This single-arm, open-label, Phase II study assesses first-line QL1706 + bevacizumab (anti-VEGF) + platinum/etoposide chemotherapy to treat naïve ES-SCLC patients.The main questions it aims to answer are: Evaluate efficacy and safety of this quadruplet regimen in ES-SCLC Explore correlations between tumor biomarkers and treatment efficacy Participants will: Histologically or cytologically confirmed, treatment-naïve extensive-stage small cell lung cancer (ES-SCLC). Willing to provide archived or fresh tumor tissue samples. If unavailable, enrollment may proceed per investigator assessment. At least one measurable lesion per RECIST v1.1
Small cell lung cancer (SCLC) is a highly aggressive malignancy, accounting for 13-15% of all lung cancers. Approximately two-thirds of patients present with distant metastases at diagnosis, defined as extensive-stage SCLC (ES-SCLC). Prognosis remains poor, with median overall survival (mOS) of 12-15 months despite standard first-line chemotherapy using etoposide plus cisplatin/carboplatin (EP/EC), which offers limited benefit (mOS \~10 months; median progression-free survival \[mPFS\] \~5 months). Immune checkpoint inhibitors (ICIs) have improved outcomes modestly. IMpower133, KEYNOTE-604, RATIONALE-312, and EXTENTORCH trials confirmed the benefit of adding PD-1/PD-L1 inhibitors to chemotherapy, but the survival plateau remains. Dual immune checkpoint blockade strategies, including PD-1/PD-L1 with CTLA-4 inhibitors, have not significantly improved outcomes and pose higher toxicity, as seen in CASPIAN and CheckMate451 studies. Antiangiogenic therapy offers another promising direction. Studies such as SALUTE, ACTION-2, and BEAT-SC have explored bevacizumab or anlotinib combined with chemo-immunotherapy, showing potential survival gains. Notably, the ETER701 study using a four-drug combination achieved mOS of 19.3 months, although with increased adverse events. QL1706 (Aito combination antibody) is a novel bifunctional antibody targeting PD-1 and CTLA-4 in a 2:1 fixed ratio, designed to optimize synergy while reducing CTLA-4 toxicity. Approved in 2024, it has demonstrated efficacy and tolerability in multiple solid tumors. In NSCLC, QL1706 combined with chemotherapy and antiangiogenic therapy showed mPFS up to 8.5 months and mOS of 26.5 months. To date, no clinical data exist for QL1706 combined with antiangiogenic therapy and chemotherapy in ES-SCLC. A phase II, open-label, single-arm clinical trial is proposed to evaluate its efficacy and safety as first-line treatment. This study aims to explore a new therapeutic strategy to overcome the current survival limitations in ES-SCLC.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
TREATMENT
Masking
NONE
Enrollment
56
Participants will receive QL1706 (5 mg/kg, IV, day 1), bevacizumab (7.5 mg/kg, IV, day 1), etoposide (100 mg/m², IV, days 1-3), plus either cisplatin (75 mg/m² split over days 1-2, IV) or carboplatin (AUC=5, IV, day 1) every 21 days for 4-6 cycles. Dose adjustments may be made based on clinical judgment. Patients who do not experience disease progression or intolerable toxicity will proceed to maintenance therapy with QL1706 (5 mg/kg, IV, day 1) and bevacizumab (7.5 mg/kg, IV, day 1) every 21 days, continued until disease progression, unacceptable toxicity, consent withdrawal, investigator decision, loss to follow-up, death, or other protocol-defined criteria. All participants will receive dual-agent maintenance therapy.
National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, Beijing 100021
Beijing, Beijing Municipality, China
Progression-Free Survival (PFS)
PFS is defined as the time from the first dose of study treatment to the first documentation of disease progression according to RECIST v1.1 (as assessed by investigators) or death from any cause, whichever occurs first. Subjects who are alive without progression at the time of analysis will be censored at the date of the last tumor assessment.
Time frame: From enrollment to the end of monitoring at 2 years.
Overall Survival (OS)
OS is defined as the time from the first dose of study treatment to death from any cause. Subjects who are alive at the time of analysis will be censored at the date of last follow-up.
Time frame: From enrollment to the end of monitoring at 2 years.
Objective Response Rate (ORR)
ORR is defined as the proportion of subjects who achieve a complete response (CR) or partial response (PR) as per RECIST v1.1.
Time frame: From enrollment to the end of monitoring at 2 years.
Duration of Response (DoR)
DoR is defined as the time from the first documentation of CR or PR to the first documentation of disease progression or death.
Time frame: From enrollment to the end of monitoring at 2 years.
Disease Control Rate (DCR)
DCR is defined as the proportion of subjects who achieve CR, PR, or stable disease (SD) as their best overall response.
Time frame: From enrollment to the end of monitoring at 2 years.
The incidence of adverse events
Incidence, nature, and severity of adverse events (AEs), graded according to NCI-CTCAE v5.0, including immune-related AEs and serious AEs.
Time frame: From enrollment to the end of monitoring at 2 years
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