Risk factors

We refer to the description of risk factors in the 2015 Annual Report, pp. 53-59, as supplemented by the description of risk factors in the annual report on Form 20-F filed with the U.S. Securities and Exchange Commission, pp. 5-45. In summary, the principal risks and uncertainties faced by us relate to: our financial position and need for additional capital; product development, regulatory approval and commercialization; our reliance on third parties; our competitive position; our intellectual property; our organization, structure and operation (including but not limited to certain risks related to our status as a U.S. publicly listed company following the public offering of shares (in the form of ADSs) and listing on NASDAQ in May 2015) and market risks relating to our shares and ADSs.

We also face a risk related to the accounting treatment under IFRS for the Share Subscription Agreement for the Gilead transaction. We refer to the note on significant judgement applied in that respect included in the 2015 Annual Report. After careful analysis of the contract and the applicable IFRS literature, management has judged that it was appropriate to account for this transaction as a derivative financial asset with variances in fair value through the income statement between entering into the transaction (16 December 2015) and the date of closing the transaction (19 January 2016). Our statutory auditor has audited this significant transaction and agreed with the position taken by management. In the framework of the preparation of the listing prospectus for the shares issued following this transaction, the FSMA reviewed the draft prospectus and our annual accounts for the year ended 31 December 2015 including the accounting for the Share Subscription Agreement under IFRS. The FSMA concluded that, taking into account the complexity of the questions and the lack of specific authoritative literature, it should first seek the advice from the European Securities and Markets Authority via its European Enforcers Coordination Sessions (EECS) forum, a forum in which all EU National Enforcers of financial information meet to exchange views and discuss experiences of enforcement of IFRS to arrange for consistent application of IFRS in judgmental areas across the jurisdictions. On the date of this report, no advice from EECS has been received yet. It is currently uncertain whether the European supervisory authorities will require a change in the way the share subscription part of the Gilead transaction was accounted for in our audited financial statements for the year ended 31 December 2015 and our unaudited interim financial statements for Q1 2016 included in this report. The final decision would not affect our cash position or cash flows.

We also refer to the description of the Group's financial risk management given in the 2015 Annual Report, pp. 131-134, which remains valid.