A significant finding from a newly published study in JAMA Oncology, indicates that nearly one-fourth of GIST patients with advanced disease initially treated with imatinib will survive for ten years or more.
The study, a follow-up of a randomized clinical trial of 695 adult GIST patients, was coordinated by SWOG, with participation from member and affiliate institutions from the National Clinical Trials Network, and was led by Dr. Michael Heinrich, MD of Knight Cancer Institute, Oregon Health and Science University. SWOG is an international research community supported by the National Cancer Institute (NCI).
Long-term clinical outcomes for patients with advanced gastrointestinal stromal tumors who were treated with imatinib mesylate at two dosage levels (400mg and 800mg) indicate the estimated 10-year progression free and overall survival rates were approximately 7% and 23% respectively.
The highest 10-year progression free and overall survival rates were found in patients with KIT exon 11-mutant tumors compared with patients whose tumors had a KIT exon-9 mutation or who had either no KIT mutations or mutations in the platelet-derived growth receptor gene (PDGFRA).
According to Dr. Heinrich, “This is a really exciting finding. Until Gleevec arrived on the scene 15 years ago, patients with advanced GISTs faced a life expectancy of 18 months. Now we’ve learned that some might live a decade or longer. And we’ve come to understand which class of patients benefit the most from Gleevec.” 1
The patients in the study were initially enrolled in the S0033 trial, a phase 3 trial that began in 2000. Results published in 2008 indicated that imatinib was a highly effective treatment for patients with advanced GIST.
Post-study data was obtained from 2011 to 2015. The research team performed DNA sequencing from tumor tissue samples obtained at the start of the clinical trial and stored in a biospecimen bank. The resequencing studies confirmed the hypothesis that most GISTs contain identifiable pathogenic mutations, underscoring both the need for mutational testing for patients and the value of tissue in GIST research.
The results challenge the research community to continue to investigate in order to develop equally effective treatment options for those with mutations that do not respond to Gleevec, and for those who develop resistance.
The Life Raft Group is cited for providing research funding to Dr. Heinrich for the study.
The abstract of the study can be accessed here.
- Study shows strong long-term survival rates for patients with GIST. Science Daily; Science Daily, 20 February, 2017.