ADDEX THERAPEUTICS LTD INDEX TO UNAUDITED CONDENSED CONSOLIDATED FINANCIAL STATEMENTS Consolidated Financial Statements Unaudited Condensed Consolidated Balance Sheets as at

ADDEX THERAPEUTICS LTD

INDEX TO UNAUDITED CONDENSED CONSOLIDATED FINANCIAL STATEMENTS

ADDEX THERAPEUTICS LTD

Unaudited Condensed Consolidated Balance Sheets

as at June 30, 2020 and December 31, 2019

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

ADDEX THERAPEUTICS LTD

Unaudited Condensed Consolidated Statements of Comprehensive Loss

for the three-month and six-month periods ended June 30, 2020

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

ADDEX THERAPEUTICS LTD

Unaudited Condensed Consolidated Statements of Changes in Equity

For the six-month period ended June 30, 2020

Amounts in Swiss francs

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

ADDEX THERAPEUTICS LTD

Unaudited Condensed Consolidated Statements of Changes in Equity

For the three-month period ended June 30, 2020 (1/2)

Amounts in Swiss francs

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

ADDEX THERAPEUTICS LTD

Unaudited Condensed Consolidated Statements of Changes in Equity

For the three-month period ended June 30, 2020 (2/2)

Amounts in Swiss francs

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

ADDEX THERAPEUTICS LTD

Unaudited Condensed Consolidated Statements of Cash Flows

for the six-month period ended June 30, 2020

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

Addex Therapeutics | 2020 Condensed Consolidated Interim Financial Statements | Notes

(Amounts in Swiss francs)

1. General information

Addex Therapeutics Ltd (the Company ), formerly Addex Pharmaceuticals Ltd, and its subsidiaries (together, the Group ) comprise a clinical stage pharmaceutical group applying its leading allosteric modulator drug discovery platform to discovery and development of small molecule pharmaceutical products, with an initial focus on central nervous system disorders.

The Company is a Swiss stockholding corporation domiciled c/o Addex Pharma SA, Chemin des Aulx 12, CH1228 Plan-les-Ouates, Geneva, Switzerland and the parent company of Addex Pharma SA, Addex Pharmaceuticals France SAS and Addex Pharmaceuticals Inc., which company incorporated on May 29, 2019 in Delaware with its principal business location in San Francisco, California, United States. The Company s registered ordinary shares are traded on SIX, Swiss Exchange, under the ticker symbol ADXN . On January 29, 2020, the Group listed on the Nasdaq Stock Market, American Depositary Shares (ADSs) under the symbol ADXN without a new issuance of securities. ADSs represent interests in the Company s outstanding ordinary shares.

These condensed consolidated financial statements have been approved for issuance by the Board of Directors on August 11, 2020.

2. Basis of preparation

These condensed consolidated interim financial statements for the three month and six month periods ended June 30, 2020, 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, 2019.

The preparation of financial statements 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 condensed consolidated interim financial statements are disclosed in note 4 to the consolidated financial statements for the year ended December 31, 2019.

A number of new or amended standards and interpretations became applicable for financial periods beginning on or after January 1, 2020. The Group noted that the latter did not have a material impact on the Group s financial position or disclosures made in the condensed consolidated interim financial statements.

Due to rounding, numbers presented throughout these condensed consolidated financial statements may not add up precisely to the totals provided. All ratios and variances are calculated using the underlying amount rather than the presented rounded amount.

3. Critical 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:

The Group s accounts are prepared on a going concern basis. To date, the Group has financed its cash requirements primarily from share issuances and licensing certain of its research and development stage products. The Group is a development stage enterprise and is exposed to all the risks inherent in establishing a business. The Group maintains

Addex Therapeutics | 2020 Condensed Consolidated Interim Financial Statements | Notes

detailed financial forecasts and monitors actual results on a regular basis so that measures can be taken to ensure the Group remains solvent.

In early 2020 a coronavirus disease (COVID-19) pandemic developed globally resulting in a significant number of infections and negative effects on economic activity. The Group is actively monitoring the situation and is taking any necessary measures to respond to the situation in cooperation with the various stakeholders. On March 18, 2020 the Group announced the suspension of the initiation of a placebo-controlled Phase 2b/3 pivotal clinical trial of dipraglurant in levodopa-induced dyskinesia associated with Parkinson s disease (dipraglurant PD-LID). Depending on the duration of the COVID-19 crisis and continued negative impact on global economic activity, the Group may have to take additional measures that will have a negative impact on the Group s business continuity and may experience certain liquidity restraints as well as incur impairments on its assets. The exact impact on the Group s activities in the short and medium terms cannot be reasonably predicted. However, based on the risk mitigation measures undertaken, the Group concluded that there is no material uncertainty that may cast a significant doubt upon the Group s ability to continue as a going concern.

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 15.

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 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.

To date, the Group has not experienced significant changes in the estimates of accrued research and development expenses after a reporting period. However, due to the nature of estimates, the Group may be required to make changes to the estimates in the future as it becomes aware of additional information about the status or conduct of its research activities.

Research and development costs

The Group recognizes expenditure incurred in carrying out its research and development activities, including development supplies, until it becomes probable that future economic benefits will flow to the Group, which results in recognizing such costs as intangible assets, involving a certain degree of judgement. Currently, such development supplies are associated with preclinical and clinical trials of specific products that do not have any demonstrated technical feasibility.

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.

Addex Therapeutics | 2020 Condensed Consolidated Interim Financial Statements | Notes

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.

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

5.1 Reportable segments

The Group operates in one segment, which is the business of developing drugs for human health.

5.2 Entity wide information

Information about products, services and major customers

External income of the Group for the three-month and six-month periods ended June 30, 2020 and 2019 is derived from the business of discovery development and commercialization of pharmaceutical products. Income was earned from the sale of license rights and rendering of research services to a pharmaceutical company and grants earned.

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 15, Revenue from contract with customer and note 16 Other income .

Addex Therapeutics | 2020 Condensed Consolidated Interim Financial Statements | Notes

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

The capital expenditure during the six-month period ended June 30, 2020 is CHF 10,633 (CHF 22,465 for the six-month period ended June 30, 2019).

The geographical analysis of operating costs is as follows:

6. Cash and cash equivalents

The Group pays interest on CHF cash and cash equivalents and earns interest on USD cash and cash equivalents. The Group invests its cash balances into a variety of current and deposit accounts with Swiss banks. In addition, the Group invests a portion of its USD cash in line with its treasury guidelines. As of June 30, 2020, non-used funds received from Eurostars/Innosuisse amount to CHF 219,973 (note 16).

All cash and cash equivalents were held either at bank or on hand as at June 30, 2020 and December 31, 2019.

7. Other current assets

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 contract assets. As of June 30, 2020, the receivables were comprised of five non-governmental debtors whose combined outstanding balances were CHF 29,727 (five non-governmental debtors for CHF 88,075 as of December 31, 2019). The Group has considered these customers to have a low risk of default based on historic loss rates and forward-looking information on macroeconomic factors affecting the ability of the customers to settle the receivables. As a result, excepted loss allowance has been deemed as nil as of June 30, 2020 and December 31, 2019.

The prepayments mainly relate to contract research organization and directors and officer s liability insurances. The increase of the prepayments is because the insurance premiums are paid at the beginning of the year.

Addex Therapeutics | 2020 Condensed Consolidated Interim Financial Statements | Notes

8. Right-of-use assets

9. Property, plant and equipment