Use of PD-1 and PD-L1 inhibitors after first-line therapy in esophageal cancer patients in the US

Introduction Esophageal cancer (EC) makes up 3.2% of all cancers but ranks sixth among cancer-related deaths worldwide. This real-world analysis determined the use of PD-1/PD-L1 (PD[L]1) inhibitors in EC patients after receiving first-line therapy. Methods Newly diagnosed EC patients initiating first-line treatment were identified in the IBM MarketScan administrative claims databases during the study period (1 May 2015 to 31 October 2020) using ICD-9/ICD-10 codes. Patients were assigned to either the chemotherapy only, radiation only, chemotherapy plus radiation (chemoradiation), or esophageal transhiatal/transthoracic surgery cohorts. Results 7276 EC patients started first-line therapy (chemotherapy only = 2502, radiation only = 3355, chemoradiation = 1180, surgery = 239). The average age at diagnosis was 62 years and 23% were female. The median time from start of first-line therapy to utilization of a PD(L)1 inhibitor was 259 days. Pembrolizumab (72%) was the most frequently used PD(L)1 inhibitor across the three cohorts, followed by nivolumab (25%). Furthermore, the number of patients receiving a PD(L)1 inhibitor increased each year with the majority (73%) of use occurring between 2018 and 2020. Discussion Findings from this real-world study suggest that PD(L)1 inhibitors are increasingly used after first-line therapies in EC, especially among patients initially receiving chemotherapy only. New immunological therapies such as PD(L)1 inhibitors hold great promise for patients with solid tumors. A clearer understanding of their real-world utilization is critical.