AB Science SA announced that results from the pivotal phase 3 (AB06006) study of masitinib in severe indolent systemic mastocytosis were published in The Lancet, following peer review. Masitinib is the first drug to demonstrate efficacy in a phase 3 study of adult patients with severe indolent systemic mastocytosis, including the subvariant of smouldering systemic mastocytosis, who are unresponsive to existing, optimal symptomatic treatments. Below is the summary of the article published in The Lancet: In this pivotal phase 3 study (AB06006), masitinib administered at 6 mg/kg/day was significantly superior to placebo, as measured by the cumulative 75% response rate until week 24 on the handicaps of pruritus or flushes or depression or fatigue (primary endpoint 4R75%). The 4R75% response was 18.7% for the masitinib treatment-arm versus 7.4% for the placebo treatment-arm (p=0.0076). Subgroup analysis in patients with the KIT Asp816Val (D816V) mutation (90% of the population) also showed a significant response in favour of masitinib, with a 4R75% response of 20.2% for masitinib versus 7.4% for placebo (p=0.0316). Treatment response was sustained over a period of 2 years. Safety assessment showed a comparable incidence of adverse events between treatment-arms. Masitinib is the first drug to show significant therapeutic benefit across a diverse range of symptoms as well as objective markers of mast cell activation in patients with severe indolent systemic mastocytosis. Based on the phase 3 study results, the company filed for registration to the European Medicines Agency (EMA) in April 2016 for masitinib in severe indolent systemic mastocytosis.