PRESS RELEASE AB SCIENCE PRESENTS ITS FINANCIAL INFORMATION AS OF DECEMBER 31, 2023 AND THE KEY EVENTS OF THE PERIOD Clinical development Continuation of the conditional marketing authorisation application procedures with the European Medicines Agency (EMA) and Health Canada for masitinib in the treatment of amyotrophic lateral sclerosis (ALS) First complete bone marrow response in an acute myeloid leukemia patient in its AB8939 Phase I/II clinical trial New clinical development program for masitinib in sickle cell disease, among the winning projects to be funded under the sixth call for "Hospital-University Research in Health" (Recherche Hospitalo-Universitaire en santé) projects, part of the Future Investments Program Strengthening of intellectual property protection for masitinib in ALS, mastocytosis and prostate cancer Financial information and other corporate information Consolidated operating loss of €13.4 million as of 31 December 2023, compared with a loss of €15.9 million as of 31 December 2022, a decrease of the operating loss of €2.5 million (15.7%) Cash position of €6.1 million as of 31 December 2023, plus a cash contribution of €4.9 million for the research tax credit for the years 2020 and 2021 paid in 2024, and an estimated amount of 3.0 million euros for the research tax credit for the year 2022 to be received in the first half of 2024, as well as the payment or mobilisation of the research tax credit for the year 2023 to be received in the second half of 2024. The difference between the planned initial amount of research tax credit and the amount paid is currently under discussion with the tax administration Clinical development strategy based on two platforms: the late-stage masitinib clinical phase 3 platform and the new microtubule platform in clinical Phase 1 Renewal of the Programme d'Augmentation de Capital à Terme (PACT) concluded with Alpha Blue Ocean and subscription by Alpha Blue Ocean of a tranche of one million shares Coverage initiation by DNA Finance and In Extenso Finance   Paris, May 15, 2024, 8pm CET AB Science SA (Euronext - FR0010557264 - AB) today reports its revenues for the year 2023 and provides an update on its activities. CLINICAL DEVELOPMENT KEY EVENTS DURING THE YEAR 2023 AND SINCE DECEMBER 31, 2023 Continuation of the conditional marketing authorisation application procedure with the European Medicines Agency (EMA) for masitinib in the treatment of amyotrophic lateral sclerosis (ALS) In August 2022, AB Science announced that it had submitted a conditional marketing authorisation application to the European Medicines Agency (EMA) for masitinib in the treatment of amyotrophic lateral sclerosis (ALS). This procedure continued in 2023. In January 2024, AB Science announced that the Committee for Medicinal Products for Human Use (CHMP) had proposed that AB Science respond in writing to the outstanding questions at D195 of the procedure, instead of addressing these questions at the Oral Explanation. AB Science accepted this proposal. A new Oral Explanation is not mandatory and will only be scheduled if major objections remain after the review of the written responses. AB Science now expects an opinion from the CHMP before the end of the second quarter of 2024. Continuation of the Notice of Compliance with Conditions procedure with Health Canada for masitinib in the treatment of amyotrophic lateral sclerosis (ALS) In February 2022, AB Science announced that it had submitted a conditional marketing authorization application to Health Canada for masitinib in the treatment of amyotrophic lateral sclerosis (ALS). This procedure continued in 2023. AB Science announced in February 2024 that Health Canada had issued a Notice of Deficiency-Withdrawal (NOD/w) regarding the submission file for masitinib in the treatment of ALS and indicated its intention to file a request for reconsideration of the file. In April 2024, AB Science announced that Health Canada had deemed the request for reconsideration of masitinib eligible. The reconsideration process will re-assess, with new reviewers, the decision on the basis of the data in the initial dossier. Health Canada and AB Science have met to discuss the reconsideration process. AB Science is working closely with the Agency to facilitate the review of the conditional approval of masitinib in ALS. First complete bone marrow response in an acute myeloid leukemia patient in its AB8939 Phase I/II clinical trial AB Science announced in March 2023 a case report from the initial stage of its Phase I/II study (AB18001) evaluating AB8939, a microtubule destabilizer, in patients with refractory and relapsed acute myeloid leukemia (AML). The AML patient in question was in failure to prior treatment with azacitidine and presented with a MECOM gene rearrangement, which is a biomarker for resistance to standard chemotherapies that is associated with a high-risk of disease progression and inferior prognosis. One month after the first treatment cycle (i.e., three consecutive days of AB8939 treatment) there was a drastic reduction in bone marrow blast cells (i.e., leukemia cells), from a pretreatment level of 55% to 5% (i.e., a morphologic leukemia free state). Remarkably, this response was achieved at a very low dose of AB8939, corresponding to the second step of dose increment (out of 13 potential steps) in phase I. The patient also showed good tolerance to AB8939, having experienced no treatment-related toxicities. At the request of the investigator, AB Science has authorized further treatment cycles of AB8939 to this patient. One month after the second treatment cycle of three consecutive days at this dose, a good response has been maintained with bone marrow blasts being at 10% (corresponding to a 5-fold reduction relative to baseline). A third treatment cycle for this patient has been initiated. New clinical development program for masitinib in sickle cell disease, among the winning projects to be funded under the sixth call for "Hospital-University Research in Health" (Recherche Hospitalo-Universitaire en santé) projects, part of the Future Investments Program AB Science announced that a new clinical development program for masitinib in sickle cell disease is among the winning projects to be funded under the sixth call for "Hospital-University Research in Health" (Recherche Hospitalo-Universitaire en santé) projects, which is part of the Future Investments Program. The "Hospital-University Research in Health" (RHU) call for projects of the Future Investments Program, operated by the National Research Agency, aims to support innovative and large-scale research projects in the field of health. Focused on translational research, i.e., converting results in basic research into results that directly benefit humans, RHU projects involve academic, hospital, and business stakeholders. As part of this call for projects, the SICKMAST project, funded with 9.2 million euros, aims to: First, identify and validate, from a database of 1500 patients (including 700 already identified), biomarkers highlighting the role of mast cells and basophils in orchestrating acute and chronic complications of sickle cell disease. Second, demonstrate in a phase 2 clinical trial the efficacy of masitinib in the treatment of acute and chronic complications of sickle cell disease in patients identified based on biomarkers. The Assistance Publique-Hôpitaux de Paris (AP-HP) will be the promoter of these phase 2 studies. AB Science will mainly be involved in supplying masitinib and monitoring masitinib pharmacovigilance data. AB Science remains free to carry out, as it sees fit, any potential phase 3 development following the success of phase 2. A new patent has been filed, which, if granted, will extend the international protection of masitinib in sickle cell disease until 2040. As part of the consortium agreement established for its patents, AB Science will pay royalties to AP-HP in the event of commercialization of masitinib in sickle cell disease. Strengthening of intellectual property protection for masitinib in ALS, mastocytosis and prostate cancer In ALS, AB Science announced that announced that the patent Office of Japan and the patent Office of Canada and have issued a Notice of Allowance (NOA) for a patent relating to methods of treating amyotrophic lateral sclerosis (ALS) with its lead compound masitinib. These new patents provide strong protection for masitinib in the treatment of ALS until 2037 and completes the IP coverage for ALS across all key geographic areas where masitinib could be marketed. In mastocytosis, AB Science announced that the European Patent Office has issued a Notice of Allowance for a patent relating to methods of treating severe systemic mastocytosis (i.e. a medical use patent) with masitinib. This new European patent provides intellectual property protection for masitinib in this indication until October 2036. In prostate cancer, AB Science announced that the European Patent Office has issued a Notice of Allowance for a patent relating to methods of treating (mCRPC) with masitinib, based on findings from study AB12003. This new European patent provides intellectual property protection for masitinib in the treatment of mCRPC until 2042. The same medical use patent strategy is being pursued in other indications such as multiple sclerosis and Alzheimer's disease for protection until 2041. CONSOLIDATED FINANCIAL INFORMATION FOR THE YEAR 2023 The operating result as of 31 December 2023 was a loss of €13,429k, compared with a loss of €15,937k as of 31 December 2022, a decrease in the operating loss of €2,508k (15.7%). Operating income, exclusively made up of revenues related to the operation of a drug in veterinary medicine, amounted to €970k as of 31 December 2023, compared to €958k a year earlier. Operating expenses decreased by 14.8% between the years ended 31 December 2023 and 2022. This decrease is mainly due to lower research and development costs (down 21.5%). Marketing expenses were stable compared to 31 December 2022, rising from €480k as of 31 December 2022 to €522k as of 31 December 2023. Administrative expenses were stable compared to 31 December 2022, decreasing from €3,040k as of 31 December 2022 to €3,017k as of 31 December 2023. Research and development costs decreased by €2,868k, or 21.5%, from €13,3453k as of 31 December 2022 to €10,477k as of 31 December 2023. Net financial income for the years ended 31 December 2022 and 31 December 2023 was €2,326k and €3,382k respectively. In 2023, as in 2022, this financial result has no cash impact. The financial result of €3,382k includes income of €4,169k (versus €3,165k in 2022) resulting from the valuation of these financial instruments, and a financial expense of €1,598k (versus €1,510k in 2022), of which €941k corresponds to the provision for capitalised interest relating to the loan with the EIB. The consolidated net loss as of 31 December 2023 is €10,048k compared to a loss of €13,615k as of 31 December 2022, a decrease of 26.2%. The following table summarizes the ...