Ph1b/2 Study of the Safety and Efficacy of SHR-A1811 Combinations in Advanced HER2+ Gastric Cancer

This is an open,multicentre phase Ib/II study. The purpose of phase Ib is to evaluated the safety, tolerability, pharmacokinetics, immunogenicity, and preliminary antitumor activity of SHR-A1811 in combination with chemotherapy and/or immunotherapy in HER2-positive advanced/metastatic gastric/gastroesophageal junction adenocarcinoma patients.The Phase II study was designed to evaluate the efficacy and safety of SHR-A1811 in combination with chemotherapy and/or immunotherapy for advanced/metastatic HER2-positive gastric/gastroesophageal conjunctional adenocarcinoma patients.

Inclusion Criteria:Age from 18 to 75 , Male and female participantsLocal advanced unresectable or metastatic disease Pathologically documented adenocarcinoma of gastric or gastroesophageal junction;HER2 positive;Phase Ib: progression at least one prior Regimen or could not tolerate the standard treatment，pevious anti-HER2 therapy was included Phase II: previously untreated patients ;ECOG 0-1;The expected survival ≥3 months;Sufficient bone marrow and organ functions;Exclusion Criteria:There were ascites, pleural effusion and pericardial effusion that needed to be treated;Major surgery was performed within 4 weeks;Have active autoimmune disease or history of autoimmune disease;Patients with interstitial pneumonia;There was severe infection within 4 weeks before starting the study treatment;Patients with active pulmonary tuberculosis infection history within 1 year before enrollment;Serious cardiovascular and cerebrovascular diseases;Gastrointestinal perforation and/or gastrointestinal fistula occurred within 6 months before enrollment;