
AB Science has announced positive data from the Phase II trial investigating lead asset masitinib in hospitalised Covid-19 patients, highlighting that it improved the clinical status of patients after 15 days of treatment in combination with investigational antiviral isoquercetin.
While the data backs the anti-inflammatory activity of masitinib, the company has not disclosed detailed development plans.
Oliver Hermine, president of the scientific committee of AB Science said: “With this result, masitinib can be considered a drug of choice to be evaluated in the context of a future pandemic.”
The study (NCT04622865) found that after 15 days, the odds ratio was 2:4 in favour of the treatment arm, surpassing the initially hypothesised 2.2, with a statistically significant p-value in a simulation with 200 patients. Sensitivity analyses at days 12, 13, and 14 with 95 patients showed stronger treatment effects and statistically significant p-values.
The trial originally aimed to enrol 200 patients to improve their clinical status after 15 days of treatment using the WHO seven-point ordinal scale. Following advice from a data and safety monitoring board, the study focused on hospitalised patients with moderate Covid-19, defined as needing less than six litres of oxygen per minute with SpO₂ more than 92%.
Due to recruitment challenges, the study stopped enrolling 95 patients. The goal was then to detect a trending treatment effect with these 95 patients that would translate into significant benefits if the full 200 participants were enrolled.

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By GlobalDataMasitinib is an orally administered tyrosine kinase inhibitor, which is being developed as a novel SARS-CoV-2 protease inhibitor antiviral therapy. It is also proposed to have a potential inhibitory action on mast cells, an important component of the inflammatory network.
Masitinib has been evaluated in clinical trials for a range of diseases, including cancers, multiple sclerosis (MS), and amyotrophic lateral sclerosis (AML).
This positive Covid-19 data comes just a month after the Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency (EMA) recommended against granting conditional marketing authorisation to masitinib as an add-on treatment for ALS. The negative opinion was due to several alleged issues with clinical practice and analysis data from the Phase I/III AB10015 trial that involved 394 adults with ALS (NCT02588677). AB Science announced that it will ask for a re-examination.
The drug was co-developed by AB Science and the University of Chicago (UC) after the latter discovered that masitinib hinders the main protease needed for the SARS-CoV-2 viral replication cycle.
Elsewhere in the Covid-19 treatment space, AstraZeneca’s Phase III SUPERNOVA trial of sipavibart (formerly AZD3152) met its primary endpoint in preventing Covid-19 among immunocompromised individuals, in May 2024.