Because the number of cytotoxic agents available for the treatment of metastatic colorectal cancer (mCRC) is limited, rechallenge with the same chemotherapy agents can provide a continuum of treatment. This study investigated the efficacy and feasibility of oxaliplatin rechallenge in mCRC patients who had been previously exposed to oxaliplatin-based chemotherapy. Patients were included if they had mCRC and evaluable disease, had remained disease-free or progression-free for at least 6 months after the last dose of prior oxaliplatin-based therapy, and were retreated with oxaliplatin therapy. Between January 2009 and May 2014, 110 patients were retreated with oxaliplatin-based regimens; of these, 42 (38.2%) had received prior oxaliplatin as adjuvant chemotherapy and 68 (61.8%) as palliative chemotherapy. The overall response rate to oxaliplatin rechallenge was 30.9% (34/110), and the disease control rate was 68.2% (75/110), with one patient achieving complete response, 33 achieving partial response, and 41 having stable disease. Median progression-free survival and overall survival following oxaliplatin rechallenge were 5.9 months (95% confidence interval [CI], 4.4-7.4 months) and 18.5 months (95% CI, 14.0-23.0 months), respectively. Sixteen patients experienced grade 2 or 3 neuropathy. Ten patients experienced any grade hypersensitivity reaction within four cycles of treatment, including six who stopped treatment due to grade 3 or 4 hypersensitivity reactions. Rechallenge with oxaliplatin-based therapy may be an option for patients who achieve at least 6 months of disease-free or progression-free survival with prior oxaliplatin-based chemotherapy. However, neurotoxicity and hypersensitivity reactions should be carefully monitored in this setting.
Keywords: Chemotherapy; Metastatic colon cancer; Oxaliplatin; Rechallenge.