SKB500 Combinations in Patients With Small Cell Lung Cancer

A Phase II, Multicenter, Open-Label Study to Evaluate the Safety and Efficacy of SKB500 Combinations in Patients With Small Cell Lung Cancer

The purpose of this study is to assess the safety, tolerability and preliminary antitumor activity of SKB500 combinations in patients with small cell lung cancer. The study is divided into two parts. Part 1 will be the safety run-in phase, and Part 2 will be the cohort expansion phase.

Study Overview

• Status: Recruiting
• Conditions: Small Cell Lung Cancer
• Intervention / Treatment: Drug: SKB500 Powder for Injection; Drug: KL-A167 Injection; Drug: Carboplatin Injection; Drug: Etoposide Injection

• Study Type: Interventional
• Enrollment (Estimated): 80
• Phase: Phase 2

Contacts and Locations

• Study Contact: Name: Yan Qing; Phone Number: 028-67255480; Email: qingyan@kelun.com

Study Locations

• China
  • Guangdong
    • Guangzhou, Guangdong, China
      • Recruiting
      • Guangdong Provincial People's Hospital
      • Contact: Yilong Wu; Phone Number: 020 83877855; Email: syylwu@live.cn

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

1. Male or female participants between 18 and 75 years old.

2. Histologically or cytologically confirmed Extensive-stage small cell lung cancer (ES-SCLC):

   • Cohort 1: participant has received or not received prior systemic treatment, with no more than 1 prior systemic therapy in the extensive stage.
   • Cohort 2~3: participant has received no prior systemic treatment.
3. Agree to provide fresh or archival tumor tissue for biomarker analysis.
4. Has at least one measurable lesion according to Response Evaluation Criteria in Solid Tumors (RECIST) Version 1.1.
5. Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1.
6. Life expectancy >= 12 weeks.
7. Has adequate organ and bone marrow functions.
8. Has recovered to grade ≤ 1 of prior anti-cancer treatment toxicities.
9. Effective contraceptive methods should be used during the study and for 6 months after the end of treatment.
10. Voluntarily join this study, sign the informed consent form, and can comply with the protocol-specified visits and procedures.

Exclusion Criteria:

1. The pathology suggests the presence of both non-small cell carcinoma and small cell carcinoma components.
2. Has previously received medications with the same target or the same toxins.
3. Presence of spinal cord compression or clinically active central nervous system metastases.
4. Presence of clinical symptoms caused by tumor invasion or compression of important organs and blood vessels.
5. Severe infection within 4 weeks or active infection requiring systemic anti-infective treatment within 2 weeks prior to the first dose.
6. With peripheral neuropathy of grade ≥ 2.
7. History of any serious, life threatening, or permanently discontinuing adverse events mediated by immunotherapy, including infusion reactions.
8. Presence of uncontrolled concurrent diseases, including but not limited to decompensated liver cirrhosis, nephrotic syndrome, uncontrolled metabolic disorders, Severe active peptic ulcer, gastrointestinal bleeding, gastrointestinal perforation, intestinal obstruction, etc.
9. Serious or uncontrolled heart disease or clinical symptoms requiring treatment.
10. History of interstitial lung disease (ILD) /noninfectious pneumonitis that require steroid treatment, or currently has ILD/noninfectious pneumonitis.
11. Clinical severe lung damage caused by concurrent lung disease.
12. Uncontrolled hypertension, diabetes, or repeated drainage of pleural effusion/pericardial effusion/ abdominal effusion.
13. Pregnant or lactating women.
14. Rapid disease deterioration in the screening process.

Study Plan

How is the study designed?

Design Details

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

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: 1. SKB500+KL-A167; Participants will receive KL-A167 followed by SKB500	Drug: SKB500 Powder for Injection; SKB500 will be administered as an intravenous (IV) infusion, every 3 weeks on Day 1 of each 21-day cycle and the dose will be determined based on the efficacy and safety data from the SKB500-I-01 study.; Drug: KL-A167 Injection; KL-A167 will be administered as an intravenous (IV) infusion every 3 weeks on Day 1 of each 21-day cycle (1200mg)
Experimental: 2. SKB500 +KL-A167+Carboplatin; Participants will receive KL-A167 followed by SKB500 with Carboplatin	Drug: SKB500 Powder for Injection; SKB500 will be administered as an intravenous (IV) infusion, every 3 weeks on Day 1 of each 21-day cycle and the dose will be determined based on the efficacy and safety data from the SKB500-I-01 study.; Drug: KL-A167 Injection; KL-A167 will be administered as an intravenous (IV) infusion every 3 weeks on Day 1 of each 21-day cycle (1200mg); Drug: Carboplatin Injection; Carboplatin will be administered as an intravenous (IV) infusion every 3 weeks on Day 1 of each 21-day cycle（AUC 5, Cycles 1-4)
Experimental: 3. SKB500+KL-A167+Carboplatin+Etoposide; Participants will receive KL-A167 followed by SKB500, Carboplatin with Etoposide	Drug: SKB500 Powder for Injection; SKB500 will be administered as an intravenous (IV) infusion, every 3 weeks on Day 1 of each 21-day cycle and the dose will be determined based on the efficacy and safety data from the SKB500-I-01 study.; Drug: KL-A167 Injection; KL-A167 will be administered as an intravenous (IV) infusion every 3 weeks on Day 1 of each 21-day cycle (1200mg); Drug: Carboplatin Injection; Carboplatin will be administered as an intravenous (IV) infusion every 3 weeks on Day 1 of each 21-day cycle（AUC 5, Cycles 1-4); Drug: Etoposide Injection; Etoposide will be administered as an intravenous (IV) infusion every 3 weeks on Day 1, 2, and 3 of each 21-day cycle (100 mg/m^2, Cycles 1-4).

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Incidence and severity of adverse events (AEs)	Incidence and severity of adverse events (AEs) graded by Common Terminology Criteria for Adverse Events (CTCAE) v5.0	up to 24 months
Progression-free survival (PFS)	Progression-free survival (PFS) was defined as the time from baseline to the earliest date of the first objective documentation of progressive disease (PD) or death due to any cause.	up to 24 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Objective Response Rate (ORR)	Objective Response Rate (ORR) is the percentage of participants who achieved a best overall response of Complete Response (CR) or Partial Response (PR), assessed by Investigator based on RECIST version 1.1.	up to 24 months
Duration of response (DOR)	Duration of Response (DOR) was defined as the time from the date of the first documentation of objective response (complete response [CR] or partial response [PR]) to the date of the first objective documentation of progressive disease (PD) or death due to any cause. DoR was measured for responding subjects (PR or CR) only.	up to 24 months
Disease control rate (DCR)	Disease control rate (DCR) was defined as the sum of complete response (CR) rate, partial response (PR) rate, and stable disease (SD) rate. As per RECIST v1.1, CR was defined as a disappearance of all lesions, PR was defined as at least a 30% decrease in the sum of diameters of target lesions, and stable disease (SD) was defined as neither sufficient shrinkage to qualify for PR nor sufficient increase to qualify for progressive disease.	up to 24 months
Overall Survival (OS)	The time from first dose to death from any cause.	up to 24 months
Pharmacokinetic Parameter Maximum Plasma Concentration (Cmax) of SKB500-ADC, SKB500-TAB and free payload		Cycle 1-4, 6, 8,12,16, every 8 cycles starting from Cycle 16 Day 1: pre-dose, post-dose (each cycle is 21 days), up to 24 months
Pharmacokinetic Parameter Minimum Plasma Concentration (Cmin) of SKB500-ADC, SKB500-TAB and free payload		Cycle 1-4, 6, 8,12,16, every 8 cycles starting from Cycle 16 Day 1: pre-dose, post-dose (each cycle is 21 days), up to 24 months, up to 24 months
Anti-drug Antibodies (ADA) for SKB500		Cycle 1-4, 6, 8, 12, 16, every 8 cycles starting from Cycle 16 Day 1: pre-dose, (each cycle is 21 days), up to 24 months

Collaborators and Investigators

• Sponsor: Sichuan Kelun-Biotech Biopharmaceutical Co., Ltd.
• Investigators: Principal Investigator: Yilong WU, Guangdong Provincial People's Hospital

Study record dates

Study Major Dates

• Study Start (Actual): January 30, 2026
• Primary Completion (Estimated): December 31, 2028
• Study Completion (Estimated): December 31, 2029

Study Registration Dates

• First Submitted: November 25, 2025
• First Submitted That Met QC Criteria: December 8, 2025
• First Posted (Actual): December 22, 2025

Study Record Updates

• Last Update Posted (Actual): May 8, 2026
• Last Update Submitted That Met QC Criteria: May 5, 2026
• Last Verified: May 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; Therapeutics; Drug Administration Routes; Drug Therapy; Hydrocarbons; Hydrocarbons, Cyclic; Carbohydrates; Podophyllotoxin; Tetrahydronaphthalenes; Naphthalenes; Polycyclic Aromatic Hydrocarbons; Hydrocarbons, Aromatic; Polycyclic Compounds; Glucosides; Glycosides; Coordination Complexes; Etoposide; Carboplatin; Injections; 18-O-demethylcervinomycin A2
• Other Study ID Numbers: SKB500-II-02

Drug and device information, study documents

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