Masitinib in Patients With Mastocytosis With Handicap and Bearing the D816V Mutation

Inclusion Criteria: 1. Patients with one of the following documented mastocytosis: * Smouldering systemic mastocytosis * Indolent systemic mastocytosis with organomegaly * Indolent Systemic Mastocytosis having 2 infiltrated organs (skin and bone-marrow) * Any mastocytosis with in the last 6 months at least 3 anaphylactic shocks or syncops requiring either use of adrenaline or medical assistance * Cutaneous Mastocytosis (CM) 2. Skin biopsy-documented mastocytosis and evaluable disease based upon: * Histological criteria: typical infiltrates of mast cells in a multifocal or diffuse pattern in skin biopsy * Clinical criteria: typical skin lesions (maculopapular, urticaria pigmentosa, mastocytoma) 3. Missing data (c-kit molecular analysis not done) or documented presence of an activating point mutation in the phosphotransferase domain of c-kit such as D816V c-kit mutation in at least one infiltrated organ (bone marrow or skin) 4. Refractory to at least one of the symptomatic treatments such as: * Anti H1 * Anti H2 * Proton pump inhibitor * Osteoclast inhibitor * Cromoglycate Sodium * Antileukotriene * Other therapies used for the symptomatic care 5. Handicap defined as at least one of the following handicaps: * pruritus score ≥ 6 * number of flushes per week ≥ 7 * number of stools per day ≥ 4 , * number of mictions per day ≥ 8 , * QLQ-C30 score ≥ 60, * Hamilton score ≥ 10 Exclusion Criteria: 1. Patients with one of the following mastocytosis: * Systemic Mastocytosis with an Associated clonal Hematologic Non Mast cell lineage Disease (SM-AHNMD) * Mast cell leukemia (MCL) * Aggressive systemic mastocytosis (ASM) 2. Patient with a major surgery within 2 weeks prior to study entry 3. No vulnerable population will be included in this study * Life expectancy \< 6 months. * Patient is \< 5 years free of malignancy, except treated basal cell skin cancer or cervical carcinoma in situ. * Patient with grade III/IV cardiac problems as defined by the New York Heart Association Criteria. (i.e., congestive heart failure, myocardial infarction within 6 months of study) * Patient has a severe and/or uncontrolled medical disease. * Patient has a known diagnosis of human immunodeficiency virus (HIV) infection