New data shows avapritinib offers lasting relief for people with indolent systemic mastocytosis (SM), easing the skin lesions and symptoms that define the disease, according to a recent abstract published in the Journal of the American Academy of Dermatology.
Indolent SMIndolent SM A subtype of nonadvanced SM caused by the abnormal accumulation of mast cells in the bone marrow and other organs. Indolent SM accounts for around 90% of SM cases. is driven in most cases by a single mutation — known as D816V — in a gene called KIT. That glitch prompts mast cells, the immune cells behind allergic reactions, to multiply and accumulate throughout the body, including in the skin; for many patients, these extra mast cells cause itchy reddish-brown spots on the skin. Avapritinib is designed to switch off the faulty KIT protein.
The researchers examined skin symptoms of patients from the PIONEER clinical trial. In the trial, patients with moderate to severe symptoms took a single 25-milligram avapritinib pill each day.
The researchers took photographs of the torso and thighs, front and back, at six months and again at 12 months. An artificial intelligence program measured how much skin their lesions covered, while a panel of experts judged their color.
By six and 12 months, lesions had shrunk and faded significantly, with lasting improvements in the most affected regions.
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Patients also rated their own itching, flushing and spots on a standard questionnaire, first at the outset of treatment and then for roughly three and a half years. Researchers compared those early scores with a separate survey of quality of life, and tracked side effects along the way.
At the time of the analysis, patients had stayed on the drug a median of 40 months. Symptom relief persisted across the full three and a half years of follow-up.
“Avapritinib elicited long-term disease modification seen as durable improvements in ISM-related skin lesions (area and color) and symptoms,” the researchers said.
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Avapritinib is sold under the brand name Ayvakit and is manufactured by Blueprint Medicines, a Sanofi company.
