name:

dei_TradingSymbol

Namespace Prefix:

dei_

Data Type:

dei:tradingSymbolItemType

Balance Type:

na

Period Type:

duration

X

- Definition

Boolean flag that is true when the Form 8-K filing is intended to satisfy the filing obligation of the registrant as written communications pursuant to Rule 425 under the Securities Act.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Securities Act

-Number 230

-Section 425

+ Details

Name:

dei_WrittenCommunications

Namespace Prefix:

dei_

Data Type:

xbrli:booleanItemType

Balance Type:

na

Period Type:

duration