Exhibit 99.1

ADDEX THERAPEUTICS LTD

INDEX TO UNAUDITED INTERIM CONDENSED CONSOLIDATED FINANCIAL STATEMENTS

Addex Therapeutics │ Unaudited Interim Condensed Consolidated Financial Statements

Unaudited Interim Condensed Consolidated Balance Sheets

as of September 30, 2025, and December 31, 2024

The accompanying notes form an integral part of these consolidated financial statements.

Addex Therapeutics │ Unaudited Interim Condensed Consolidated Financial Statements

Unaudited Interim Condensed Consolidated Statements of Profit or Loss

for the three-month and nine-month periods ended September 30, 2025 and 2024

The accompanying notes form an integral part of these consolidated financial statements.

Addex Therapeutics │ Unaudited Interim Condensed Consolidated Financial Statements

Unaudited Interim Condensed Consolidated Statements of Comprehensive Income or Loss

for the three-month and nine-month periods ended September 30, 2025 and 2024

The accompanying notes form an integral part of these consolidated financial statements.

Addex Therapeutics │ Unaudited Interim Condensed Consolidated Financial Statements

Unaudited Interim Condensed Consolidated Statements of Changes in Equity

for the nine-month periods ended September 30, 2025 and 2024

The accompanying notes form an integral part of these consolidated financial statements.

Addex Therapeutics │ Unaudited Interim Condensed Consolidated Financial Statements

Unaudited Interim Condensed Consolidated Statements of Changes in Equity

for the three-month periods ended September 30, 2024

The accompanying notes form an integral part of these consolidated financial statements.

Addex Therapeutics │ Unaudited Interim Condensed Consolidated Financial Statements

Unaudited Interim Condensed Consolidated Statements of Changes in Equity

for the three-month periods ended September 30, 2025

The accompanying notes form an integral part of these consolidated financial statements.

Addex Therapeutics │ Unaudited Interim Condensed Consolidated Financial Statements

Unaudited Interim Condensed Consolidated Statements of Cash Flows

for the nine-month periods ended September 30, 2025 and 2024

The accompanying notes form an integral part of these consolidated financial statements.

Addex Therapeutics │ Unaudited Interim Condensed Consolidated Financial Statements │Notes

Unaudited Notes to the Interim Condensed Consolidated Financial Statements

for the nine-month period ended September 30, 2025

(Amounts in Swiss francs)

1. General information

Addex Therapeutics Ltd (the “Company”) and its subsidiaries (together, the “Group”) are a clinical stage biopharmaceutical company focused on developing a portfolio of novel small molecule allosteric modulators for neurological disorders.

The Company is a Swiss stockholding corporation domiciled c/o Addex Pharma SA, Chemin des Aulx 12, CH 1228 Plan-les-Ouates, Geneva, Switzerland and the parent company of Addex Pharma SA, Addex Pharmaceuticals France SAS and Addex Pharmaceuticals Inc. Addex Therapeutics also owns a 20% equity interest in Neurosterix US Holdings LLC, USA. Neurosterix US Holdings LLC fully owns directly Neurosterix Swiss Holdings AG, Switzerland and indirectly Neurosterix Pharma Sàrl whose principal place of business is Chemin des Mines 9, CH 1202 Geneva, Switzerland.

The Groups principal place of business is Chemin des Mines 9, CH 1202 Geneva, Switzerland. Its registered shares are traded at the SIX Swiss Exchange, under the ticker symbol ADXN and its American Depositary Shares (ADSs) on the Nasdaq Stock Market under the symbol ADXN. ADSs represents shares that continue to be admitted to trading on SIX Swiss Exchange.

These interim condensed consolidated financial statements have been approved for issuance by the Board of Directors on December 3, 2025.

2. Basis of preparation

These interim condensed consolidated financial statements for the nine-month period ended September 30, 2025, have been prepared under the historic cost convention and in accordance with IAS 34 “Interim Financial Reporting” and are presented in a format consistent with the consolidated financial statements under IAS 1 “Presentation of Financial Statements”. However, they do not include all of the notes that would be required in a complete set of financial statements. Thus, this interim financial report should be read in conjunction with the consolidated financial statements for the year ended December 31, 2024.

Interim financial results are not necessarily indicative of results anticipated for the full year. The preparation of these unaudited interim condensed consolidated financial statements made in accordance with IAS 34 requires the use of estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Although these estimates are based on management’s best knowledge of current events and actions, actual results ultimately may differ from those estimates. The areas involving a higher degree of judgment which are significant to the interim condensed consolidated financial statements are disclosed in note 4 to the consolidated financial statements for the year ended December 31, 2024.

A number of new or amended standards and interpretations became applicable for financial reporting periods beginning on or after January 1, 2025. Of the latter, the Group noted the amendment of IAS 21: The Effects of Changes in Foreign Exchange rates relating to the exchange rate of currencies that are not exchangeable. The Group concluded that this amendment was not relevant as the Group only uses major currencies. The Group is also assessing other new and revised standards which are not mandatory until after 2025 and noted that IFRS 18 – Presentation and Disclosure in Financial Statements will replace IAS 1 - Presentation of Financial Statements - from January 1, 2027 and may impact the presentation and structure of the Group’s primary financial statements and related disclosures.

Due to rounding, numbers presented throughout these interim condensed consolidated financial statements may not add up precisely to the totals provided. All ratios and variances are calculated using the underlying amounts rather than the presented rounded amounts. Where necessary, comparative figures have been revised to conform with the current year 2025.

Addex Therapeutics │ Unaudited Interim Condensed Consolidated Financial Statements │Notes

3. Material accounting estimates and judgments

The Group makes estimates and assumptions concerning the future. These estimates and judgments are continually evaluated and are based on historical experience and other factors, including expectations of future events that are believed to be reasonable under the circumstances. The resulting accounting estimates will, by definition, seldom equal the related actual results. The estimates and assumptions that have a significant risk of causing a material adjustment to the carrying amounts of assets and liabilities or may have had a significant impact on the reported results are disclosed below:

Going concern

The Group’s accounts are prepared on a going concern basis. To date, the Group has financed its cash requirements primarily from share issuances, licensing certain of its research and development stage products and selling its allosteric modulator drug discovery technology platform with a portfolio of preclinical programs. The Group is a development-stage enterprise and is exposed to all the risks inherent in establishing a business. The Group expects that its existing cash and cash equivalents, at the issuance date of these unaudited interim condensed consolidated financial statements will be sufficient to fund its operations and meet all of its obligations as they fall due, through mid-June 2026. These factors individually and collectively indicate that a material uncertainty exists that raises substantial doubt about the Group’s ability to continue as a going concern for one year from the date of issuance of these unaudited interim condensed consolidated financial statements. The future viability of the Group is dependent on its ability to raise additional capital through public or private financings or collaboration agreements to finance its future operations, which may be delayed due to reasons outside of the Group’s control including health pandemics and geopolitical risks. The sale of additional equity may dilute existing shareholders. The inability to obtain funding, as and when needed, would have a negative impact on the Group’s financial condition and ability to pursue its business strategies. If the Group is unable to obtain the required funding to run its operations and to develop and commercialize its product candidates, the Group could be forced to delay, reduce or stop some or all of its research and development programs to ensure it remains solvent. Management continues to explore options to obtain additional funding, including through collaborations with third parties related to the future potential development and/or commercialization of its product candidates. However, there is no assurance that the Group will be successful in raising funds, closing collaboration agreements, obtaining sufficient funding on terms acceptable to the Group, or if at all, which could have a material adverse effect on the Group’s business, results of operations and financial condition.

The Business of the Group could be adversely affected by health pandemics and geopolitical risks

The business of the Group could be adversely affected by health epidemics and geopolitical risks in regions where the Group or partners have concentrations of clinical trial sites or other business operations and could cause significant disruption in the operations of third-party manufacturers and CROs upon whom the Group or partners rely. Health pandemics may pose the risk that the Group, employees, contractors, collaborators, and partners may be prevented from conducting certain pre-clinical tests, clinical trials or other business activities for an indefinite period of time, including due to travel restrictions, quarantines, “stay-at-home” and “shelter-in-place” orders or shutdowns that have been or may in the future be requested or mandated by governmental authorities. For example, the COVID-19 pandemic has impacted the business of the Group and clinical trials led by the Group or partners, including as a result of delays or difficulties in clinical site initiation, difficulties in recruiting and retaining clinical site investigators and clinical site staff and interruption of the clinical supply chain or key clinical trial activities, such as clinical trial site monitoring, and supply chain interruptions caused by restrictions for the supply of materials for drug candidates or other materials necessary to manufacture product to conduct clinical and preclinical tests. Geopolitical risks such as Russia-Ukraine war or Middle East conflict may create global security concerns including the possibility of an expanded regional or global conflict and potential ramifications such as disruption of the supply chain including research and development activities being conducted by the Group and its strategic partners. Delays in research and development activities of the Group and its partners could increase associated costs and, depending upon the duration of any delays, require the Group and its partners to find alternative suppliers at additional expense. In addition, Russia-Ukraine war has had significant ramifications on global financial markets, which may adversely impact the ability of the Group to raise capital on favorable terms or at all.

Discontinued operations, assets and liabilities held for sale related to the Neurosterix Transaction

On April 2, 2024, the Group sold a part of its business constituting its allosteric modulator drug discovery technology platform and a portfolio of preclinical programs (note 21). As a consequence, the Group recognized discontinued operations in the statements of profit or loss under “net profit or loss from discontinued operations” for the nine month-period ended September 30, 2024, in accordance with IFRS 5. The Group identified as well, cash flows from discontinued operations for the nine-month period ended September 30, 2024 (note 21). The identification of discontinued operations may require some degree of judgement.

Fair value measurement of financial instruments

The Group measures its financial instruments at fair value at each reporting date. Fair value is the price that would be received to sell its financial asset in an orderly transaction between market participants at the measurement date, in the principal or most advantageous market, under current market conditions.

Fair value measurements are categorized into three levels based on the degree to which inputs to the valuation techniques are observable:

       ●     Level 1: Quoted prices (unadjusted) in active markets for identical assets;

       ●     Level 2: Inputs other than quoted prices included within Level 1 that are all observable, either directly or indirectly used to measure the fair value;

       ●     Level 3: One or more of the significant inputs used to measure fair value is not based on observable market data. This is the case for unlisted equity securities or financial instruments where climate risk gives rise to a significant unobservable adjustment.

Addex Therapeutics │ Unaudited Interim Condensed Consolidated Financial Statements │Notes

The Group uses appropriate valuation techniques in the circumstances and maximizes the use of relevant observable inputs. The transfers between levels are assessed at the end of each reporting period.

Investments accounted for using the equity method

The Group received an equity interest of 20% in Neurosterix US Holdings LLC as part of the Neurosterix Transaction. The initial recognition of the investment has been accounted at a fair value based on a financial valuation of Neurosterix Group. This carrying amount has been decreased to recognize the share of loss of Neurosterix Group and tested for impairment whenever events, factors or changes in circumstances indicate that it may not be recoverable.

Financial assets at fair value through Other Comprehensive Income (OCI)

The financial assets at fair value through OCI relate to strategic investments made by the Group into early stage R&D companies. The Group made the irrevocable election to classify these strategic investments, that are not held for trading, at fair value through OCI. The valuation at fair value is based on prices paid by investors during recent fundings (note 23). At each closing, the investments are tested by the Group in order to reflect any change in value due to events, factors or changes in circumstances.

Derivative financial instruments

Derivative financial instruments relate to Phantom shares and Warrants received as part of the purchase of strategic investment. Derivative financial instruments are accounted at fair value through the statements of profit or loss in accordance with IFRS 9, because they are considered as held for trading. The fair value is measured using the Black-Scholes and binomial valuation models (note 24). A number of assumptions related to the volatility of the underlying shares and to the risk-free rate are made in this model. Should the assumptions and estimates underlying the fair value of these instruments vary significantly from management’s estimates, then the fair value of the derivative financial instruments would be materially different from the amounts recognized. At each closing, the investments are tested by the Group in order to reflect any change in value due to events, factors or changes in circumstances.

Revenue recognition

Revenue is primarily from fees related to licenses, milestones and research services. Given the complexity of the relevant agreements, judgements are required to identify distinct performance obligations, allocate the transaction price to these performance obligations and determine when the performance obligations are met. In particular, the Group’s judgement over the estimated stand-alone selling price which is used to allocate the transaction price to the performance obligations is disclosed in note 16.

Grants

Grants are recorded at their fair value when there is reasonable assurance that they will be received and recognized as income when the Group has satisfied the underlying grant conditions. In certain circumstances, grant income may be recognized before explicit grantor acknowledgement that the conditions have been met.

Accrued research and development costs

The Group records accrued expenses for estimated costs of research and development activities conducted by third party service providers. The Group records accrued expenses for estimated costs of research and development activities based upon the estimated amount of services provided, but not yet invoiced, and these costs are included in accrued expenses on the balance sheets and within research and development expenses in the statements of profit or loss. These costs are a significant component of research and development expenses. Accrued expenses for these costs are recorded based on the estimated amount of work completed in accordance with agreements established with these third parties. Due to the nature of estimates, the Group may be required to make changes to the estimates after a reporting period as it becomes aware of additional information about the status or conduct of its research activities.

Share-based compensation

The Group recognizes an expense for share-based compensation based on the valuation of equity incentive units using the Black-Scholes valuation model. A number of assumptions related to the volatility of the underlying shares and to the risk-free rate are made in this model. Should the assumptions and estimates underlying the fair value of these instruments vary significantly from management’s estimates, then the share-based compensation expense would be materially different from the amounts recognized.

Equity instruments

The group records in equity the pre-funded warrants sold to investors and the warrants granted to investors at a fair value calculated using Black-Scholes model. A number of assumptions related to the volatility of the underlying shares and to the risk-free rate are made in this model. Should the assumptions and estimates underlying the fair value of these instruments vary significantly from management’s estimates, then the fair value of the equity instruments would be materially different from the amounts recorded in equity at the grant date.

Addex Therapeutics │ Unaudited Interim Condensed Consolidated Financial Statements │Notes

Pension obligations

The present value of the pension obligations is calculated by an independent actuary and depends on a number of assumptions that are determined on an actuarial basis such as discount rates, future salary and pension increases, and mortality rates. Any changes in these assumptions will impact the carrying amount of pension obligations. The Group determines the appropriate discount rate at the end of each period. This is the interest rate that should be used to determine the present value of estimated future cash outflows expected to be required to settle the pension obligations. In determining the appropriate discount rate, the Group considers the interest rates of high-quality corporate bonds that are denominated in the currency in which the benefits will be paid, and that have terms to maturity approximating the terms of the related pension liability. Other key assumptions for pension obligations are based in part on current market conditions. Additional information is disclosed in note 15.

4. Interim measurement note

Seasonality of the business: The business is not subject to any seasonality, but expenses and corresponding revenue are largely determined by the phase of the respective projects, particularly with regard to external research and development expenditures.

Costs: Costs that incur unevenly during the financial year are anticipated or deferred in the interim report only if it would also be appropriate to anticipate or defer such costs at the end of the financial year.

5. Segment reporting

Management has identified one single operating segment, related to the discovery, development and commercialization of small-molecule pharmaceutical products.

Information about products, services and major customers

External income of the Group is derived from the business of discovery, development and commercialization of pharmaceutical products. Income primarily relates to research services provided to a pharmaceutical company and the fair value of services received from Neurosterix Group at zero cost (notes 10 and 21).

Information about geographical areas

External income is exclusively recorded in the Swiss operating company.

Analysis of revenue from contract with customer and other income by nature is detailed as follows:

Analysis of revenue from contract with customer and other income by major counterparties is detailed as follows:

For more detail, refer to note 16 “Revenue from contract with customer” and note 17 “Other income”.

Addex Therapeutics │ Unaudited Interim Condensed Consolidated Financial Statements │Notes

The geographical allocation of long-lived assets is detailed as follows:

The geographical analysis of operating costs is as follows:

The capital expenditure is nil for the nine-month period ended September 30, 2025 (CHF 1,273 for the nine-month period ended September 30, 2024).

6. Cash and cash equivalents

Split by currency:

The Group invests its cash balances into a variety of current accounts mainly with two Swiss banks whose external credit rating is P-1/A-1.

All cash and cash equivalents were held either at banks or on hand as of September 30, 2025 and December 31, 2024.

7. Other current assets

Total other current assets remained stable at CHF 0.2 million as of September 30, 2025 compared to December 31, 2024. The Group applies the IFRS 9 simplified approach to measuring expected credit losses (“ECL”), which uses a lifetime expected loss allowance for all trade receivables and other receivables. The Group has considered that the trade receivables and other receivables have a low risk of default based on historic loss rates and forward-looking information on macroeconomic factors affecting the ability of the third parties to settle invoices. As a result, expected loss allowance has been deemed as nil as of September 30, 2025 and December 31, 2024.

Addex Therapeutics │ Unaudited Interim Condensed Consolidated Financial Statements │Notes

8. Right-of-use assets

9. Equipment

Addex Therapeutics │ Unaudited Interim Condensed Consolidated Financial Statements │Notes

10. Intangible assets

The service agreement relates to staff and infrastructure provided by Neurosterix Pharma Sàrl at zero cost in accordance with the Neurosterix Transaction (note 21). The depreciation charge was recognized at the rate at which these services were provided. As of January 1, 2025, the agreement was not formally renewed. However, Neurosterix agreed to provide the Group with access to certain employees and infrastructure at zero cost. The fair value of the services received at zero cost has been recognized as other income and other operating expenses for the three-month and nine-month periods ended September 30, 2025, amounted to CHF 19,876 and CHF 125,436, respectively.

11. Non-current financial assets

Security rental deposits relate to office space. The applicable interest rate to such deposits is immaterial, and therefore, the value approximates amortized cost.

12. Payables, accruals and other current liabilities

All payables mature within 3 months. Accrued expenses and trade payables primarily relate to R&D services from contract research organizations, consultants and professional fees. The total amount of payables, accruals and other current liabilities increased by CHF 0.4 million as of September 30, 2025 compared to December 31, 2024. The carrying amounts of payables do not materially differ from their fair values, due to their short-term nature.

13. Share capital

(1) In accordance with Swiss law, the issuance of 6,120,000 new shares through the exercise of pre-funded warrants from December 12, 2023 to December 31, 2023, have been registered in the commercial register on February 20, 2024. As of January 1, 2024, the amount of the share capital as registered in the commercial register is CHF 1,782,344.96 divided into 178,234,496 shares.

Addex Therapeutics │ Unaudited Interim Condensed Consolidated Financial Statements │Notes

As of September 30, 2025, 146,476,085 shares were outstanding excluding 37,878,411 treasury shares directly held by Addex Pharma SA and including 29,904,690 outstanding shares benefiting from our DSPPP, considered as treasury shares under IFRS 2 (note 14).

As of September 30, 2024, 128,273,968 shares were outstanding excluding 56,080,528 treasury shares directly held by Addex Pharma SA and including 29,950,268 outstanding shares benefiting from our DSPPP, considered as treasury shares under IFRS 2 (note 14).

The Group maintains a liquidity agreement with Kepler Cheuvreux (“Kepler”). Under the agreement, the Group has provided Kepler with cash and shares to enable them to buy and sell the Company’s shares. As of September 30, 2025, 114,051 (December 31, 2024: 116,622) treasury shares are recorded under this agreement in the treasury share reserve and CHF 6,860 (December 31, 2024: CHF 6,496) is recorded in other financial assets.

During the nine-month period ended September 30, 2025, the Group sold 18,226,123 treasury shares at an average price of CHF 0.063 per share for total gross proceeds of CHF 1,143,738 (during the nine-month period ended September 30, 2024, the Group sold 3,050,665 treasury shares at an average price of CHF 0.077 per share for gross proceeds of CHF 235,257). Of these treasury shares 10,966,666 were sold at a price of CHF 0.06 per share with 2,741,666 warrants granted by the Group at an exercise price of CHF 0.06 and a 5-year exercise period. The fair value of the warrants amounted to CHF 65,609 and has been recorded in equity as transaction costs. The remaining 7,259,457 treasury shares have been sold under the sale agency agreement with Kepler Cheuvreux at an average price of CHF 0.067 per share for gross proceeds of CHF 485,740.

On February 20, 2024, in accordance with Swiss law, the Company registered in the commercial register 6,120,000 new shares issued out of conditional capital from December 12, 2023 to December 31, 2023 following the exercise of pre-funded warrants granted to one institutional investor on April 3, 2023.

14. Share-based compensation

The total share-based compensation expense for equity incentive units recognized as continuing operating costs in the statements of profit or loss for the three-month and nine-month periods ended September 30, 2025 amounted to CHF 15,106 and CHF 59,204 respectively (CHF 38,450 and CHF 144,023 for the three-month and nine-month periods ended September 30, 2024).

The total share-based compensation expense for equity incentive units recognized as discontinued operating costs in the statements of profit or loss under “net profit or loss from discontinued operations” amounted to CHF 1,485,750 for the nine-month period ended September 30, 2024 of which CHF 1,158,069 related to the accelerated vesting of equity incentive units of employees and Executive Managers transferred to Neurosterix Pharma Sàrl and included in the net gain of the sale of activities (note 21).

As of September 30, 2025, 7,986,451 options were outstanding (December 31, 2024: 8,006,791). As of September 30, 2025, 29,904,690 shares benefiting from our Deferred Strike Price Payment Plan (DSPPP) were outstanding (respectively 29,950,268 shares as of December 31, 2024). All the shares benefiting from our DSPPP have been recorded as treasury shares in accordance with IFRS 2 (note 13).

Addex Therapeutics │ Unaudited Interim Condensed Consolidated Financial Statements │Notes

15. Retirement benefits obligations

The amounts recognized in the statements of profit or loss are as follows:

The Group’s pension costs recognized as continuing operating costs in the statement of profit or loss for the three-month and the nine-month periods ended September 30, 2025, amounted to CHF 8,062 and CHF 24,183, respectively (CHF 3,390 and CHF 9,098 for the three-month and nine-month periods ended September 30, 2024).

During the nine-month period ended September 30, 2024, the Group recognized a pension cost of CHF 42,493 as discontinued operations in the statements of profit or loss under “net profit or loss from discontinued operations” relating to the employees transferred to Neurosterix Group on April 2, 2024. As part of the transaction, a gain of CHF 433,791 was recognized in the statements of profit or loss under “net profit or loss from discontinued operations” as net gain related to the sale of activities due to a positive past service cost generated by the transfer of employees to Neurosterix Group (note 21).

The amounts recognized in the balance sheet are determined as follows:

Retirement benefit obligation remained stable at CHF 0.2 million as of September 30, 2025 compared to December 31, 2024.

16. Revenue from contract with customer

License & research agreement with Indivior PLC

On January 2, 2018, the Group entered into an agreement with Indivior for the discovery, development and commercialization of novel GABAB PAM compounds for the treatment of addiction and other CNS diseases. This agreement included the selected clinical candidate, ADX71441. In addition, Indivior agreed to fund a research program at the Group to discover novel GABAB PAM compounds.

The contract contains two distinct material promises and performance obligations: (1) the selected compound ADX71441 which falls within the definition of a licensed compound, whose rights of use and benefits thereon was transferred in January 2018 and, (2) the research services to be conducted by the Group and funded by Indivior to discover novel GABAB PAM compounds for clinical development that may be discovered over the research term of the agreement and selected by Indivior.

Indivior has sole responsibility, including funding liability, for development of selected compounds under the agreement through preclinical and clinical trials, as well as registration procedures and commercialization, if any, worldwide. Indivior has the right to design development programs for selected compounds under the agreement. Through the Group’s participation in a joint development committee, the Group reviews, in an advisory capacity, any development programs designed by Indivior. However, Indivior has authority over all aspects of the development of such selected compounds.

Under terms of the agreement, the Group granted Indivior an exclusive license to use relevant patents and know-how in relation to the development and commercialization of product candidates selected by Indivior. Subject to agreed conditions, the Group and Indivior jointly own all intellectual property rights that are jointly developed and the Group or Indivior individually own all intellectual property rights that the Group or Indivior develop individually. The Group has retained the right to select compounds from the research program for further development in areas outside the interest of Indivior including chronic cough. Under certain conditions, but subject to certain consequences, Indivior may terminate the agreement.

Addex Therapeutics │ Unaudited Interim Condensed Consolidated Financial Statements │Notes

In January 2018, the Group received, under the terms of the agreement, a non-refundable upfront fee of USD 5.0 million for the right to use the clinical candidate, ADX71441, including all materials and know-how related to this clinical candidate. In addition, the Group is eligible for payments on successful achievement of pre-specified clinical, regulatory and commercial milestones totaling USD 330 million and royalties on net sales of mid-single digits to low double-digits. On February 14, 2019, Indivior terminated the development of their selected compound, ADX71441. Separately, Indivior funds research at the Group, based on a research plan to be mutually agreed between the parties, to discover novel GABAB PAM compounds. These future novel GABAB PAM compounds, if selected by Indivior, become licensed compounds. The Group agreed with Indivior to an initial research term and duration of two years with a funding of USD 4 million over the period for the Group’s R&D costs incurred, that can be extended by twelve-month increments. R&D costs are calculated based on the costs incurred in accordance with the contract. Following Indivior’s selection of one newly identified compound, the Group has the right to also select one additional newly identified compound. The Group is responsible for the funding of all development and commercialization costs of its selected compounds and Indivior has no rights to the Group’s selected compounds. The initial two-year research term was expected to run from May 2018 to April 2020. In 2019, Indivior agreed to an additional research funding of USD 1.6 million, for the research period. On October 30, 2020, the research term was extended until June 30, 2021 and Indivior agreed to additional research funding of USD 2.8 million. Effective May 1, 2021, the research term was extended until July 31, 2022 and Indivior agreed additional research funding of CHF 3.7 million, of which CHF 2.7 million was paid to the Group and CHF 1.0 million paid directly by Indivior to third party suppliers that are supporting the funded research program. In August 2022, the research agreement was extended until March 31, 2023 and Indivior agreed to additional research funding of CHF 0.85 million. The reserved indications, where Addex retains exclusive rights to develop its own independent GABAB PAM program, have also been expanded to include chronic cough. Effective November 1, 2022, the research term was extended until June 30, 2023 and Indivior agreed to additional research funding of CHF 0.95 million. Effective July 1, 2023, the research agreement with Indivior has been extended until June 30, 2024 and Indivior committed additional research funding of CHF 2.7 million including CHF 1.1 million paid to the Group and CHF 1.6 million paid directly by Indivior to third party suppliers that are supporting the funded research program. On August 27, 2024, Indivior selected a compound for future development in substance use disorder and undertakes all future development of their selected compound. Under the terms of the agreement, the Group has also exercised its right to select a compound to advance its own independent GABAB PAM program for the treatment of chronic cough.

For the three-month and nine-month periods ended September 30, 2025, the Group recognized revenue of CHF 29,724 (CHF 36,502 and CHF 92,618 for the three-month and nine-month periods ended September 30, 2024) related to the maintenance of patents licensed to indivior under the licensing and research agreement entered into in 2018. During the nine-month period ended September 30, 2024, the Group recognized CHF 0.3 million as revenue related to the research agreement that has been completed during the second half of 2024.

Janssen Pharmaceuticals Inc. (formerly Ortho-McNeil-Janssen Pharmaceuticals Inc)

On December 31, 2004, the Group entered into a research collaboration and license agreement with Janssen Pharmaceuticals Inc. (JPI). In accordance with this agreement, JPI has acquired an exclusive worldwide license to develop mGlu2 PAM compounds for the treatment of human health.

In 2024, Janssen completed a Phase 2a proof of concept clinical trial of ADX71149 in epilepsy patients that did not achieve statistical significance for the primary endpoint of time for patients to reach baseline seizure count when ADX71149 was added to standard of care and decided to terminate the development of ADX71149. On April 17, 2025, the Group announced that the license agreement had been terminated and the program and all related intellectual property has been returned to the Group.

Under the terms of the Janssen agreement the Group was eligible to receive up to EUR 109 million in success-based development and regulatory milestone, and low double-digit royalties on net sales.

No amounts have been recognized under this agreement for the nine-month period ended September 30, 2025 and 2024.

17. Other income

During the nine-month period ended September 30, 2025, the Group recognized CHF 0.1 million primarily related to the fair value of services received from Neurosterix Group at zero cost (note 10). The income from IT consultancy agreements recognized during the nine-month periods ended September 30, 2024 and 2025 was close to nil.

In September 2023, the Group was awarded a grant of CHF 0.5 million by Eurostars/Innosuisse to support the mGlu2 NAM program of which CHF 0.3 million were received in December 2023. The Group recognized CHF 38,401 from January 1, 2024 to April 2, 2024, the date when the program was transferred to Neurosterix Pharma Sàrl and recorded as discontinued operations (note 21). The remaining funds and deferred income of CHF 0.3 million recorded as assets and liabilities held for sale as of April 2, 2024, has been transferred to Neurosterix Pharma Sàrl.

Addex Therapeutics │ Unaudited Interim Condensed Consolidated Financial Statements │Notes

18. Operating costs

The evolution of the total operating costs of continuing operations is mainly driven by professional fees, staff costs and external research and development costs.

During the nine-month period ended September 30, 2025, total operating costs recognized as continuing operating costs decreased by CHF 0.5 million compared to the same period ended September 30, 2024, primarily due to decrease external research and development costs of CHF 0.3 million.

During the three-month period ended September 30, 2025, total operating costs recognized as continuing operating costs increased by CHF 0.1 million compared to the same period ended September 30, 2024, primarily due to increased professional fees of CHF 0.1 million.

Total operating costs recognized as discontinued operations, primarily related to staff costs and external research and development, amounted to CHF 2.0 million for the nine-month period ended September 30, 2024 (note 21).

19. Staff costs

During the nine-month period ended September 30, 2025, total staff costs recognized as continuing operating costs remained stable at CHF 0.2 million compared to the same period ended September 30, 2024.

Staff costs recognized as discontinued operations amounted to CHF 1.4 million for the nine-month period ended September 30, 2024 (note 21).

20. Finance result, net

Addex Therapeutics │ Unaudited Interim Condensed Consolidated Financial Statements │Notes

21. Discontinued operations

On February 8, 2024, the Group signed a non-binding term sheet with Perceptive Advisors related to the divestment of part of its business. On April 2, 2024, the sale became effective. The allosteric modulator drug discovery technology platform and a portfolio of preclinical programs have been divested to a new Swiss company, Neurosterix Pharma Sàrl that has received committed funding of USD 65 million from a syndicate of investors led by Perceptive Advisors (Perceptive Xontogeny Venture Fund II L.P, Perceptive Life Sciences Master Fund Ltd and Acorn Bioventures 2, L.P) (the “Neurosterix Transaction” or “Transaction”) from April 2, 2024 to the issuance date of these unaudited condensed consolidated financial statements. The Group received gross proceeds of CHF 5.0 million in cash and an equity interest representing 20% of Neurosterix US Holdings LLC (note 1). The Group retained its partnerships with Janssen Pharmaceuticals, Inc. and Indivior PLC, as well as unpartnered clinical stage assets including dipraglurant for Parkinson’s disease and post-stroke/TBI recovery and its preclinical GABAB PAM program for chronic cough. The Transaction includes the transfer of the associated R&D staff and infrastructure. As part of the Transaction, the Group and Neurosterix Pharma Sàrl entered into a service agreement which provides the Group with access to certain staff and infrastructure at zero cost to ensure the operation of the Group retained business until December 31, 2024. As of January 1, 2025, the agreement was not formally renewed. However, Neurosterix agreed to provide the Group with access to certain employees and infrastructure at zero cost. (note 10).

As the allosteric modulator drug discovery technology platform and a portfolio of preclinical programs have been sold on April 2, 2024, such activities have been identified as discontinued operations for the period beginning on January 1, 2024 and terminating on April 1, 2024. The net gain of the sale of activities amounted to CHF 13,959,500 during the nine-month period ended September 30, 2024. During the same period ended September 30, 2025, the Group recognized an additional discontinued gain of CHF 117,747 from the sale of activities, related to a consideration receivable considered as contingent during previous periods. As of September 30, 2025, there is not any remaining contingent consideration receivable.

Financial performance of discontinued operations:

Operating costs of discontinued operations:

Addex Therapeutics │ Unaudited Interim Condensed Consolidated Financial Statements │Notes

Cash flows of discontinued operations:

Details of the net gain of the sale of activities: