PDGFRα x c-Kit x PDGFRβ x LYN

PRESS RELEASE AB SCIENCE PROVIDES AN UPDATE ON THE APPLICATION FOR CONDITIONAL MARKETING AUTHORISATION OF MASITINIB IN THE TREATMENT OF AMYOTROPHIC LATERAL SCLEROSIS Paris, 17 October, 2024, 7.30pm CET AB Science SA (Euronext - FR0010557264 - AB) today announces that the European Medicines Agency (EMA) confirmed a negative opinion for the conditional marketing authorization of masitinib in the treatment of amyotrophic lateral sclerosis (ALS), following a vote adopted during the Committee for Medicinal Products for Human Use (CHMP) meeting on 14-17 October 2024. The Conditional Marketing Authorization of masitinib had been under review by the CHMP in response to the company’s request for a re-examination of the negative opinion issued in June 2024. Despite the difficulty of a conditional marketing authorization in ALS, AB Science had asked for a re-examination first and foremost considering the urgent need for patients to have early access to a promising treatment and the clinical data obtained from the first study AB10015, showing an increase in median overall survival of + 6 months (p= 0.0761) in the primary analysis population of Normal progressors, and a significant + 12 months survival benefit (p=0.0192) in a subgroup defined as patients prior to any complete loss of function (i.e. excluding patient with an ALSFRS-R score of 0 in any of the 12 items of the scale). A Scientific Advisory Group – Neurology (SAG-N) was conveyed for the first time, as part of the re-examination procedure. Importantly, the SAG-N experts agreed with the categorization approach to distinguish between Normal and Fast Progressors (and with the 1.1 points per month ALSFRS decline from onset as cut-off), if properly pre-specified. This opinion supports the design of the confirmatory study of masitinib in ALS, as the same dichotomization and the same cut-off have been pre-specified for the confirmatory study. The phase 2B/3 study AB10015 is considered hypothesis generating but not sufficient as a single pivotal study to support a marketing authorization. Separately, Health Canada recently informed AB Science that key analyses presented for the reconsideration submitted in May 2024 [1], have been considered as new data, rather than re-analyses of existing data. Considering that Health Canada guideline prevent the use of new data as part of the re-examination procedure, AB Science has decided to notify Health Canada it will not pursue the reconsideration. Health Canada has offered the possibility to submit a new application to resolve this issue. Alain Moussy, CEO and co-founder of AB Science said “ We are thankful to the patients and physicians that supported the re-examination process as part of the EMA review. We did all these efforts for the patients. We are convinced that masitinib is a promising drug when we see patients from the study surviving with the drugs for more than 10 years in our compassionate use program. Now AB Science objective is to focus on the confirmatory phase 3 program of masitinib in ALS to reach full approval ”. References [1] AB Science press release dated 3 April 2024 About AB Science Founded in 2001, AB Science is a pharmaceutical company specializing in the research, development and commercialization of protein kinase inhibitors (PKIs), a class of targeted proteins whose action are key in signaling pathways within cells. Our programs target only diseases with high unmet medical needs, often lethal with short term survival or rare or refractory to previous line of treatment. AB Science has developed a proprietary portfolio of molecules and the Company’s lead compound, masitinib, has already been registered for veterinary medicine and is developed in human medicine in oncology, neurological diseases, inflammatory diseases and viral diseases. The company is headquartered in Paris, France, and listed on Euronext Paris (ticker: AB). Further information is available on AB Science’s website: . Forward-looking Statements - AB Science This press release contains forward-looking statements. These statements are not historical facts. These statements include projections and estimates as well as the assumptions on which they are based, statements based on projects, objectives, intentions and expectations regarding financial results, events, operations, future services, product development and their potential or future performance. These forward-looking statements can often be identified by the words “expect”, “anticipate”, “believe”, “intend”, “estimate” or “plan” as well as other similar terms. While AB Science believes these forward-looking statements are reasonable, investors are cautioned that these forward-looking statements are subject to numerous risks and uncertainties that are difficult to predict and generally beyond the control of AB Science and which may imply that results and actual events significantly differ from those expressed, induced or anticipated in the forward-looking information and statements. These risks and uncertainties include the uncertainties related to product development of the Company which may not be successful or to the marketing authorizations granted by competent authorities or, more generally, any factors that may affect marketing capacity of the products developed by AB Science, as well as those developed or identified in the public documents published by AB Science. AB Science disclaims any obligation or undertaking to update the forward-looking information and statements, subject to the applicable regulations, in particular articles 223-1 et seq. of the AMF General Regulations. For additional information, please contact: AB Science Financial Communication & Media Relations investors@ab-science.com Attachment CP ALS REGUL EMA VENG VF

AB SCIENCE ANNOUNCES ISSUANCE OF A EUROPEAN PATENT FOR MASITINIB IN THE TREATMENT OF SEVERE MASTOCYTOSIS WITH PROTECTION UNTIL 2036 Paris, May 13, 2024, 6pm CET AB Science SA (Euronext - FR0010557264 - AB) today announced that the European patent office has issued a Grant Decision for a patent relating to methods of treating severe mastocytosis with its lead compound masitinib (patent EP 3359195A1). This new European patent provides intellectual property (IP) protection for masitinib in this indication until October 2036 and adds to IP coverage already granted in the USA (US 10045978B2) and Japan (JP 6801892B2). Masitinib is positioned as a treatment of severely symptomatic systemic mastocytosis patients, including the subvariants of indolent and smoldering systemic mastocytosis, who are unresponsive to optimal symptomatic treatment. More specifically, this patent provides protection of masitinib and related compounds for treatment of systemic mastocytosis in a patient population presenting with at least two severe mast cell mediator release associated symptoms, selected from pruritus, flushes or depression (Hamilton rating scale). This patient population is consistent with results from masitinib study AB06006 [1] and also the on-going clinical development program of masitinib in severe systemic mastocytosis. Masitinib has also received orphan drug designation for mastocytosis from both the European Medicines Agency (EMA) and the US Food and Drug Administration (FDA). This orphan drug designation provides 10 and 7 years of market exclusivity in Europe and the United States respectively, subsequent to product approval. The same medical use patent strategy had been successfully pursued in amyotrophic lateral sclerosis, with patent granted worldwide until 2037, and is being pursued in other indications such as multiple sclerosis, Alzheimer’s disease for protection until 2041, and in prostate cancer until 2042. Reference [1] Lortholary O, Chandesris MO, Bulai Livideanu C, et al. Masitinib for treatment of severely symptomatic indolent systemic mastocytosis: a randomised, placebo-controlled, phase 3 study. Lancet. 2017;389(10069):612-620. Indolent systemic mastocytosis (ISM) is a hematological disease characterized by an abnormal number and activation of mast cells in the bone marrow and other organs. The disease if characterized by multiple symptoms that are disabling and can in some cases be life-threatening. Symptoms associated ISM are predominantly associated with neurological disorders (depression, fatigue, cognitive impairment, headache), skin disorders (pruritus, skin lesions), flushing and gastro-intestinal disorders. ISM affects approximately 40,000 people in Europe and 25,000 in the USA. There is currently a high unmet medical need in this population. Masitinib is a orally administered tyrosine kinase inhibitor that targets mast cells and macrophages, important cells for immunity, through inhibiting a limited number of kinases. Based on its unique mechanism of action, masitinib can be developed in a large number of conditions in oncology, in inflammatory diseases, and in certain diseases of the central nervous system. In oncology due to its immunotherapy effect, masitinib can have an effect on survival, alone or in combination with chemotherapy. Through its activity on mast cells and microglia and consequently the inhibition of the activation of the inflammatory process, masitinib can have an effect on the symptoms associated with some inflammatory and central nervous system diseases and the degeneration of these diseases. Founded in 2001, AB Science is a pharmaceutical company specializing in the research, development and commercialization of protein kinase inhibitors (PKIs), a class of targeted proteins whose action are key in signaling pathways within cells. Our programs target only diseases with high unmet medical needs, often lethal with short term survival or rare or refractory to previous line of treatment. AB Science has developed a proprietary portfolio of molecules and the Company’s lead compound, masitinib, has already been registered for veterinary medicine and is developed in human medicine in oncology, neurological diseases, inflammatory diseases and viral diseases. The company is headquartered in Paris, France, and listed on Euronext Paris (ticker: AB). The content above comes from the network. if any infringement, please contact us to modify.