Avapritinib offered significantly better outcomes for patients with advanced systemic mastocytosis (SM) compared to midostaurin or best available therapy, according to results from a retrospective study presented recently at the American Society of Hematology’s annual meeting and exposition.
Patients receiving avapritinib experienced longer overall survival and duration of treatment across both first-line and later-line treatment settings, offering critical insights into its efficacy and potential as a preferred treatment option for advanced SM, the study said.
What is the difference between advanced and nonadvanced SM?
Nonadvanced SM comprises the indolent SM and smoldering SM subtypes. Advanced SM includes aggressive SM, SM with an associated hematologic neoplasm and mast cell leukemia.
“This study supports the use of avapritinib as 1L [first-line] treatment for AdvSM [advanced SM], demonstrating significant [overall survival] and [duration of therapy] benefits compared to patients treated with 1L midostaurin,” study authors said. They added: “These data offer important insights on the superior efficacy of avapritinib as compared to available therapies for [patients] with AdvSM and may help inform treatment decisions.”
Read more about SM therapies
Advanced SM is a rare and progressive blood disorder caused by the accumulation of abnormal mast cells in the body. It often involves mutations in the KIT D816V gene, which drives the disease. Symptoms range from fatigue and abdominal pain to severe organ damage, significantly affecting quality of life. Treatment aims to manage symptoms and improve survival.
In the first-line setting, the study compared avapritinib with midostaurin, a multikinase inhibitor previously used as a common treatment for advanced SM. Patients treated with avapritinib had a median overall survival that was not reached during the study’s 26-month follow-up, while midostaurin patients had a median overall survival of 32.2 months. Similarly, the median duration of treatment for avapritinib was 41.3 months, compared to 13 months for midostaurin, indicating patients could stay on avapritinib significantly longer.
For patients receiving second or later treatments, avapritinib was compared to best available therapy, which included therapies such as midostaurin, cladribine and hydroxyurea. Patients receiving avapritinib had a median overall survival of more than 30 months, compared to 17.9 months for those on best available therapy. The duration of treatment difference was even more pronounced, with patients receiving avapritinib remaining on therapy for a median of 21.3 months, compared to 5.4 months for patients receiving best available therapy.
The results highlighted the ability of avapritinib to improve both survival and treatment continuity in a disease with limited therapeutic options. The research underscored the importance of selecting targeted therapies such as avapritinib to improve outcomes for people living with the challenging condition, offering hope for better quality of life and longer survival.
