Paris, May 06, 2020, 2pm

AB Science granted authorization by French Medicine Agency (ANSM) to initiate Phase 2 study evaluating masitinib in combination with isoquercetin? for the treatment of COVID-19

Company to host live webcast on Monday May 11, 2020, 5.30pm CET

AB Science SA?(NYSE Euronext - FR0010557264 - AB) today announces initiation of a Phase 2 study evaluating masitinib in combination with isoquercetin for the treatment of COVID-19, following rapid review and acceptance received from the French Medicine Agency, ANSM.

This study (AB20001) is a randomized (1:1), open-label Phase 2 clinical trial to evaluate the safety and efficacy of masitinib combined with isoquercetin in hospitalized patients with moderate and severe COVID-19.

The study will enroll 200 patients (age =18 without an upper age limit) at medical centers in France and other countries. The primary objective is to improve the clinical status of patients after 15 days of treatment.

A webcast call will be held on Monday May 11, 2020 at 5.30pm CET to present the detailed study design and further explain the scientific rationale for combining masitinib with isoquercetin.

Dial-in & webcast information will be provided later.

Many patients with moderate and severe COVID-19, develop a ?cytokine storm? that leads to severe pulmonary inflammation and various thrombotic events associated with acute respiratory distress syndrome (ARDS) and potentially death. The combination of masitinib and isoquercetin may prevent the development of these two complications.

• masitinib is a potent blocker of mast cells and macrophages that are contributors to the cytokine storm
• isoquercetin inhibits disulfide isomerase (PDI), an enzyme directly involved in the formation of clots and decreases D-Dimer, a predictor of COVID-19 thrombosis severity.
• the combination of masitinib and isoquercetin has a synergistic effect against senescent cells, a potential target of the virus that could explain the higher mortality rates in the elderly.

Pascal Chanez, Professor of Respiratory Medicine at the AP-HM and Aix Marseille University at Marseille, France and principal investigator said ?The combination of masitinib with isoquercetin is based on a strong scientific rationale and offers a differentiated strategy. On the one hand, masitinib and isoquercetin have upstream activity to prevent cytokine storm and its associated lung injuries and thrombosis, and on the other hand, the combination has a totally innovative synergistic effect to target the senescent cells, which could protect the most vulnerable aged population. The enrolment of patients in this study will primarily come from the second wave of the disease?.

About the study primary endpoint

The 7-point ordinal scale for clinical status is: 1. Not hospitalized, no limitations on activities; 2.Not hospitalized, limitation on activities; 3. Hospitalized, not requiring supplemental oxygen; 4. Hospitalized, requiring supplemental oxygen; 5. Hospitalized, on non-invasive ventilation or high flow oxygen devices; 6. Hospitalized, on invasive mechanical ventilation or ECMO; 7. Death.

About masitinib Masitinib 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 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, and inflammatory diseases. The company is headquartered in Paris, France, and listed on Euronext Paris (ticker: AB).

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 filed by AB Science with the Autorit? des March?s Financiers (AMF), including those listed in the Chapter 4 "Risk Factors" of AB Science reference document filed with the AMF on November 22, 2016, under the number R. 16-078. 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.

AB Science Financial Communication & Media Relations investors@ab-science.com

Attachment

• Authorisation phase 2 Covid vEng VF