A Single-center, Single-arm, Prospective Clinical Study to Evaluate the Efficacy and Safety of Serplulimab in Combination With Platinum-based Chemotherapy and Bayer Aspirin in Previously Untreated Patients With Extensive-stage Small Cell Lung Cancer.

In 2020, global cancer burden data showed 2.2 million new cases of lung cancer, ranking second, with 1.8 million deaths, far surpassing other cancer types and ranking first in cancer-related mortality. In 2020, China reported 820,000 new cases of lung cancer, with 710,000 deaths, accounting for 23.8% of all cancer deaths, making lung cancer the leading cause of cancer incidence and mortality in the country. Small cell lung cancer (SCLC), originating from neuroendocrine-differentiated epithelial cells, accounts for 15-20% of all lung cancers. Using the Veterans Administration (VA) staging system, SCLC is classified into limited-stage and extensive-stage disease. The majority of patients present with symptoms related to metastatic lesions at diagnosis, and only 30-40% are diagnosed at the limited stage. Extensive-stage patients, due to widespread metastasis and poor physical condition, often can only receive supportive care, resulting in shorter survival times.

Based on theoretical foundations, cytotoxic chemotherapy kills tumor cells (TC), exposing the immune system to high levels of tumor antigens. Therefore, compared to standard chemotherapy alone, activating tumor-specific T-cell immunity by inhibiting the PD-L1/PD-1 signaling pathway may provide deeper and more durable responses. Recent studies have explored the potential of combining immunotherapy with chemotherapy as a first-line treatment for extensive-stage small cell lung cancer (ES-SCLC).

Serplulimab is an innovative PD-1 inhibitor developed by Henlius, a recombinant humanized IgG4 monoclonal antibody. It has characteristics such as structural stability, weak antibody-dependent cellular cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC), moderate antibody-dependent cellular phagocytosis (ADCP) effects, large epitope binding area, high affinity, slow dissociation, strong anti-tumor activity, and low immunogenicity. Clinical studies involving serplulimab combined with chemotherapy as a first-line treatment for extensive-stage small cell lung cancer have been conducted to evaluate its safety and efficacy.

Aspirin (ASP), originally extracted from willow bark, is a small molecule compound with various effects such as antipyretic, anti-inflammatory, analgesic, and antiplatelet aggregation. In recent years, research has discovered new anti-cancer effects of aspirin, and it has been confirmed to promote tumor cell apoptosis. Additionally, preclinical evidence suggests that antiplatelet drugs and immune checkpoint inhibitors (ICIs) may have potential synergistic effects, which warrant further investigation in the context of lung cancer treatment.

PD-1 inhibitors, as the standard first-line treatment for extensive-stage small cell lung cancer, have been proven in numerous studies to have good efficacy and safety. Aspirin, as a classic anticoagulant, has advantages such as safety, affordability, and easy availability. Lung cancer patients are inherently in a hypercoagulable state, and if aspirin's synergistic anti-tumor effects and its potential to reduce adverse events such as fever and thrombosis can be further confirmed, it will have a significant impact on the treatment of ES-SCLC patients, potentially achieving enhanced therapeutic effects. Therefore, we plan to conduct this observational Phase II study to evaluate the efficacy and safety of combining the PD-1 inhibitor serplulimab, platinum-based chemotherapy, and Bayer aspirin as first-line treatment for extensive-stage small cell lung cancer.