Multicenter, double-blind, placebo-controlled trial comparing two different dosing schemes over a 24-week treatment period.~Dosing scheme #1: Oral masitinib treatment at 3 mg/kg/day for 4 weeks, then a switch to 4.5 mg/kg/day for the remainder of the treatment period, versus placebo with a matching titration scheme. Randomization 2: 1 (Masitinib MCAS: Placebo MCAS).~Dosing scheme #2: Oral masitinib treatment at 3 mg/kg/day for 4 weeks, then a switch to 4.5 mg/kg/day for 4 weeks, then a second switch to 6 mg/kg/day for the remainder of the treatment period versus placebo treatment with a matching titration scheme. Randomization 2: 1 (Masitinib MCAS: Placebo MCAS)
To evaluate the efficacy and safety of two dosing schemes of oral masitinib versus matching placebo in the treatment of patients suffering from severe MCAS with handicap unresponsive to optimal symptomatic treatment.