PARIS, July 10, 2026
AB Science announced a major strategic update to its clinical development pipeline, confirming that it will discontinue several non-priority clinical studies and redirect resources toward its two highest-priority development programs: AB8939 for acute myeloid leukemia (AML) and masitinib for amyotrophic lateral sclerosis (ALS). The company stated that the decision follows an internal portfolio review intended to optimize resource allocation and accelerate the development of programs with the greatest clinical and regulatory potential. Importantly, AB Science emphasized that the discontinuation of selected trials is not related to any safety concerns regarding masitinib, but rather reflects a strategic decision to focus investment, operational capacity, and regulatory activities on programs expected to deliver the greatest value for patients with serious diseases that have significant unmet medical needs. The company also confirmed that all discontinued studies will be closed in accordance with applicable regulatory requirements while maintaining patient safety and study integrity.
Company Ends Three Non-Priority Clinical Studies While Maintaining Safety Commitment
As part of the updated development strategy, AB Science will discontinue three previously suspended clinical trials, including the Phase 2 AB20006 study evaluating masitinib in mast cell activation syndrome, the Phase 3 AB15003 trial in mastocytosis, and the Phase 3 AB20009 study in progressive forms of multiple sclerosis. The company explained that patient recruitment for these studies had already been suspended and there was no realistic prospect for restarting enrollment in the near future. Chairman and Chief Executive Officer Stéphane Ledermann stated that terminating these non-priority programs demonstrates compliance with regulatory obligations while allowing the company to dedicate financial and operational resources toward programs considered strategically essential. AB Science reiterated that the decision was not driven by adverse safety findings, reinforcing confidence in the established safety profile of masitinib while enabling the company to concentrate on clinical programs that are closer to important development milestones.
AB8939 AML Program Advances Toward Triple Combination Clinical Evaluation
The company’s AB8939 program for relapsed or refractory acute myeloid leukemia continues to make progress following the successful completion of Phase 1 Step 3, which evaluated AB8939 in combination with venetoclax. Based on a preliminary favorable recommendation from the Independent Data Monitoring Committee (IDMC), AB Science plans to seek regulatory authorization to initiate Phase 4, evaluating a triple-drug combination consisting of AB8939, venetoclax, and azacitidine. According to the company, the ongoing AB18001 Phase 1/2 clinical study is designed to evaluate the safety, pharmacokinetics, and efficacy of AB8939 through sequential dose-escalation stages before advancing into combination treatment strategies intended to improve outcomes for patients with relapsed or refractory AML. By progressing into triple-combination therapy, AB Science aims to further strengthen the clinical potential of its novel investigational treatment in one of the most challenging hematologic malignancies.
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Masitinib ALS Program Remains Central to Long-Term Development Strategy
Alongside its oncology program, AB Science reaffirmed that the Phase 3 masitinib program in amyotrophic lateral sclerosis (ALS) remains a top corporate priority. Although the study received regulatory approval in 2025, enrollment has not yet begun, and the company now plans to update the clinical protocol and implementation procedures before submitting a substantial amendment to health authorities seeking authorization to restart the study. The AB23005 Phase 3 trial is designed as a randomized, double-blind, placebo-controlled study involving approximately 408 ALS patients, evaluating masitinib in combination with riluzole over a 48-week treatment period. The trial will assess efficacy and safety in patients with normal disease progression while including eligible U.S. patients receiving edaravone as a predefined stratification factor. By concentrating its scientific expertise and financial resources on AB8939 for AML and masitinib for ALS, AB Science is positioning its pipeline around two advanced clinical programs addressing severe diseases with substantial unmet medical need, reinforcing its long-term strategy of developing targeted therapies capable of delivering meaningful therapeutic advances in oncology and neurology.
Source: AB Science press release
