Long-term outcomes of toripalimab plus chemotherapy and radiotherapy for treatment-naive advanced esophageal squamous cell carcinoma: Results from a phase II trial.

e16028 Background: This study presents the long-term overall survival outcomes from a phase II clinical trial investigating the efficacy of toripalimab in combination with paclitaxel, carboplatin, and radiotherapy for the treatment of patients with stage IV esophageal squamous cell carcinoma (ESCC). Methods: This was an open-label, single-center, single-arm phase II clinical trial conducted in patients aged 18–75 years with previously untreated stage IV ESCC. Participants received chemotherapy comprising four cycles of paclitaxel (135–175 mg/m 2 ) and carboplatin every three weeks. Toripalimab (240 mg) was administered intravenously every three weeks for 12 months or until disease progression or intolerable toxicity. Radiotherapy was initiated during the third chemotherapy cycle, delivering a total dose of 50–50.4 Gy in 25–28 fractions to the primary lesions and 30–40 Gy in 3–5 fractions to metastatic sites. The primary outcome of the study was progression-free survival (PFS), while secondary outcomes included objective response rate (ORR), disease control rate (DCR), duration of response (DoR), one- and two-year overall survival (OS) rates, and adverse events. This trial was registered at Chictr.org.cn under registration number ChiCTR2100046715. Results: A total of 33 participants were enrolled in this study, with 26 (78.8%) completing the full course of radiotherapy and chemotherapy. At the time of analysis, all patients had updated follow-up data, and there were no losses to follow-up. The median follow-up duration was 34.1 months (IQR: 29.6–41.8). A total of 25 patients had died by the time of analysis. In the intent-to-treat (ITT) population, the updated median OS was 16.3 months (95% CI: 1.4–31.2), while in the per-protocol (PP) population, consisting of patients who completed radiotherapy, the median OS was 26.9 months (95% CI: 24.7–29.2). The two-year OS rates were 48.5% and 68.5% for the ITT and PP populations, respectively. Conclusions: After nearly three years of follow-up, the addition of radiotherapy to first-line chemo-immunotherapy in treatment-naive advanced ESCC patients continues to show clinically significant improvements in OS and a durable antitumor response. Clinical trial information: ChiCTR2100046715 .