Genomic abnormalities can be identified in individual patients with metastatic breast cancer, which can then lead to targeted therapy, investigators reported in the March issue of Lancet Oncology.
In a prospective study of 423 patients who had breast cancer with a metastasis accessible for biopsy, comparative genomic hybridization array was feasible in 283 patients and Sanger sequencing was feasible in 297 patients. A targetable genomic alteration was found in 195 patients (46%), most often PIK3CA mutation (25%), CCND1 amplification (18%), and FGFR1 amplification (12%), reported Dr. Fabrice André of Institut Gustave Roussy, Villejuif, France, and his associates.
Dr. Fabrice André
The primary endpoint – the ability to offer targeted therapy based on genomic sequencing – was achieved for 55 patients (13%). Of the 43 patients who ultimately received targeted therapy as a result of the genomic analyses, four (9%) had an objective response, and nine others (21%) had stable disease for more than 16 weeks. Grade 3 or higher adverse events related to biopsy were reported in four patients (Lancet Oncol. 2014;15:267-74).
The response rate was "disappointing," but the patient population had been heavily pretreated, the researchers noted.
The result "justifies the development of multiple strategies to improve efficacy of screening" for targeted therapy, the investigators said. They recommended improving algorithms for analyzing genomic data, using highly bioactive agents for targeted therapy, and combining therapies to delay drug resistance.
The study was sponsored by the French National Cancer Institute, Breast Cancer Research Foundation, Odyssea, and Operation Parrains Chercheurs. The authors reported no relevant financial conflicts of interest.