QLS31905 in Combination With CAPOX Versus Sintilimab in Combination With CAPOX as First-line Treatment in Patients With GC/GEJ

A Randomized, Open-label, Multicenter Phase III Clinical Study of QLS31905 in Combination With CAPOX Versus Sintilimab in Combination With CAPOX as First-line Treatment in Patients With Unresectable Locally Advanced or Metastatic CLDN18.2-positive, PD-L1 CPS < 5 Gastric or Gastroesophageal Junction Adenocarcinoma

This study is a randomized, open, multicenter phase III clinical study designed to compare the efficacy and safety of QLS31905 injection combined with CAPOX versus sintilimab combined with CAPOX in the first-line treatment of CLDN18.2 positive, PD-L1 CPS < 5 unresectable locally advanced or metastatic gastric or gastroesophageal junction adenocarcinoma.

Study Overview

• Status: Not yet recruiting
• Conditions: Gastric or Gastroesophageal Junction Adenocarcinoma
• Intervention / Treatment: Drug: Capecitabine; Drug: QLS31905; Drug: Oxaliplatin; Drug: Sintilimab

• Study Type: Interventional
• Enrollment (Estimated): 560
• Phase: Phase 3

Contacts and Locations

• Study Contact: Name: Lin Shen, PhD; Phone Number: 010-88196358; Email: doctorshenlin@sina.cn

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• Subjects voluntarily participate in the study and sign the informed consent form;
• Eastern Cooperative Oncology Group (ECOG) performance status score of 0-1;
• Expected survival time ≥ 12 weeks;
• Histologically or cytologically confirmed diagnosis of gastric or gastroesophageal junction adenocarcinoma;
• No prior systemic anti-tumor treatment for unresectable locally advanced or metastatic disease;
• At least one measurable lesion per RECIST v1.1;
• Patients with adequate cardiac, liver, renal function, etc.

Exclusion Criteria:

• Known history of allergy to any component of the study drug;
• Other second primary malignant neoplasm within 5 years;
• Significant cardiovascular and cerebrovascular disorders within 6 months before randomization;
• Haemorrhage requiring haemostatic treatment within 3 months prior to randomisation;
• Previous or current interstitial pneumonia, pulmonary fibrosis, pneumoconiosis, etc;
• Previous treatment targeting CLDN18.2;
• Patients with added risks associated with the study or may interfere with the interpretation of study results as determined by the investigator, or deemed unsuitable by the investigator.

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: QLS31905+Oxaliplatin+Capecitabine	Drug: Capecitabine; Capecitabine will be administered orally twice daily (bid).; Drug: QLS31905; QLS31905 will be administered every 3 weeks Intravenous infusion on day 1 of each cycle.; Drug: Oxaliplatin; Oxaliplatin will be administered every 3 weeks Intravenous infusion on day 1 of each cycle.
Active Comparator: Sintilimab+Oxaliplatin+Capecitabine	Drug: Capecitabine; Capecitabine will be administered orally twice daily (bid).; Drug: Oxaliplatin; Oxaliplatin will be administered every 3 weeks Intravenous infusion on day 1 of each cycle.; Drug: Sintilimab; Sintilimab will be administered every 3 weeks Intravenous infusion on day 1 of each cycle.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Progression free survival (PFS)	PFS is defined as the duration from randomization to the first imaging confirmation of progressive disease by Blinded Independent Central Review (BICR) evaluation or death due to any cause (whichever occurs first).	Up to 44 months

Collaborators and Investigators

• Sponsor: Qilu Pharmaceutical Co., Ltd.

Study record dates

Study Major Dates

• Study Start (Estimated): August 1, 2026
• Primary Completion (Estimated): September 1, 2028
• Study Completion (Estimated): August 1, 2029

Study Registration Dates

• First Submitted: July 16, 2026
• First Submitted That Met QC Criteria: July 16, 2026
• First Posted (Actual): July 21, 2026

Study Record Updates

• Last Update Posted (Actual): July 21, 2026
• Last Update Submitted That Met QC Criteria: July 16, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Organic Chemicals; Heterocyclic Compounds, 1-Ring; Heterocyclic Compounds; Nucleic Acids, Nucleotides, and Nucleosides; Coordination Complexes; Deoxycytidine; Cytidine; Pyrimidine Nucleosides; Pyrimidines; Nucleosides; Uracil; Pyrimidinones; Deoxyribonucleosides; Fluorouracil; Capecitabine; Oxaliplatin; sintilimab
• Other Study ID Numbers: QLS31905-302

Drug and device information, study documents

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