CANCER Publishes Study Demonstrating Substantial Disease Burden for Patients with Systemic Mastocytosis

-- Patients across the spectrum of disease reported substantial symptom burden, as well as scores of physical functioning and mental health that are worse than historical data for patients with colorectal or lung cancer --

CAMBRIDGE, Mass., Aug. 24, 2022 /PRNewswire/ -- Blueprint Medicines Corporation (NASDAQ: BPMC) today announced two publications in the medical journal CANCER describing results from the TouchStone patient and healthcare provider (HCP) study designed to characterize the burden and needs of patients living with systemic mastocytosis (SM). Patient-reported results indicated that SM is associated with severe and burdensome symptoms including anaphylactic events, frequent emergency department visits, use of multiple symptom-directed medications, reduced ability to work, impaired physical functioning and poor quality of life. HCP results reinforced the significant disruption to daily living caused by SM, highlighting the need for new therapies that improve patient quality of life and reduce disease symptoms. TouchStone was a collaborative research project led by Blueprint Medicines and involving disease experts, The Mast Cell Disease Society and Cancer Support Community.

SM is a rare hematologic disorder driven by the KIT D816V mutation in nearly all cases. The vast majority (90-95 percent) of those affected have non-advanced (indolent or smoldering) SM, with debilitating symptoms that lead to a profound negative impact on quality of life. A minority of patients have advanced SM, which encompasses a group of high-risk SM subtypes including aggressive SM, SM with an associated hematological neoplasm, and mast cell leukemia. In addition to mast cell activation symptoms, advanced SM is associated with organ damage due to mast cell infiltration and poor survival.

"These new observational data published in CANCER meaningfully advance our understanding of the significant disease burden of systemic mastocytosis, with many patients experiencing persistent disability, poor quality of life and frequent rates of anaphylaxis," said Ruben Mesa, M.D., hematologist/oncologist, executive director of Mays Cancer Center at UT Health San Antonio and lead author of the CANCER publications. "These results reinforce the need for coordination across multiple specialists to address the medical challenges of SM, and the studies underscore the importance of elevating standards of care for all those impacted by the disease." 

"For patients with systemic mastocytosis, the TouchStone results bring to life the real-world impact of the debilitating disease symptoms characteristic of systemic mastocytosis. These include poor physical and mental health, reduced ability to work and perform activities of daily living, high healthcare utilization and extensive symptom-directed polypharmacy," said Becker Hewes, M.D., Chief Medical Officer at Blueprint Medicines. "We are proud to partner with renowned disease experts and deeply committed patient advocates to design and conduct this study and now to bring the results forward to the community as part of our goal to improve the lives of patients living with SM."

The TouchStone SM Patient results were identified through a survey that enrolled 56 patients with self-reported SM recruited from Blueprint Medicines' Mast Cell Connect Registry (NCT02620254). The patients completed 100 online questions, including valid patient-reported outcomes (PRO) 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, SM impact on daily living, emotional well-being and quality of life. Highlights from the patient results include:

• Nearly two-thirds of patients reported avoiding leaving their home due to SM symptoms and 66 percent experienced pain from symptoms that interfered with their ability to work, with 30 percent filing for medical disability due to their disease.
   
• More than 50 percent of patients reported taking three or more over-the-counter medications plus three or more prescription medications to manage the symptoms of their disease.
   
• 30 percent of patients reported seeking emergency care for anaphylaxis over the course of a year. Annual visits to specialists were particularly common. Almost half (45%) of patients surveyed reported three or more annual visits to Allergy/Immunology specialists, while close to one-third of patients (31%) reported three or more visits to Hematology/Oncology.

The TouchStone SM 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 SM to characterize their perception of disease burden, patient needs and satisfaction with current management strategies in SM. Highlights from the HCP results include:

• Surveyed HCPs reported that nearly 60 percent of their patients diagnosed with non-advanced SM experienced moderate to severe symptoms and that they aggressively treated an average of 52 percent of their non-advanced SM patients with symptom-directed prescription medications.
   
• More than 50 percent of HCPs noted that their patients with non-advanced SM 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 percent of HCPs rated improving quality of life as the most important treatment goal for patients with non-advanced SM, with improvement of symptoms the second most important treatment goal in this population. For patients with advanced SM, the primary treatment goal for more than 50 percent of HCPs surveyed was to reduce the risk of organ damage and improve progression-free survival or overall survival.

The 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," were published online in CANCER on August 23, 2022.

About Systemic Mastocytosis

Systemic mastocytosis (SM) is a rare disease primarily driven by the KIT D816V mutation. Uncontrolled proliferation and activation of mast cells result in chronic, severe and often unpredictable symptoms for patients across the spectrum of SM. The vast majority of those affected have non-advanced (indolent or smoldering) SM, with debilitating symptoms that lead to a profound, negative impact on quality of life. A minority of patients have advanced SM, which encompasses a group of high-risk SM subtypes including aggressive SM (ASM), SM with an associated hematological neoplasm (SM-AHN) and mast cell leukemia (MCL). In addition to mast cell activation symptoms, advanced SM is associated with organ damage due to mast cell infiltration and poor survival. Across advanced SM subtypes, the median overall survival is approximately 3.5 years in ASM, approximately two years in SM-AHN and less than six months in MCL.

Debilitating symptoms, including anaphylaxis, maculopapular rash, pruritis, diarrhea, brain fog, fatigue and bone pain, often persist across all forms of SM despite treatment with a number of symptom-directed therapies. Patients often live in fear of severe, unexpected symptoms, have limited ability to work or perform daily activities, and isolate themselves to protect against unpredictable triggers. Historically, there had been no approved therapies for the treatment of SM that selectively inhibit D816V mutant KIT.

About Blueprint Medicines

Blueprint Medicines is a global precision therapy company that invents life-changing therapies for people with cancer and blood disorders. Applying an approach that is both precise and agile, we create medicines that selectively target genetic drivers, with the goal of staying one step ahead across stages of disease. Since 2011, we have leveraged our research platform, including expertise in molecular targeting and world-class drug design capabilities, to rapidly and reproducibly translate science into a broad pipeline of precision therapies. Today, we are delivering approved medicines directly to patients in the United States and Europe, and we are globally advancing multiple programs for systemic mastocytosis, lung cancer and other genomically defined cancers, and cancer immunotherapy. For more information, visit www.BlueprintMedicines.com and follow us on Twitter (@BlueprintMeds) and LinkedIn.

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