This study is a prospective, single-arm, phase II clinical trial, with 1-year PFS as the endpoint, to evaluate the efficacy and associated toxicity of Pamiparib as single-agent consolidation treatment in patients with limited-stage small cell lung cancer(LS-SCLC) patients who have not progressed following platinum-based concurrent chemoradiotherapy(cCRT) .

Inclusion Criteria:

• The patient or a legally authorized representative must provide study-specific informed consent prior to study entry, had good compliance and cooperated with the follow-up.
• Age at least 18 years
• Pathologically (histologically or cytologically) proven diagnosis of limited stage small cell lung cancer (Stage Tx, T1-T4, N0-3, M0, American Joint Committee on Cancer [AJCC] staging, 8th edition [Ed.]), within 60 days prior to registration
• Patients must have had measurable disease (per Response Evaluation Criteria in Solid Tumors [RECIST], version 1.1) prior to the required cycle of cCRT
• Patients must be free of disease progression and not be able to receive other antitumor therapy within 6 weeks of completion of cCRT
• Patients must submit archived or freshly biopsied tumor tissue (formalin-fixed, paraffin-embedded tissue block or approximately 15 unstained sections [must have >8 sections]) along with the relevant pathology report.
• Eastern Cooperative Oncology Group (ECOG) performance status of 0-2 within 30 days prior to registration
• Patient life expectancy must be >12 weeks

Exclusion Criteria:

• Mixed SCLC or NSCLC confirmed by histology
• Previous tumor resection for LS-SCLC
• Any patient treatable by surgery or stereotactic body radiation therapy/stereotactic ablative radiation therapy should be excluded
• Expected to receive any other form of anti-tumor therapy during the study period
• Previous treatment with PARP inhibitor drugs
• Any active malignancy within 2 years prior to enrollment, excluding the specific cancers being studied in this study and locally recurrent cancers that have been cured (eg, resected basal or squamous cell skin cancer, superficial bladder cancer, cervical cancer carcinoma in situ or carcinoma in situ of the breast)
• Women who are pregnant, breastfeeding, or planning to become pregnant during the study
• Concurrent participation in another therapeutic clinical trial