Retrospective study of the predictive value of target now^®in systemic therapy for metastatic colorectal and gastric carcinomas

Background: Predictive biomarkers for personalized treatment of neoplasms are suggested to be a major advancement in oncology and are increasingly used in clinical practice, albeit based on level II evidence. Target Now^®(TN) employs immunostaining and RNA expression on tumor samples to identify potentially beneficial or ineffective drugs. Objectives: To explore retrospectively the predictive value of TN for patients with colorectal and gastric carcinomas. Methods: The study group comprised colorectal and gastric carcinoma patients with TN test reports. We identified chemotherapy regimens given for stage IV disease for which TN reports indicated prediction. Protocols were classified as having clinical benefit (CB; i.e., stable disease or any objective response) or progressive disease, and this was compared with the TN prediction. Results: Nineteen patients – 12 colorectal and 7 gastric carcinomas – met the inclusion criteria. There were 26 evaluable treatment protocols; of 18 with a CB 15 were predicted to have a CB while 3 were predicted to have a lack of CB. Of eight protocols that had no CB, seven were predicted to have a CB and one a lack of CB. A chi-square test was non-significant (P = 0.78). An exploratory analysis yielded a positive predictive value of 68% and a sensitivity of 83% for the TN test. Conclusions: This study emphasizes the need for larger multicenter studies to validate the TN test before it is adopted into clinical practice.