AB Science Advances Masitinib ALS Phase 3 Trial as AB8939 Emerges as Second Pipeline Pillar

With a FDA-authorized confirmatory Phase 3 trial underway and an AML combination programme clearing Stage 3, AB Science's pipeline structure carries direct implications for regulatory affairs teams tracking NDA readiness timelines and manufacturing scale-up decisions. Stonegate Capital Partners updated its coverage of the company on 26 May 2026, following AB Science's full-year 2025 results, assigning a discounted cash flow valuation mid-point of €4.25 per share (range: €3.20 to €5.77).

Masitinib in ALS remains the lead asset. The confirmatory study, AB23005, is a 408-patient, 48-week trial evaluating masitinib 4.5 mg/kg/day plus riluzole versus placebo plus riluzole in normally progressing ALS patients without complete loss of function. Reported efficacy data from the target population include a 4.04-point ALSFRS-R benefit, a +20.2% relative CAFS benefit, a nine-month median progression-free survival benefit, and a 12-month median overall survival benefit. A potential plasma biomarker linked to microglia and mast-cell activity has also been identified, which could carry weight in future NDA submission strategy and patient stratification protocols.

AB8939 in acute myeloid leukemia is consolidating as a second clinical pillar. The AML combination programme has completed Stage 3, covering 14 days of AB8939 plus venetoclax, with Stage 4 planned to incorporate azacitidine subject to regulatory approval. Early data across four heavily pre-treated patients with difficult cytogenetics showed one complete remission, one near-complete response, and two partial responses. For QA and regulatory leads, the progression to a three-drug combination regimen will require close attention to comparability and process validation requirements as the programme advances.

Progressive multiple sclerosis and Alzheimer's disease remain in the pipeline but have been repositioned as partnership-led opportunities, reflecting the commercial infrastructure those indications demand. The capital allocation shift toward ALS and AML sharpens the near-term regulatory and operational focus for the organisation.

On the financial side, AB Science closed FY2025 with €10.2M in cash, supplemented by a €3.2M private placement in April 2026. Operating loss excluding non-recurring items declined 38% to €3.8M. Notably, the company received a clinical trial financial insurance offer for AB23005 providing excess-free coverage of €25M, extendable to €39M, intended to cover clinical-failure costs and offer third-party validation of the Phase 3 design, subject to study funding and premium payment. Stonegate notes that successful regulatory and operational de-risking could reduce the applied discount rate to approximately 15%, implying a valuation mid-point near €8.50 per share.

The AB23005 trial's interim data readout and the regulatory decision on Stage 4 azacitidine incorporation will serve as the next measurable checkpoints for teams monitoring masitinib's NDA pathway and AB8939's combination programme progression.

Source: AB Science via GlobeNewswire, 2 June 2026.