Masitinib proves effective in reducing Severe Asthma Exacerbations

The study, "Masitinib Significantly Decreases the Rate of Asthma Exacerbations in Patients with Severe Asthma Uncontrolled by Oral Corticosteroids: A Phase 3 Multicenter Study," was presented at the ATS 2020 International Conference.

Masitinib is a first-in-class drug in severe asthma that selectively targets mast cells through inhibition of tyrosine kinases c-Kit, LYN, and FYN. Previous research has demonstrated the therapeutic potential of and rationale for targeting mast cells in asthma. However, the AB07015 trial was the first positive large-scale study in severe asthma utilizing a drug of this kind.

The AB07015 study, led by Pascal Chanez, MD, Ph.D., Professor of Respiratory Diseases, Aix-Marseille University, France was a randomized, double-blinded, placebo-controlled trial that evaluated the efficacy of 6 mg/kg/day of masitinib treatment for severe persistent asthma.

A total of 355 patients were included in the study. The researchers especially noted patients with an initial eosinophil count of ≥150 cells/μL, which the investigators considered a key subgroup for their analysis.

The investigators also assessed a safety population — which included 404 patients, all of whom received at least 1 dose of the investigative drug, which included low-dosage.

Following enrollment, patients were randomized 2:1 to receive either masitinib or placebo for 36 weeks, with a possible extension period until at least week 96. Baseline characteristics and average exposure times (60 weeks) were well-balanced across treatment arms, they noted.

The primary endpoint of the research was the reduction of annualized severe asthma exacerbation rate for overall exposure (including extension period), with a severe exacerbation event defined as worsening asthma leading to an increase from stable maintenance dose of corticosteroids for ≥3 days or hospitalization.

Following the treatment period, Chanez and team reported the following findings-

a. Masitinib significantly reduced the severe asthma exacerbation rate by 35% compared with the placebo.

b. The eosinophil ≥150 cells/μL subpopulation demonstrated a significant reduction in severe exacerbations by 38%.

c. 83.4% of masitinib users experienced ≥1 adverse event—compared with 82.0% in placebo users.

d. The rates for serious and severe adverse events for masitinib were 17.7% and 16.5%, respectively. For placebo, these rates were 48.0% and 45.9%, respectively.

Based on the outcomes, the authors concluded that "Masitinib, a first-in-class tyrosine kinase inhibitor targeting mast cell activity in severe asthma patients, demonstrated a positive benefit/risk ratio over a sustained period and may provide a new treatment option in severe asthma, irrespective of baseline eosinophil level."