shr-a1811 for subjects with her2-positive gastric cancer and gastroesophageal junction adenocarcinoma after progression on or after first-line anti-her2 therapy-containing regimen

Conditions: HER2-positive Advanced Gastric Cancer or Gastroesophageal Junction Adenocarcinoma

Summary: this study will assess the efficacy and safety of shr-a1811 compared with treatment chosen by the investigator in participants with her2-positive (defined as immunohistochemistry \[ihc\] 3+ or ihc 2+/in situ hybridization \[ish\]+) gastric or gej adenocarcinoma (based on \[american society of clinical oncology (asco) college of american pathologists (cap) guidelines who have progressed on or after a first-line anti-her2 therapy-containing regimen.


Eligibility criteria:
inclusion criteria: 1. age 18-75 years old, male and female; 2. histologically or cytologically confirmed gastric or gastroesophageal junction adenocarcinoma, and unresectable locally advanced or metastatic disease 3. prior anti-her-2 containing treatment 4. progression on or after first-line standard treatment (prior neoadjuvant or adjuvant therapy can be counted as a line of therapy if the subject progressed on or within 6 months of completing neoadjuvant or adjuvant therapy); 5. centrally confirmed her2-positive (ihc 3+ or ihc 2+ and evidence of her2 amplification by ish) as classified by asco-cap on a tumor biopsy 6. at least one measurable lesion according to the solid tumor response evaluation criteria (recist 1.1); 7. ecog: 0-1; 8. expected survival ≥12 weeks; 9. good blood reserve and liver, kidney and coagulation function; 10. willing to provide informed consent for study participation. exclusion criteria: 1. receive the last dose of anti-cancer therapy(including chemotherapy, radiotherapy, biological therapy, targeted therapy or immunotherapy) within 4 weeks, prior to the first dose; 2. known allergies to monoclonal antibodies and inactive ingredients of this product, and allergies to paclitaxel, docetaxel, and irinotecan concurrently; 3. the toxicity of prior anti-tumor therapy did not recover to the level specified by ctcae v5.0 grade evaluation ≤ grade 1 or inclusion/exclusion criteria; 4. clinically active central nervous system metastases; 5. uncontrollable pleural effusion, pericardial effusion, or ascites requiring repeated drainage; 6. clinically significant gastrointestinal disorder by the opinion of investigator; 7. has a history of immunodeficiency, including a positive hiv test; 8. during the screening visits and before the first dose, unexplained fever \> 38.5℃, severe infection (ctc-ae \> grade 2), and active pulmonary inflammation were indicated by screening imaging; 9. subjects with interstitial pneumonia or with ≥ grade 3 interstitial pneumonia during prior treatment with immune checkpoint inhibitors; 10. active hepatitis b(hbv dna ≥ 500 iu/ml), hepatitis c (positive for hepatitis c antibody, and hcv-rna above the lower limit of detection of the analytical method); 11. clinically significant cardiovascular disease ,such as severe/unstable angina, symptomatic congestive heart failure (nyha ≥ class ii.), clinically significant supraventricular or ventricular arrhythmia requiring treatment or intervention, myocardial infarction within 6 months before the first dose, cerebrovascular accident (including transient ischemic attack); qtcf of 12-lead ecg was ≥470 ms; left ventricular ejection fraction \<50%; clinically uncontrolled hypertension; 12. had other malignancies with 5 years; 13. pregnant or lactating women; 14. other factors that might have led to drop out the study by the investigator opinion.