Riluzole

France-based AB Science SA (Euronext: AB) is narrowing its clinical focus to two programs — AB8939 in relapsed/refractory acute myeloid leukemia and masitinib in amyotrophic lateral sclerosis — while formally discontinuing three studies that had already suspended enrollment. The move signals a resource allocation decision by a small-cap company operating in two highly competitive indications. The three discontinued studies — a Phase II of masitinib in mast cell activation syndrome (AB20006), a Phase III in mastocytosis (AB15003), and a Phase III in progressive multiple sclerosis (AB20009) — were already dormant. AB Science stated the closures are not safety-related, framing them instead as a regulatory compliance measure for suspended trials with no prospect of near-term resumption. The discontinuations remove pipeline optionality but do not change the company’s near-term clinical trajectory. The more substantive update concerns AB8939, a microtubule-destabilizing agent designed to bypass two key resistance mechanisms in AML — P-glycoprotein-mediated drug efflux and myeloperoxidase-mediated drug inactivation. AB Science reported in late June the completion of Phase I, Step 3 — the maximum tolerated dose evaluation of AB8939 combined with AbbVie and Roche’s Venclexta (venetoclax) — and said the study’s Independent Data Monitoring Committee issued a preliminary favorable opinion. The company is now seeking regulatory authorization to initiate Phase I, Step 4, which will evaluate a triple combination of AB8939, venetoclax, and azacitidine. No numerical efficacy or safety data were disclosed. The R/R AML landscape has shifted substantially in recent years. Syndax Pharmaceuticals’ Revuforj (revumenib) received two separate US FDA approvals in 2024 and 2025 for KMT2A-translocated and NPM1-mutant AML, respectively, while Kura Oncology and Kyowa Kirin’s Komzifti (ziftomenib) gained approval for NPM1-mutant R/R AML in November 2025. These menin inhibitors are mutation-specific, which leaves a meaningful gap for mutation-agnostic approaches in patients who lack targetable alterations — the population AB8939 is theoretically positioned to address. Whether those preclinical findings translate into clinical benefit remains to be demonstrated. The masitinib ALS program presents its own complications. The Phase III trial AB23005, a 408-patient double-blind study comparing masitinib at 4.5 mg/kg/day plus riluzole against riluzole plus placebo, received regulatory approval in 2025 but has not yet enrolled a single patient. AB Science now says it will amend the protocol and resubmit before resuming the study. AB Science did not disclose the planned protocol amendments or the reasons for them. Masitinib previously generated Phase II/III data suggesting a slowing of disease progression in a subset of ALS patients, and AB Science submitted a marketing authorization application to the European Medicines Agency based on that dataset — an application that has not resulted in approval. The need to amend the confirmatory Phase III before it begins adds further delay to an already protracted regulatory path in a disease where riluzole and FDA’s Radicava (edaravone) remain the principal approved options. The pipeline update leaves AB Science focused on two lead programs at markedly different stages of development. For AB8939, the company is preparing to expand evaluation into a triple-combination regimen following the IDMC’s favorable opinion. For masitinib in ALS, the planned protocol amendment introduces additional uncertainty around the timeline for initiating the confirmatory Phase III study. This article was generated with AI assistance and reviewed and edited by the AllSci editorial team Explore more at AllSci News: https://allsci.com/news/ Your email address will not be published. Required fields are marked * Comment * Name * Email * Website Privacy Terms About Us Copyright © 2026. AllSci Corp. All rights reserved.

PRESS RELEASE AB SCIENCE PROVIDES AN UPDATE ON ITS CLINICAL PROGRAM, SUSPENDING SOME NON-PRIORITY CLINICAL TRIALS TO FOCUS ON TWO CLINICAL PROGRAMS Paris, July 10, 2026, 6pm CET AB Science SA (Euronext - FR0010557264 - AB) today provides an update on its clinical development program and announces the discontinuation of certain non-priority clinical studies in order to focus on two clinical programs, the AB8939 program for acute myeloid leukemia and the masitinib program for amyotrophic lateral sclerosis. Following the company’s press release dated April 16 [1], three clinical studies—which the company currently considers non-priority and for which patient enrollment had been suspended—are being discontinued, namely: Phase 2 study (AB20006) of masitinib in mast cell activation syndrome Phase 3 study (AB15003) of masitinib in mastocytosis Phase 3 study (AB20009) of masitinib in progressive forms of multiple sclerosis The discontinuation of these studies is not related to any safety concerns regarding masitinib. The company intends to complete these clinical studies in accordance with applicable regulations. Stéphane Ledermann, Chairman and CEO of AB Science, stated, “This decision to terminate non-priority studies for which recruitment had been suspended and for which there is no prospect of a rapid resumption reflects compliance with regulatory requirements. It is also consistent with our commitment to allocate all necessary resources to ensure the two priority programs are carried out to the highest standards of quality .” Regarding the AB8939 program for acute myeloid leukemia, the company announced [2] the completion of Phase 1, Step 3, evaluating the combination of AB8939 and venetoclax. The next step is to seek authorization from health authorities—based on a preliminary favorable opinion from the study’s Independent Data Monitoring Committee (IDMC)—to initiate Phase 4 of the study, which will evaluate the triple combination of AB8939, venetoclax, and azacitidine. Regarding the Phase 3 program for masitinib in amyotrophic lateral sclerosis, which was approved in 2025 [3] but has not yet begun, the company will update the protocol and its implementation procedures, and will seek authorization from health authorities to resume this study after submitting a substantial amendment. [1] Press release dated April 16, 2026 [2] Press release dated June 29, 2026 [3] Press release dated July 24, 2025 About AB23005 in ALS The AB23005 study is a prospective, multicenter, randomized, double-blind, placebo-controlled, two-arm study conducted in patients with amyotrophic lateral sclerosis (ALS), designed to confirm the efficacy and safety of masitinib (at a dose of 4.5 mg/kg/day in combination with riluzole) compared to riluzole plus placebo after 48 weeks of treatment. The study will include 408 patients (randomized in a 1:1 ratio) with ALS who are experiencing normal disease progression (i.e., a functional decline of less than 1.1 points per month) and who have not experienced a complete loss of function (i.e., a score of at least 1 on each of the 12 items of the ALSFRS-R scale). U.S. patients receiving edaravone will also be eligible to participate in the study, as the use of this medication constitutes a stratification factor. About AB18001 in AML The AB18001 study, titled “A Phase 1/2 Study to Evaluate the Safety, Pharmacokinetics, and Efficacy of AB8939 Administered Intravenously Daily in Patients with Relapsed/Refractory Acute Myeloid Leukemia , ” is designed in several phases. The first part is a dose-escalation study designed to assess the safety and tolerability of AB8939 and to determine the recommended dose for the Phase 2 expansion study. The objective of the Phase 1 study is to determine the maximum tolerated dose (MTD) for the different treatment regimens with AB8939. Phase 1: Determination of the MTD after 3 consecutive days of treatment with AB8939 alone. Phase 2: Determination of the MTD after 14 consecutive days of treatment with AB8939 alone. Phase 3: Determination of the MTD after 14 consecutive days of treatment with AB8939 in combination with venetoclax. Phase 4: Determination of the maximum tolerated dose (MTD) after 14 consecutive days of treatment with AB8939 in combination with venetoclax and azacitidine. 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 that play a critical role in cellular signaling. Our programs target only diseases with high unmet medical needs—often fatal conditions with low survival rates, rare diseases, or those resistant to first-line treatment. AB Science has independently developed a portfolio of molecules, and its lead compound, masitinib, has already been approved for veterinary use and is currently undergoing clinical development in humans. The Company is headquartered in Paris and is listed on Euronext Paris (Ticker: AB). For more information about the Company, visit the website: Forward-Looking Statements – AB Science This press release contains forward-looking statements. These statements are not historical facts. They include projections and estimates, as well as the assumptions on which they are based, and statements regarding plans, objectives, intentions, and expectations concerning future financial results, events, operations, services, product development and 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 by other similar terms. Although AB Science believes that these forward-looking statements are reasonable, investors are cautioned that such statements are subject to numerous risks and uncertainties—which are difficult to predict and generally beyond AB Science’s control—that may cause actual results and events to differ materially from those expressed, implied, or projected in the forward-looking information and statements. These risks and uncertainties include, in particular, uncertainties inherent in the development of the Company’s products—which may not be successful—or in the granting of marketing authorizations by the competent authorities, or, more generally, any factors that may affect the ability to commercialize the products developed by AB Science, as well as those developed or identified in public documents published by AB Science. AB Science makes no commitment to update forward-looking information and statements, subject to applicable regulations, in particular Articles 223-1 et seq. of the AMF’s General Regulations. For further information, please contact: AB Science Financial Communications investors@ab-science.com Attachment Clinical Program Update July 2026 VENG VF