A Randomized, Controlled, Multi-center Phase II Study of Ivonescimab (AK112) plus Paclitaxel versus Paclitaxel with or without Ramucirumab as second-line therapy in subjects with advanced gastric or gastroesophageal junction（G/GEJ）cancer who failed immunochemotherapy
Voluntary written informed consent provided
Age ≥18 and ≤75 years, regardless of gender
Histologically or cytologically confirmed advanced or metastatic gastric adenocarcinoma or gastroesophageal junction adenocarcinoma
Prior treatment failure with PD-1/L1 inhibitor combined with platinum-based chemotherapy; no other systemic antitumor therapy allowed (only first-line therapy permitted, with initial immunotherapy duration ≥12 weeks).Note: Patients who previously received adjuvant/neoadjuvant PD-1 inhibitor plus platinum-based chemotherapy for non-metastatic disease or curative-intent platinum chemoradiotherapy + PD-1 inhibitor for locally advanced or recurrent/metastatic disease are eligible if disease progression occurred within <6 months after the last treatment and no subsequent systemic therapy was administered.
Histologically or cytologically confirmed as other pathological types (e.g., squamous cell carcinoma, undifferentiated carcinoma, neuroendocrine carcinoma). Mixed pathological types will be categorized based on the predominant component; only subjects with >70% adenocarcinoma component confirmed by a pathologist may enroll.
History of other malignancies within 3 years prior to enrollment. Exceptions include malignancies cured by local therapy (e.g., basal or squamous cell skin cancer, superficial bladder cancer, in situ cervical or breast cancer).
Systemic anti-cancer therapy (e.g., chemotherapy, radiotherapy, immunotherapy, targeted therapy [<2 weeks for small-molecule agents], biologics) within 3 weeks prior to first dose; palliative local therapy for non-target lesions within 2 weeks.
Prior immunotherapy other than PD-1/PD-L1 inhibitors, including checkpoint inhibitors (anti-CTLA-4, anti-CD47, anti-SIRPα, anti-LAG-3), checkpoint agonists (ICOS, CD40, CD137, GITR, OX40), cell therapies, or biologics targeting tumor immunity.