PRESS RELEASE AB SCIENCE REPORTS FOURTH CONSECUTIVE CASE OF RESPONSE FROM PHASE 1 DATA FOR THE COMBINATION OF AB8939 WITH VENETOCLAX FOR THE TREATMENT OF REFRACTORY OR RELAPSED ACUTE MYELOID LEUKEMIA The combination treatment was well-tolerated, with no hematological toxicity and no dose limiting toxicity The fourth patient had a complex karyotype including a monosomy of chromosome 5 and TP53 mutation, and was in the third-line of treatment. He had a near complete response after 14 days of treatment with AB ...

Core Viewpoint - AB Science has published a new article identifying AB8939 as a promising drug candidate for treating refractory acute myeloid leukemia (AML) and potentially other cancers, highlighting its dual mechanism of action and effectiveness against multidrug resistance [1][2]. Group 1: Drug Candidate Characteristics - AB8939 is characterized as a novel synthetic microtubule destabilizer and ALDH inhibitor, showing potential for treating high-risk AML, particularly in cases with complex karyotypes, MECOM rearrangements, and TP53 mutations [3][4]. - The drug exhibits dual action against proliferating tumor cells through tubulin disruption and quiescent, resistant stem cells via ALDH inhibition, making it a unique therapeutic agent [3][4]. Group 2: Mechanism of Action - AB8939 acts as a microtubule-targeting agent by binding to the colchicine-binding site on β-tubulin, disrupting the microtubule network, leading to cell cycle arrest in the G2/M phase and subsequent apoptosis [4]. - It is a potent inhibitor of ALDH1 and ALDH2 enzymes, which are often overexpressed in tumors and associated with cancer stem cells, tumor progression, and resistance to therapy [4]. Group 3: Efficacy and Resistance - AB8939 demonstrates strong antiproliferative activity against various human cancer cell lines, particularly hematopoietic cancers, with IC₅₀ values in the nanomolar range [4]. - The drug can overcome major mechanisms of drug resistance, including P-glycoprotein (P-gp) efflux and high β3-tubulin expression, retaining efficacy in resistant AML patient blasts [4][5]. Group 4: Clinical Trials - AB8939 is currently being evaluated in a Phase I/II clinical trial (AB18001) for patients with refractory and relapsed AML, with regulatory approval received to initiate the third stage of the study [5][6]. - The first two stages of the trial involved 28 and 13 patients, respectively, determining the maximum tolerated dose (MTD) of 21.3 mg/m² after both three and fourteen consecutive days of treatment [6]. Group 5: Intellectual Property and Regulatory Status - AB8939 is protected by intellectual property rights until 2036 or even 2044, with a patent covering its composition and use in AML treatment granted in multiple countries [7][8][9]. - The drug has received orphan drug designation from both the European Medicines Agency (EMA) and the US Food and Drug Administration (FDA), granting it marketing exclusivity for 10 years in Europe and 7 years in the US [10].

PRESS RELEASE AB SCIENCE ANNOUNCES A NEW PUBLICATION ON BIORXIV THAT IDENTIFIES AND CHARACTERIZES A NOVEL SMALL SYNTHETIC MOLECULE, AB8939, AS A PROMISING DRUG CANDIDATE FOR TREATING REFRACTORY ACUTE MYELOID LEUKEMIA (AML) AND POTENTIALLY OTHER CANCERS AB8939 is a promising drug candidate for refractory AML, especially for cases with poor prognoses such as complex karyotypes, MECOM rearrangements, and TP53 mutations AB8939 has dual action against both proliferating tumor cells (via tubulin disruption) and q ...

Core Viewpoint - AB Science has successfully completed a private placement raising EUR 2.8 million to finance the clinical development of its drug candidate AB8939 for acute myeloid leukemia (AML) [2][4]. Use of Proceeds - The net proceeds from the private placement will primarily be used to complete phase 1 of the AB8939 program and to initiate an expansion study involving approximately 15 AML patients [4][5]. Financial Impact - The private placement strengthens the company's cash position, allowing it to meet its financing needs for 2025 and beyond [5]. Private Placement Details - The private placement involved the issuance of 2,477,877 new ordinary shares, each accompanied by a share warrant (BSA), without preferential subscription rights [6][7]. - The issue price of one ABSA is set at EUR 1.13, reflecting a 24.99% discount to the volume-weighted average price over the preceding three trading days [8][9]. Shareholding Structure - Post-private placement, the company's total share capital will amount to EUR 729,474.72, consisting of 66,184,793 ordinary shares, with potential dilution from the exercise of BSAs [13][15]. Trading Information - The new shares are expected to be admitted to trading on Euronext Paris on October 22, 2025, and will be assimilated to existing shares [18]. Company Overview - AB Science specializes in the research, development, and commercialization of protein kinase inhibitors, targeting diseases with high unmet medical needs [25]. - The lead compound, masitinib, is already registered for veterinary use and is being developed for human medicine across various disease areas [25]. Drug Candidate Information - AB8939 is a synthetic microtubule-destabilizing drug candidate with broad anticancer activity, showing potential to overcome drug resistance commonly seen in chemotherapy [24].

Core Points - The web conference organized by AB Science aims to provide an update on the clinical development of their lead drug, AB8939 [1][3] - The presentation will be technical in nature, focusing on the progress of AB8939, which is currently in Phase I of clinical trials [3] Group 1 - Alain Moussy serves as the Co-Founder, Chairman, President, CEO, MD, and Scientific Director of AB Science [1] - The conference features notable experts including Nicholas Short, Olivier Hermine, and Christian Auclair, who contribute to the scientific and clinical aspects of the drug development [2] - Laurent Guy, the Chief Financial Officer, will address questions from participants at the end of the presentation [2]

Core Insights - AB Science SA has provided initial Phase 1 data for the combination of AB8939 with Venetoclax for treating refractory or relapsed acute myeloid leukemia (AML) [1] Group 1: Clinical Data and Efficacy - Early data indicates that AB8939, either as monotherapy or in combination, shows significant activity in high-risk subtypes of AML [2] - The combination of AB8939 and Venetoclax has demonstrated a disease control rate of 100% (3/3) and a partial response rate of 100% (3/3), including one patient achieving complete remission after the first treatment cycle [5][9] - AB8939 has shown activity in MECOM, with long overall survival benefits, and is effective in cell lines resistant to standard treatments [10][8] Group 2: Mechanism of Action - AB8939 operates through a dual mechanism: disrupting microtubules to block leukemia cell proliferation and targeting leukemia stem cells by inhibiting ALDH [10][11] - The combination with Venetoclax is expected to enhance apoptosis in cancer cells, as AB8939 destabilizes microtubules while Venetoclax inhibits the BCL2 pathway, which is crucial for AML resistance [11] Group 3: Market Potential - The addressable market for AB8939 in relapsed/refractory AML is estimated to exceed EUR 2 billion annually [13] - The total incidence of AML cases is approximately 90,200 globally, with significant relapse rates, indicating a persistent unmet medical need [14] Group 4: Next Steps and Development Plans - The next steps include completing Phase 1 in combination therapy and launching an expansion study involving around 15 AML patients eligible for AB8939 + Venetoclax [12] - Discussions with regulatory bodies such as the FDA and EMA are ongoing regarding potential registrational studies for AB8939 [13] Group 5: Intellectual Property - AB8939's intellectual property rights in AML are secured until 2036, with potential extensions until 2044 for specific genetic abnormalities [18]

Core Insights - AB Science has released initial data on the combination of AB8939 and Venetoclax for treating refractory or relapsed acute myeloid leukemia (AML), showing positive responses in the first three patients with unfavorable genetic profiles [1][2][5] Group 1: Clinical Trial Details - AB8939 is currently in a Phase 1 clinical trial (study AB18001, NCT05211570) targeting refractory and relapsed AML [3][4] - The trial has completed its first two stages, determining the maximum tolerated dose (MTD) at 21.3 mg/m² after 3 and 14 days of monotherapy [4] - The third stage is evaluating the combination of AB8939 and Venetoclax, with initial results showing a 100% disease control rate and a 100% partial response rate among the three patients [5][6] Group 2: Patient Profiles and Responses - The three patients involved in the trial have very difficult-to-treat cytogenetic profiles, including TP53 mutations and complex karyotypes, which are typically associated with poor prognosis [5][6] - Notably, one patient achieved complete remission after the first cycle of treatment, which lasted 14 days [5][6] Group 3: Future Directions - Following the initial encouraging results, the trial will continue with an expansion phase involving about 15 patients with a more homogeneous profile, specifically targeting those in their second or third line of treatment with poor prognostic factors [6] - The ongoing research aims to confirm the initial promising clinical data before initiating a registration clinical trial [6] Group 4: Company Background - AB Science is a pharmaceutical company founded in 2001, specializing in the research, development, and commercialization of protein kinase inhibitors (PKIs) [12][13] - The company focuses on diseases with high unmet medical needs, often lethal or rare, and has developed a proprietary portfolio of molecules [12][13]

Financial and Corporate Situation - AB Science reported a reduced operating deficit of €2.7 million for the first half of 2025, a decrease of 24% compared to €3.6 million in the same period of 2024 [4][3] - The company raised €6.3 million through private placements to support ongoing activities, particularly the clinical development of the AB8939 program [25] - The net loss for the first half of 2025 was €5.2 million, an increase of 15.8% from a loss of €4.5 million in the first half of 2024 [6][7] Clinical Development - AB Science received authorization from several European countries for a Phase 3 confirmatory study with masitinib in amyotrophic lateral sclerosis (ALS) [8] - The FDA and EMA approved a Phase 3 confirmatory study with masitinib in metastatic hormone-resistant prostate cancer [13] - New data indicated the efficacy of masitinib in treating Alzheimer's disease, showing improvements in cognitive and behavioral symptoms in a mouse model [15][16] - The AB8939 molecule received orphan drug designation from the EMA for the treatment of acute myeloid leukemia (AML) [21] - A Canadian patent was granted for AB8939, providing protection until 2036 [23] Financial Results Summary - Operating income was €515 thousand, down from €560 thousand in the first half of 2024, attributed to a temporary decline in sales of veterinary medicine [5][7] - Operating expenses decreased by 21.7%, with administrative expenses down by 31.1% [5] - Financial income for the first half of 2025 was €212 thousand, while financial expenses amounted to €2.7 million [7]

Core Points - AB Science S.A. successfully completed a private placement raising a total gross amount of EUR 2.55 million from a limited number of investors [1][3][4] Use of Proceeds - The net proceeds from the private placement will be used to finance ongoing activities, particularly focusing on the clinical development of the AB8939 program [3] Private Placement Details - The private placement involved the issuance of 2,276,787 new ordinary shares, each with one share warrant attached, without preferential subscription rights [4][5] - The issue price of one ABSA is EUR 1.12, representing a 24.68% discount to the volume-weighted average price over the three trading days preceding the price setting [6][7] Share Capital Impact - Following the issuance, the company's total share capital will be EUR 704,695.95, consisting of 63,706,916 ordinary shares, which could increase to 65,983,703 shares if all warrants are exercised [11][12] Trading and Admission - The new shares are expected to be admitted to trading on Euronext Paris on August 7, 2025, and will be assimilated to existing shares [15] About AB Science - AB Science specializes in the research, development, and commercialization of protein kinase inhibitors, targeting diseases with high unmet medical needs [24]

Core Viewpoint - AB Science has received regulatory approval from several European countries to initiate the third stage of its Phase I/II study combining AB8939 with venetoclax for treating acute myeloid leukemia (AML), indicating potential advancements in treatment options for patients with relapsed/refractory AML [1][4]. Group 1: Study Details - The third stage of the study has been approved in France, Germany, Spain, and Greece, focusing on determining the maximum tolerated dose (MTD) of AB8939 [2]. - The first two stages of the Phase I study involved 28 and 13 patients, respectively, establishing the MTD of AB8939 at 21.3 mg/m² after both 3 and 14 consecutive days of treatment [3]. - The current stage will evaluate the MTD after 14 consecutive days of treatment with AB8939 in combination with venetoclax, a standard treatment for AML [3][6]. Group 2: Treatment Rationale - The combination of AB8939 and venetoclax is expected to have low hematologic toxicity, potentially making it less toxic than the current standard treatment of azacitidine plus venetoclax [5]. - Both compounds target different mechanisms in cancer cells, which may lead to additive or synergistic effects in efficacy [5][9]. - AB8939 destabilizes microtubules, preventing cancer cell division, while venetoclax inhibits BCL2, promoting apoptosis in cancer cells, thus addressing resistance mechanisms [7][13]. Group 3: Market Potential - The estimated market potential for AML treatments exceeds €2 billion annually, with significant addressable markets in the United States, Europe, and Asia-Pacific [11][12]. - The total incidence of AML in the United States, Europe, and Asia-Pacific is approximately 79,100 cases, with a significant portion being poor responders to standard therapies [12][15]. Group 4: Intellectual Property and Regulatory Status - AB8939 is protected by patents until 2026, with potential extensions and additional protections for specific uses in AML, extending to 2044 for certain chromosomal abnormalities [16][18]. - The drug has received orphan drug designation from both the EMA and FDA, granting it marketing exclusivity for 10 years in Europe and 7 years in the US [19].