A Study of Sintilimab or Placebo in Combination With Chemotherapy as Second-line Treatment for Patients With Stage IV Nonsquamous Non-small Cell Lung Cancer With Wild-type EGFR After Failure With Platinum-Containing Chemotherapy.

This prospective, single-center, randomized, controlled study will evaluate the efficacy and safety of sintilimab or placebo in combination with chemotherapy as second-line treatment for patients with stage IV nonsquamous non-small cell lung cancer with wild-type EGFR after failure with platinum-containing chemotherapy. Treatment may continue as long as participants are experiencing clinical benefit as assessed by the investigator, i.e., in the absence of unacceptable toxicity or symptomatic deterioration attributed to disease progression.