Study findings support the cost-effectiveness of widespread adoption of genetic testing for patients with newly diagnosed metastatic gastrointestinal stromal tumor (GIST; JAMA Netw Open. 2020;3[9]:e2013565. doi:10.1001/jamanetworkopen.2020.13565).
“[GIST] is frequently driven by oncogenic KIT variations. Imatinib targeting of KIT marked a new era in GIST treatment and ushered in precision oncological treatment for all solid malignant neoplasms. However, studies on the molecular biological traits of GIST have found that tumors respond differentially to imatinib dosage based on the KIT exon with variation,” wrote Sudeep Banerjee, MD, MAS, Department of Surgery, Division of Surgical Oncology, University of California, San Diego, and colleagues.
“Despite this knowledge, few patients undergo genetic testing at diagnosis, and empirical imatinib therapy remains routine,” they continued.
This study aimed to determine whether targeted gene testing (TGT) is a cost-effective diagnostic for patients with metastatic GIST from the US payer perspective. A Markov model was developed to compare the cost-effectiveness of TGT and tailored first-line therapy compared with empirical imatinib therapy for this patient population.
TGT-directed therapy was associated with a quality-adjusted life years (QALYs) increase of 0.10 at an increased cost of $9513 over empiric imatinib, leading to an incremental cost-effectiveness ratio of $92,100.
This increase in cost reflects a specific cohort of patients that necessitate more expensive treatment due to their genetic KIT alteration. However, there are also patients that, based on testing, need the least expensive dosing option. Further analysis found that therapy driven by TGT was cost-effective 70% of the time.
“These findings suggest that using genetic testing to match treatment of KIT variations to imatinib dosing is a cost-effective approach compared with empirical imatinib,” Dr Banerjee and colleagues concluded.—Jennifer Spector
