This is a Phase II, single-arm, single-center study evaluating Chidamide combined with a PD-L1 inhibitor, carboplatin, and etoposide as first-line therapy in extensive-stage small-cell lung cancer (ES-SCLC) patients. The primary objective is to assess Progression-Free Survival (PFS) per RECIST v1.1. Secondary objectives include Objective Response Rate (ORR), Disease Control Rate (DCR), Duration of Response (DOR), Overall Survival (OS), and safety. Approximately 36 participants will receive induction therapy (Chidamide + chemotherapy + PD-L1 inhibitor) for 4 cycles, followed by Chidamide maintenance until progression or unacceptable toxicity.
Age ≥18 and ≤75 years.
Histologically confirmed ES-SCLC, unsuitable for local radical therapy.
No prior systemic therapy for ES-SCLC.
ECOG performance status 0-1.
Factors significantly affecting oral drug absorption.
Prior HDAC inhibitor or immune checkpoint inhibitor therapy.
Known allergy to any study drug component.
Other malignancy within past 5 years (except certain cured cancers).