Systemic mastocytosis, though a rare disease, is more common than clinicians may think and diagnosis of the condition can often be missed. In this insightful interview, Deepti Radia, MBBS, MRCPI, FRCPath, of Guy’s and St Thomas’ Hospital NHS Foundation Trust, London UK, details the latest updates in the field, such as the new WHO classification guidelines for diagnosis and classification. Dr Radia also discusses the treatment options for this condition, which often consists of symptomatic treatment, but in cases of aggressive systemic mastocytosis there are now targeted treatments available, such as midostaurin, BLU-285 and DCC-2618. This video was recorded at the Myeloproliferative Neoplasms Advances Day 2017, London, UK.

Brenton Mar, MD, PhD, Senior Medical Director at Blueprint Medicines, gives an overview of systemic mastocytosis (SM) and advanced SM.

SM 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. A minority of SM patients have advanced SM, which encompasses a group of high-risk SM subtypes including aggressive systemic mastocytosis (ASM), systemic mastocytosis with an associated hematological neoplasm (SM-AHN), and mast cell leukemia (MCL).
As Dr. Mar explains, the diagnostic journey for SM patients is often long, especially for those who do not have an advanced form of the disease for which diagnosis can take 7 years. Even in advanced SM, diagnosis can take up to 2 years. Since advanced SM is often life-threatening, non-diagnosis can be fatal.

SM-AHN is the most common form of advanced SM which means advanced SM patients often have another hematologic disorder. As Dr. Mar explains, this can lead to problems when trying to diagnose these patients because the symptoms of the associated hematologic neoplasm may mask the signs of SM.

Finally, Dr. Mar describes signs of SM that physicians can look out for. Urticaria pigmentosa is the most common symptom though severe weight loss and refractory ascites may also suggest SM. Additionally, with the advent of next-generation sequencing, a mutation in the KIT D816V gene may also indicate SM.

To learn more about SM and other rare hematologic disorders, visit checkrare.com/diseases/hematologic-disorders/

Brenton Mar, MD, PhD, Senior Medical Director at Blueprint Medicines, gives an overview of systemic mastocytosis and advanced systemic mastocytosis.

As Dr. Mar explains, systemic 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.

A minority of systemic mastocytosis patients have advanced systemic mastocytosis, which encompasses a group of high-risk subtypes including aggressive systemic mastocytosis, systemic mastocytosis with an associated hematological neoplasm, and mast cell leukemia.

There is currently no approved treatment for systemic mastocytosis; however, recently avapritinib was approved for the treatment of advanced systemic mastocytosis.

To learn more about systemic mastocytosis and other rare hematologic disorders, visit checkrare.com/diseases/hematologic-disorders/