Background: Mastocytosis is characterized by the accumulation of abnormal mast cells in various organs. Data on the prevalence of mastocytosis are heterogeneous, with the condition’s prevalence estimated to be between 9.6 and 23.9 per 100,000 inhabitants. Patients may present signs and symptoms that can severely impact quality of life (QoL), but reported data are scarce. Thus, we performed a nationwide study to estimate the prevalence and to assess the management and burden of adults with mastocytosis in France according to physician assessments. Methods: We developed an online survey comprising 25 questions investigating various aspects of mastocytosis and asked 6,239 physicians to respond. Data concerning physician characteristics and the number of patients followed were used to estimate overall prevalence. To assess patients’ QoL, we focused on the presence of signs and symptoms and the patients’ burden specifically in those with either indolent systemic mastocytosis (ISM) or mastocytosis in the skin (MIS). Results: Between July 11, 2023, and September 1, 2023, 1,169 physicians (18.7%) completed the survey. These physicians managed 4,121 mastocytosis patients, corresponding to an estimated prevalence of mastocytosis of 8.5 per 100,000 in France. In the ISM/MIS population (representing 76% of mastocytosis patients), 53% presented moderate to severe symptoms (mainly skin, digestive and general symptoms). Overall, physicians indicated that there was substantial burden associated with these symptoms in almost all fields of QoL analyzed. Conclusions: Our results provide further evidence of the burden associated with mastocytosis and highlight the need to improve QoL in these patients.

Background: Limited information is available on the use of omalizumab (OMA) updosing since its introduction as a second-line therapy in chronic spontaneous urticaria (CSU) in 2014. Practical guidelines from health authorities are lacking, and the specific characteristics of patients requiring higher doses remain unknown. Our objectives were to characterize the patterns of OMA updosing (defined as changes in dose and/or injection intervals), to identify the predictive factors associated with updosing, and to improve CSU management. Methods: We conducted a prospective, multicentric, real-life, observational study, including patients diagnosed with CSU and starting OMA. The data were collected at 0, 3, 6 and 9 months. The primary endpoint was the frequency of OMA updosing at 3 months. The secondary endpoints included an analysis of updosed patients’ profile, and an assessment of OMA efficacy and safety. Results: We included 153 patients. Twenty percent of patients at M3 were updosed, and 27% in total during the 9-month follow-up. Practitioners mainly chose to increase the frequency of injections (66%). At baseline, the updosed patients were more likely, to have inducible urticaria (50% vs. 33%, p=0.046), more severe CSU (UCT 3 vs. 4, p<0.001; DLQI 14 vs. 11, p=0.040), a lower lymphocyte count (1894 vs. 2100, p=0.026) and IgE below 70 UI/mL (65% vs. 45%, p=0.039). The side effects of OMA were not more frequent after updosing. Conclusion: One in five patient underwent updosing within just three months. OMA updosing is frequent in particular in cases of severe disease, inducible urticaria and low IgE blood levels.

A document by Antoine Badaoui. Click on the document to view its contents.