Azacitidine

PRESS RELEASE STONEGATE CAPITAL PARTNERS UPDATES ITS COVERAGE OF AB SCIENCE’S STOCK WITH A DISCOUNTED CASH FLOW VALUATION MID-POINT OF EUR 4.25 PER SHARE Paris, June 2 nd , 2026, 6pm CET AB Science SA (Euronext - FR0010557264 - AB) announces that its stock continues to be covered by Stonegate Capital Partners, a leading independent US-based research and investor outreach firm, which has updated its coverage of the stock following the publication of AB Science’s full year 2025 results, supported by a discounted cash flow valuation with a mid-point of €4.25 per share (range of €3.20 to €5.77 per share). Stonegate Capital Partners issued this update in a research note entitled “Stonegate Capital Partners Updates Coverage on AB Science S.A. (ENXTPA: AB) 1Q26”, published on 26 May 2026. In this update, Stonegate maintained its coverage of the stock, supported by a discounted cash flow model returning a valuation range of €3.20 to €5.77 per share, with a mid-point of €4.25 per share. The update highlights that : AB Science’s strategy now centres on two priorities, masitinib in Amyotrophic Lateral Sclerosis (ALS) and AB8939 in acute myeloid leukemia (AML), reflecting clearer capital allocation. Progressive multiple sclerosis (MS) and Alzheimer’s disease (AD) remain meaningful sources of upside but are now positioned as partnership-led opportunities, given the scale and commercial infrastructure they require. Masitinib remains AB Science’s lead clinical asset in ALS. The confirmatory Phase 3 trial AB23005 is FDA-authorized. The 408-patient, 48-week study evaluates masitinib 4.5 mg/kg/day plus riluzole versus placebo plus riluzole, prospectively targeting normally progressing ALS patients without complete loss of function. In this targeted patient population, AB Science reported a 4.04-point ALSFRS-R benefit, a +20.2% relative CAFS benefit, a 9-month median progression-free survival benefit and a 12-month median overall survival benefit, alongside the identification of a potential plasma biomarker tied to microglia and mast-cell activity. AB8939 is emerging as a visible second pillar, having completed Stage 3 of the AML combination programme (14 days of AB8939 plus venetoclax), with Stage 4 expected to add azacitidine subject to regulatory approval. Early data showed responses in all four treated patients, including one complete remission, one near-complete response and two partial responses, in heavily pre-treated patients with difficult cytogenetics. While still early, these data support continued development in AML populations where resistance and unfavourable genetics remain major unmet needs. On the financing side, AB Science ended FY2025 with €10.2M in cash and added €3.2M through an April 2026 private placement, while its operating loss excluding non-recurring items declined 38% to €3.8M, with creditor deferrals helping to preserve cash for R&D. The Company received a clinical trial financial insurance (CTFI) offer for AB23005, with excess-free coverage of €25M, extendable to €39M, intended to cover clinical-failure costs and provide third-party validation of the Phase 3 design, subject to study funding and premium payment. Stonegate values AB Science using a discounted cash flow model, returning a valuation range of €3.20 to €5.77 per share, with a mid-point of €4.25 per share. Stonegate notes that this framework is currently conservative and that a reduction in the discount rate to approximately 15%, which could be warranted following successful regulatory and operational de-risking, would imply a valuation mid-point of approximately €8.50 per share. This update confirms Stonegate Capital Partners’ coverage of AB Science’s stock, which adds to the financial analyst consensus alongside Maxim Group, Chardan, In Extenso Finance and DNA Finance. 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 is key in signalling pathways within cells. Our programs target only diseases with high unmet medical needs, which are often lethal with short-term survival or rare or refractory to previous lines 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 being developed for human medicine. The company is headquartered in Paris, France and is 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, 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 uncertainties related to the 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 the 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 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_Stonegate_Update_1Q26_VENG_VF

MADRID, SPAIN and CAMBRIDGE, MA, UNITED STATES, June 2nd, 2026 - Oryzon Genomics, S.A. (ISIN Code: ES0167733015, Ticker: ORY), a clinical-stage biopharmaceutical company and a global leader in epigenetics, today announced that the first patient has been enrolled in IDEAL, its Phase II study evaluating iadademstat in patients with essential thrombocythemia (ET). IDEAL (IaDademstat treatment for EssentiAL thrombocythemia) is a multicenter, single-arm Phase II study being conducted in Spain in adult patients with ET who are resistant or intolerant to hydroxyurea. The study is designed to evaluate the safety, tolerability and clinical activity of iadademstat, including its efficacy in reducing the percentage of adult ET patients with abnormal platelet counts. Iadademstat will be administered for up to 24 weeks, with an additional 24-week extension period available for those benefiting from treatment. Dr. Carlos Buesa, Oryzon’s Chief Executive Officer, said, “The enrollment of the first patient in IDEAL represents another important milestone in the continued expansion of the iadademstat franchise. Over the last couple of years, we have significantly broadened the clinical development of iadademstat across hematologic malignancies, solid tumors and non-malignant hematology, generating a growing number of clinical catalysts across multiple disease settings. We believe essential thrombocythemia represents an attractive opportunity to explore the therapeutic potential of LSD1 inhibition in a chronic myeloproliferative disease where additional treatment options are needed.” “This milestone also comes at a particularly exciting time for the iadademstat program, as updated results from the ALICE-2 study in first line acute myeloid leukemia (AML) will be presented at EHA next week,” Dr. Buesa added. “The data reported to date have shown very encouraging efficacy, with 100% of responses and high complete remission rates, and we look forward to next week’s presentation with a larger patient cohort. We believe ALICE-2 continues to support the potential of iadademstat as a differentiated component of frontline AML treatment and highlights the progress being made across our hematology development portfolio.” Dr. Ana Limón, Oryzon’s Senior Vice-President of Clinical Development and Global Medical Affairs, added: “IDEAL will allow us to assess not only the clinical effects of iadademstat on platelet counts and hematologic responses, but also to further characterize the biological impact of LSD1 inhibition in this disease. We believe the study may provide important insights into the potential role of iadademstat across the broader spectrum of myeloproliferative disorders.” Essential thrombocythemia is the most common myeloproliferative neoplasm and is characterized by persistently elevated platelet counts and an increased risk of thrombotic complications. Despite available therapies, a significant proportion of patients become resistant or intolerant to first-line treatments such as hydroxyurea, highlighting the need for novel treatment options. Preclinical and clinical data support the role of LSD1 inhibition in regulating megakaryocyte maturation and platelet production, providing a scientific rationale for the evaluation of iadademstat in ET. Beyond ET, iadademstat continues to advance across a broad clinical development program in hematologic malignancies, solid tumors and non-malignant hematology. Updated data from the ongoing ALICE-2 study accepted for presentation at EHA 2026 showed a 100% overall response rate (ORR), 93% composite complete remission (CRc) rate, and 79% true complete remission (CR) rate at the abstract submission cut-off in first-line AML patients treated with the triplet combination of iadademstat, azacitidine and venetoclax. In addition, updated data from the FRIDA study evaluating iadademstat in combination with gilteritinib in relapsed/refractory FLT3-mutated AML demonstrated a favorable safety profile and a CRc rate of 67% in a heavily pre-treated patient population. Updated clinical results from both studies will be presented at the EHA 2026 Congress next week. Oryzon is also advancing the RESTORE trial evaluating iadademstat in sickle cell disease, and additional trials are in progress conducted under the Cooperative Research and Development Agreement (CRADA) with the U.S. National Cancer Institute (NCI) and as investigator-sponsored studies in myeloproliferative neoplasms, myelodysplastic syndrome and small cell lung cancer.