The Burden of Systemic Mastocytosis on Patients and Clinicians

Mariana C. Castells MD, PhD, Division of Allergy and Clinical Immunology, Brigham and Women's Hospital, and Professor of Medicine, Harvard Medical School, discusses the results of TouchStone, a patient and healthcare provider (HCP) survey focused on systemic mastocytosis.
Mastocytosis is a rare, hematologic disorder most often caused by a mutation in the KIT D816V gene. The disorder is characterized by uncontrolled mast cell proliferation and activation across multiple organ systems, resulting in chronic, severe, and often unpredictable symptoms and extensive organ damage.

There are a number of subtypes of mastocytosis including cutaneous mastocytosis and systemic mastocytosis. Cutaneous mastocytosis primarily affects children and the skin is the only site of involvement. In systemic mastocytosis, pathologic accumulation of mast cells is evident in tissue(s) other than skin – most commonly in bone marrow. Indolent systemic mastocytosis is generally associated with low mast cell burden and presence of mediator-related symptoms. Most patients with indolent systemic mastocytosis also have maculopapular skin lesions. Some patients may present with an enlarged liver or spleen and the gastrointestinal tract may also be affected. Life expectancy in patients with indolent systemic mastocytosis is comparable to the general population.

As Dr. Castells explains, the TouchStone study was designed to characterize the burden and needs of patients living with systemic mastocytosis. TouchStone was a collaborative research project led by Blueprint Medicines with the help of The Mast Cell Disease Society and Cancer Support Community. Recently, the results of this study were published in two papers titled "Patient-reported Outcomes Among Patients with Systemic Mastocytosis in Routine Clinical Practice: Results of the TouchStone SM Patient Survey" and "Perceptions of Patient Disease Burden and Management Approaches in Systemic Mastocytosis: Results of the TouchStone Healthcare Provider Survey.”

The TouchStone patient results were identified through a survey that enrolled 56 patients with self-reported systemic mastocytosis recruited from Blueprint Medicines' Mast Cell Connect Registry (NCT02620254). The patients completed 100 online questions, including valid patient-reported outcomes tools – the Indolent Systemic Mastocytosis Symptom Assessment Form (ISM-SAF), Short Form-12 (SF-12) and Work Productivity and Activity Impairment (WPAI) questionnaire – to characterize symptom burden, impact on daily living, emotional well-being, and quality of life. The results demonstrated that nearly two-thirds of patients reported avoiding leaving their home due to systemic mastocytosis symptoms and 66% experienced pain from symptoms that interfered with their ability to work, with 30% filing for medical disability due to their disease. More than 50% of patients reported taking 3 or more over-the-counter medications plus 3 or more prescription medications to manage the symptoms of their disease. 30% of patients reported seeking emergency care for anaphylaxis over the course of a year. Almost half (45%) of patients surveyed reported 3 or more annual visits to allergy/immunology specialists, while close to one-third of patients (31%) reported 3 or more visits to Hematology/Oncology.

The TouchStone HCP results were identified through an online 51-question survey administered to 111 U.S. physicians specializing in allergy/immunology or hematology/oncology who care for patients with systemic mastocytosis to characterize their perception of disease burden, patient needs and satisfaction with current management strategies in systemic mastocytosis. Surveyed HCPs reported that nearly 60% of their patients diagnosed with non-advanced systemic mastocytosis experienced moderate to severe symptoms and that they aggressively treated an average of 52% of their non-advanced systemic mastocytosis patients with symptom-directed prescription medications. More than 50% of HCPs noted that their patients with non-advanced systemic mastocytosis experience limitations across all aspects of their daily life, including school, work, sports, physical activity, sleep, leisure time, relationships and ability to care for their children. 41% of HCPs rated improving quality of life as the most important treatment goal for patients with non-advanced systemic mastocytosis, with symptom improvement the second most important treatment goal. For patients with advanced systemic mastocytosis, the primary treatment goal for more than 50% of HCPs surveyed was to reduce the risk of organ damage and improve progression-free survival or overall survival.
To learn more about systemic mastocytosis and other rare hematologic disorders, visit checkrare.com/diseases/hematologic-disorders/

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