AB Science announces a voluntary hold in the clinical studies of masitinib worldwide

PRESS RELEASE

AB SCIENCE ANNOUNCES A VOLUNTARY HOLD IN THE CLINICAL STUDIES OF MASITINIB WORLDWIDE

Paris, June 1st, 2021, 7am

AB Science SA (Euronext - FR0010557264 - AB) announced today that it has taken the decision to suspend inclusions and treatment initiation in its clinical studies with masitinib worldwide. This decision follows consultation with the French regulatory authorities (ANSM) and other regulatory agencies. This decision is relevant to three studies: phase 3 in mastocytosis (AB15003), phase 3 in amyotrophic lateral sclerosis (AB19001) and phase 2 in COVID (AB20001). To this end, AB Science has filed or will file without delay a request for a temporary study hold in all countries where these studies are ongoing.

AB Science has identified a potential risk of ischemic heart disease with masitinib. This signal was detected in a retrospective analysis of controlled and unblinded studies of masitinib. Following its own internal procedures, AB Science has decided to suspend inclusion in ongoing studies with masitinib until the investigation of this potential safety issue is finished. AB Science is working closely with the ANSM and other regulatory agencies to complete the necessary additional analyses.

Patient safety is our priority. AB Science is committed to continue the development of masitinib in the indications initiated, while ensuring patient safety. AB Science is working in full collaboration with the regulatory authorities in order to resume patient enrollment in these studies.

About masitinibMasitinib is a new 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.

About AB ScienceFounded 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: www.ab-science.com.

Forward-looking Statements - AB ScienceThis 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 ScienceFinancial Communication & Media Relations investors@ab-science.com

Media Relations – USA

RooneyPartnersKate Barrettekbarrette@rooneyco.com

+1 646 432 0191

Media Relations – France

NewCapArthur Rouilléarouille@newcap.fr

+33 (0)1 44 71 00 15

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