Number of patients, male	46
Number of patients, female	4
Stage	All patients were at stage IV
Age	Median (range): 61 (47-74) years
Number of prior systemic therapies	Median (range): 3.5 (1-6)
Performance Status: ECOG	0—14 1—36 2—0 3—0 Unknown—0
Other	In this study, 102 patients with advanced ESCC were screened between May 2017 and June 2020. Among these patients, 50 were ineligible. Eventually, a total of 52 patients were enrolled. One patient did not receive study treatment due to withdrawal of consent, and one patient was excluded from the efficacy analysis due to protocol violation that received concurrent radiotherapy. In total, anti-tumor activity and safety outcomes were analyzed in 50 patients (Table 1). The median age of enrolled patients was 61 years (range, 47-74); of these, most patients were male (46/59, 92.0%). Eastern Cooperative Oncology Group performance status score was 0 in 14 (28%) of 50 patients. All patients were at stage IV. Most patients received platinum-based doublet chemotherapy as first-line treatment, with 34.0% of them underwent paclitaxel and carboplatin chemotherapy. The data cutoff for safety and efficacy analysis was on February 26, 2021, with a median follow-up of 10.97 months (95% CI: 7.03-19.42). At the data cutoff, all patients had discontinued the protocol treatment, including completion of study (n = 25), disease progression (n = 15), AEs (n = 5), and loss to follow up (n = 5). The patients received a median of 3.5 cycles (range, 1-6) of study treatment.
Cancer types or histologic subtypes	Esophageal squamous cell carcinoma: 50