Metronomic Oral Paclitaxel Plus PD-1/ PD-L1 Inhibitor Maintenance in Advanced Lung Cancer (PULSE Study)

Immune checkpoint inhibitor-based chemoimmunotherapy is a standard first-line treatment for advanced squamous non-small cell lung cancer and extensive-stage small cell lung cancer. However, many patients experience disease progression shortly after completing the chemotherapy component and entering the maintenance phase. More effective and tolerable maintenance strategies are therefore needed. Metronomic chemotherapy uses relatively low doses of cytotoxic treatment administered repeatedly over time. In addition to direct antitumor activity, metronomic paclitaxel may modulate the tumor immune microenvironment and enhance the effects of immune checkpoint inhibition. An oral paclitaxel formulation may also be more suitable for long-term maintenance treatment than intravenous paclitaxel because it avoids repeated intravenous infusions. This is a prospective, open-label, multicenter, nonrandomized, multi-cohort exploratory study. Participants must have completed four cycles of standard first-line chemoimmunotherapy and achieved complete response, partial response, or stable disease without disease progression. Cohort A will enroll approximately 67 participants with advanced squamous non-small cell lung cancer(sqNSCLC). Cohort B will enroll approximately 40 participants with extensive-stage small cell lung cancer(ES-SCLC). Both cohorts will receive oral paclitaxel solution at 100 mg/m² per dose, administered orally three times weekly, together with a PD-1 or PD-L1 inhibitor administered every 3 weeks according to the approved or guideline-recommended regimen. The maintenance immune checkpoint inhibitor should generally remain the same as that used during induction therapy. Treatment will continue until radiographic disease progression, unacceptable toxicity, withdrawal of consent, or another protocol-defined discontinuation criterion. Tumor assessments will generally be performed every 6 weeks, and safety assessments will generally be performed every 3 weeks. The primary endpoint is progression-free survival measured from the first dose of oral paclitaxel. The two cohorts will be analyzed independently, and no formal efficacy comparison between the two cohorts is planned. Exploratory analyses will evaluate circulating tumor DNA, peripheral immune-cell subsets, inflammatory and immune-related factors, and PD-1/PD-L1-related biomarkers.