Five-year follow-up of nivolumab treatment in Japanese patients with esophageal squamous-cell carcinoma (ATTRACTION-1/ONO-4538-07)

Background: In the phase II ATTRACTION-1 study, nivolumab demonstrated a promising antitumor activity among Japanese patients with treatment-refractory advanced esophageal cancer. Here, we report the follow-up results of ATTRACTION-1 of > 5 years. Methods: We enrolled patients with esophageal cancer that was refractory or intolerant to a standard chemotherapy. Then, nivolumab (3 mg/kg) was administered every 2 weeks. The primary endpoint was a centrally assessed objective response rate. Results: Nivolumab was administered to 65 patients with esophageal squamous-cell carcinoma (ESCC). The centrally assessed objective response rate was 17.2%. The overall survival rates at 3 and 5 years were 10.9% and 6.3%, respectively. Three-year survivors tended to have more reduced target lesions. A total of 63.1% of the patients exhibited treatment-related adverse events, and no new safety signal was observed. Patients with select adverse events tended to have better overall survival than those without. No apparent chronological order was observed between the first response and the onset of select adverse events. Conclusion: Our follow-up analysis of more than 5 years is currently the longest and is the first to demonstrate that nivolumab has long-term efficacy and safety for advanced ESCC.