I am KIT D816V. I am the genomic mutation that is the central driver of systemic mastocytosis (SM). See how I cause uncontrolled proliferation and activation of mast cells, resulting in an array of severe and unpredictable symptoms in your patients.1,7,13

Know the underlying cause of systemic mastocytosis

The KIT D816V mutation is the central driver of systemic mastocytosis in ~95% of cases.1

Other less common somatic KIT mutations identified in adult systemic mastocytosis include V560G, D815K, D816Y, insVI815-816, D816F, D816H, and D820G.1 Patients with no KIT mutation detected have been described as well in rare cases.14

See how KIT D816V plays a central role in SM

As per the World Health Organization (WHO) guidelines, systemic mastocytosis is a myeloid neoplasm classified into 5 subtypes.10,15,16

Myeloid neoplasms
Myeloproliferative neoplasm (MPN)
Myeloid/lymphoid neoplasms with eosinophilia
Myelodysplastic syndrome/ myeloproliferative neoplasm (MDS/MPN)
Myelodysplastic syndrome
Myeloid neoplasm with germline predisposition

KIT D816V: The root cause of a broad range of potential clinical consequences1,3,7

The KIT D816V mutation causes the receptor tyrosine kinase to be constitutively active, leading to the uncontrolled proliferation and activation of abnormal mast cells. This occurs across multiple organ systems, including the bone marrow, liver, spleen, skin, and other organs.3,17,18


Activated mast cells release powerful mediators, including:

  •  Cytokine-chemokines
  •  Endothelin
  •  Histamine
  • Nitric oxide
  •  PAF/lipid mediators
  • Tryptase


  • Anaphylaxis with hypotension and syncope
  • Dizziness
  • Palpitations


  • Darier's sign
  • Dermatographism
  • Extreme flushing
  • Pruritus


  • Abdominal pain or cramping
  • Diarrhea
  • Heartburn or reflux
  • Nausea and/or vomiting


  • Anxiety
  • Brain fog
  • Depression
  • Lack of focus/memory
  • Memory loss
  • Migraines


  • Dyspnea
  • Nasal congestion
  • Throat swelling
  • Wheezing


  • Bone pain
  • Muscle pain
  • Osteoporosis/ osteopenia


  • Anaphylaxis
  • Fatigue
  • Malaise
  • Weight loss

Organopathy due to mast cell infiltration can also occur, causing lymphadenopathy, splenomegaly/hypersplenism, hepatomegaly/ascites, cytopenias, malabsorption, or protein-losing enteropathy with weight loss.21,22

In addition to acutely debilitating symptoms, systemic mastocytosis can have detrimental long-term outcomes8,10,23

Advanced forms of systemic mastocytosis associated with poor overall survival8,a

ASM (n=41)
SM-AHN (n=138)
MCL (n=4)
  • Median follow-up was 20.7 months.
  • A later study with 23 MCL patients demonstrated a median overall survival for patients with MCL of 1.9 years, with a 10-year survival of 29.9%.10
Overall survival was examined in a retrospective study that included 342 consecutive adult patients with systemic mastocytosis (includes 183 adults with advanced systemic mastocytosis) seen at the Mayo Clinic between 1976 and 2007.8

Non-advanced forms of systemic mastocytosis can progress to advanced forms11,24,25,c

Data collected from the registry of the European Competence Network on Mastocytosis (ECNM) was used to calculate rates of disease progression for patients with indolent systemic mastocytosis and smoldering systemic mastocytosis.11

~5% of ISM patients progress to more advanced disease (SSM or advanced SM)
ISM (n=653)
~9% of SSM patients progress 
to more advanced disease (advanced SM)
One study cites the rate of progression and/or leukemic transformation in SSM is 18% (4/22)
ISM (n=653)

With progression

Without progression

  • Median follow-up of patients with typical indolent systemic mastocytosis was 4.2 years (range 0 to 31.4 years) and patients with smoldering systemic mastocytosis was 4.3 years (0.3 to 22 years).

Systemic mastocytosis severely impacts patients' lives, and can lead to psychosocial consequences and poor quality of life13,19


High unmet clinical need:

  • There are no approved treatment options for indolent systemic mastocytosis and no approved selective inhibitors for KIT D816V in advanced systemic mastocytosis21
  • 75% of patients with indolent systemic mastocytosis take ≥4 classes of medication to manage their disease26

Psychological consequences:

  • Patients live in fear of anaphylaxis or other symptom flare-ups, such as frequent diarrhea19
  • In a survey of 363 patients with systemic mastocytosis, 72% reported psychological impact13,19

Quality of life impact:

  • The sudden onset of gastrointestinal, cognitive, and anaphylactic symptoms severely impacts patients’ ability to perform regular work or daily activities19
  • In a survey of 101 patients with indolent or smoldering systemic mastocytosis19:
    • Over 80% of patients with indolent systemic mastocytosis reported being limited in doing work or daily activities
    • Over 50% of patients reported that daily activities were either “very much” or “quite a bit” limited
    • 63% of patients with indolent systemic mastocytosis reported that hobbies and leisure activities were either “very much” or “quite a bit” limited
Learn how to identify systemic mastocytosis through hallmark symptoms.

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