Predictive factors for the efficacy of cetuximab plus chemotherapy as salvage therapy in metastatic gastric cancer patients

We performed a retrospective study to evaluate the efficacy of cetuximab plus chemotherapy in metastatic gastric cancer (MGC) patients previously treated with chemotherapy and to investigate potential predictors of treatment efficacy in those patients. Thirty-two patients with MGC were included in this study. Cetuximab was delivered, often combined with irinotecan-based chemotherapy. Thirty patients were analyzed for K-ras mutations via direct sequencing of the tumor DNA. Patients were heavily pretreated with a median number of three previous lines of palliative chemotherapy (56% of the patients were refractory to all of the following drugs: fluoropyrimidines, cisplatin, irinotecan, oxaliplatin, and docetaxel) and 53% of the patients displayed poor performance status. Of 28 response-assessable patients, the overall response rate to cetuximab plus chemotherapy was 3.6% [95% confidence interval (CI) 0-10.5%] and the disease control rate was 28.6%. The median progression-free survival (PFS) was 1.7 months (95% CI 1.3-2.1 months), and the median overall survival (OS) was 3.2 months (95% CI 1.4-5.0 months). Multivariate analyses revealed that skin rash and performance status were significantly associated with PFS and OS. The presence of a K-ras mutation (13.3%) was not associated with either PFS or OS. Our study suggests that MGC patients with good performance status and skin rash benefit most from salvage cetuximab combined with chemotherapy, even in heavily pretreated status.