A Study Comparing QLC5508 in Combination With QL2107 Versus Tislelizumab Plus Platinum-based Chemotherapy in Participants Wih Treatment-naïve Extensive-Stage Small Cell Lung Cancer

A Phase III, Randomized, Controlled, Open-label Clinical Study to Compare the Efficacy and Safety of QLC5508 in Combination With QL2107 Versus Tislelizumab Plus Platinum-based Chemotherapy as First-line Treatment in Participants With Extensive-stage Small Cell Lung Cancer

This trial is a Phase III, randomized, open-label, multicenter study to evaluate the efficacy and safety of QLC5508 in combination with QL2107 versus Tislelizumab plus platinum and etoposide as first-line treatment in participants with extensive-stage small cell lung cancer.

Study Overview

• Status: Not yet recruiting
• Conditions: Extensive-stage Small Cell Lung Cancer
• Intervention / Treatment: Drug: QLC5508; Drug: QL2107; Drug: Tislelizumab; Drug: Carboplatin; Drug: Cisplatin; Drug: Etoposide

• Study Type: Interventional
• Enrollment (Estimated): 556
• Phase: Phase 3

Contacts and Locations

• Study Contact: Name: Haiying Yu, Bachelor; Phone Number: +86-17821799566; Email: haiying.yu@qilu-pharma.com

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

1. Age ≥18 years.
2. Participants with histologically or cytologically confirmed Extensive-Stage Small Cell Lung Cancer (ES-SCLC) per the Veterans Administration Lung Cancer Study Group (VALG) staging system.
3. No prior systemic treatment for ES-SCLC.
4. At least one extracranial measurable lesion according to RECIST v1.1.
5. Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1, without deterioration within 2 weeks prior to the first dose of study treatment.
6. Life expectancy ≥12 weeks.
7. Has adequate organ function.
8. Male and female participants of reproductive/childbearing potential must agree to avoid pregnancy.
9. Voluntarily sign the written informed consent form and comply with the protocol requirements.

Exclusion Criteria:

1. Has received or undergoing any of the following treatment:

   Previous or current treatment with B7-H3 targeted therapy. Previous or current treatment with topoisomerase I inhibitors.

2. Participants with transformed Non-Small Cell Lung Cancer (NSCLC), epidermal growth factor receptor (EGFR) mutation-positive NSCLC that has transformed to SCLC, or mixed SCLC-NSCLC histology.
3. Presence with active brain metastases, leptomeningeal metastasis, brainstem metastasis or spinal cord compression.
4. Radiotherapy with a limited field of radiation within 2 weeks prior to the study treatment; more than 30% of the bone marrow irradiation or large-scale radiotherapy within 4 weeks prior to study treatment.
5. Major surgery within 4 weeks prior to the study treatment.
6. Unresolved AEs ≥ Grade 2 (CTCAE v6.0) from prior therapy.
7. Previous or concurrent primary malignancies.
8. History of severe heart disease or cerebrovascular disease.
9. History of Severe or uncontrolled hypertension or diabetes mellitus.
10. Severe infection within 4 weeks prior to study treatment; or uncontrolled active infection at screening.
11. Known or suspected interstitial lung disease/non-infectious pneumonitis; or other moderate to severe pulmonary diseases that significantly impair respiratory function and may interfere with the detection or management of drug-related pulmonary toxicity.
12. Known history of pre-existing or newly diagnosed autoimmune disease.
13. History of severe neuropathy or mental disorders.
14. History of severe hypersensitivity reaction, severe infusion reaction or idiosyncrasy to drugs chemically related to study drugs or any components of the study drugs.
15. Unlikely to comply with study procedures and requirements in the opinion of the investigator.
16. Any disease or condition that, in the opinion of the investigator, would compromise participant safety or interfere with study assessments.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: QLC5508 in combination with QL2107	Drug: QLC5508; QLC5508 will be administered intravenously once every 3 weeks. Treatment will continue until disease progression or unacceptable toxicity, whichever occurs first.; Drug: QL2107; QL2107 will be administered intravenously once every 3 weeks. Treatment will continue until disease progression or unacceptable toxicity. The maximum treatment duration for QL2107 will be 2 years.
Active Comparator: Tislelizumab in Combination with Platinum-based Chemotherapy	Drug: Tislelizumab; Tislelizumab will be administered intravenously once every 3 weeks. Treatment will continue until disease progression or unacceptable toxicity. The maximum treatment duration for Tislelizumab will be 2 years.; Drug: Carboplatin; Carboplatin will be administered intravenously once every 3 weeks. Carboplatin treatment will be administered for up to 4 cycles.; Drug: Cisplatin; Cisplatin will be administered intravenously once every 3 weeks. Cisplatin treatment will be administered for up to 4 cycles.; Drug: Etoposide; Etoposide will be administered intravenously once every 3 weeks. Etoposide treatment will be administered for up to 4 cycles.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Overall survival (OS)	OS is defined as the duration from the date of randomization to the date of death due to any cause.	Up to approximately 36 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Progression-free survival (PFS)	PFS is defined as the duration from the date of randomization to the date of first documented progressive disease (PD) based on investigator assessment, or death from any cause, whichever occurs first.	Up to approximately 36 months
Objective response rate (ORR)	ORR is defined as the percentage of participants achieved complete response or partial response as assessed according to RECIST v1.1 criteria.	Up to approximately 36 months
Duration of response (DOR)	DOR is defined as the duration from the first documented objective response to the first documented disease progression or death from any cause, whichever occurs first.	Up to approximately 36 months
Disease control rate (DCR)	DCR is defined as the percentage of participants achieved complete response, partial response, or stable disease as assessed according to RECIST v1.1 criteria.	Up to approximately 36 months
6-month PFS rate	The 6-month PFS rate is defined as the proportion of participants who have not experienced PD and who are alive at 6 months from the date of randomization.	Up to approximately 36 months
12-month PFS rate	The 12-month PFS rate is defined as the proportion of participants who have not experienced PD and who are alive at 12 months from the date of randomization.	Up to approximately 36 months
12-month OS rate	The 12-month OS rate is defined as the proportion of participants who are alive at 12 months from the date of randomization.	Up to approximately 36 months
24-month OS rate	The 24-month OS rate is defined as the proportion of participants who are alive at 24 months from the date of randomization.	Up to approximately 36 months
Treatment Emergent Adverse Event (TEAE)	TEAEs are defined as any adverse event (AE) that occurs after the initiation of study treatment, or any pre-existing condition that worsens in severity or frequency after the initiation of study treatment, regardless of the causal relationship to the study treatment. TEAEs will be graded and summarized by type, frequency, and severity according to the National Cancer Institute Common Terminology Criteria for Adverse Events (NCI CTCAE), version 6.0.	Up to approximately 36 months

Collaborators and Investigators

• Sponsor: Qilu Pharmaceutical Co., Ltd.

Study record dates

Study Major Dates

• Study Start (Estimated): October 15, 2026
• Primary Completion (Estimated): March 15, 2029
• Study Completion (Estimated): June 15, 2030

Study Registration Dates

• First Submitted: August 30, 2026
• First Submitted That Met QC Criteria: August 30, 2026
• First Posted (Actual): September 3, 2026

Study Record Updates

• Last Update Posted (Actual): September 3, 2026
• Last Update Submitted That Met QC Criteria: August 30, 2026
• Last Verified: August 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Neoplasms by Site; Neoplasms; Respiratory Tract Diseases; Lung Diseases; Respiratory Tract Neoplasms; Thoracic Neoplasms; Lung Neoplasms; Carcinoma, Bronchogenic; Bronchial Neoplasms; Small Cell Lung Carcinoma; Organic Chemicals; Hydrocarbons; Hydrocarbons, Cyclic; Carbohydrates; Podophyllotoxin; Tetrahydronaphthalenes; Naphthalenes; Polycyclic Aromatic Hydrocarbons; Hydrocarbons, Aromatic; Polycyclic Compounds; Glucosides; Glycosides; Inorganic Chemicals; Chlorine Compounds; Nitrogen Compounds; Coordination Complexes; Platinum Compounds; Etoposide; Carboplatin; Cisplatin; tislelizumab
• Other Study ID Numbers: QLC5508-304

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No