Formulation and specifications: Lyophilized formulation: 60 mg/stem
Indications: Patients with HER2 overexpression in locally advanced or metastatic gastric cancer (including gastroesophageal junction adenocarcinoma) who have received at least 2 systemic chemotherapies. HER2 overexpression is defined as a HER2 immunohistochemical result of 2+ or 3+, regardless of FiSH/CiSH amplification.
Rational dosing points:
1. HER2 testing should be performed prior to treatment with this product, and the relevant tests should be performed using assays approved by the State Drug Administration.
2. The recommended dose is 2.5 mg/kg once every two weeks by intravenous drip over 30-90 minutes (about 60 minutes is usually recommended).
3. This indication was granted conditional approval based on the results of a phase II single-arm clinical trial in patients with locally advanced or metastatic gastric cancer (including adenocarcinoma of the gastroesophageal junction) with HER2 overexpression.
4. Common laboratory test-based adverse reactions include abnormal hematology and elevated transaminases. Common clinical signs and symptoms of adverse reactions include hair loss, fatigue, and hypoesthesia.
5. If a patient experiences a drug-related grade ≥3 hematologic abnormality, it is recommended that treatment be suspended, symptomatic treatment be instituted, and twice-weekly hematologic testing be performed until recovery to CTCAE ≤1 or pre-initiation levels, and that the dose be adjusted if adverse reactions occur again after resumption of drug administration. If the patient does not return to CTCAE ≤ grade 1 or pre-initiation levels after 28 days of drug suspension, discontinuation of therapy is recommended.
6. If a patient develops a drug-related grade ≥3 transaminase elevation, it is recommended that treatment be suspended, symptomatic treatment be instituted, and twice-weekly blood biochemistry be performed until recovery to CTCAE ≤1 or pre-initiation levels, and that the dose be adjusted if adverse reactions occur again after resumption of drug administration. If the patient does not return to CTCAE ≤ grade 1 or pre-initiation levels after 28 days of drug suspension, discontinuation of therapy is recommended.
7. If the patient develops drug-related sensory abnormalities (e.g., numbness, etc.) and does not recover to a level that would allow continued dosing after 28 days of drug suspension, discontinuation of therapy is recommended.
8. No dose adjustment is required for patients with mild hepatic impairment. The effect of moderate to severe hepatic impairment on the pharmacokinetics of this product has not been examined. No dose adjustment is required in patients with mild to moderate renal impairment. The pharmacokinetics in patients with severe renal impairment have not been evaluated, and no data are available from studies in patients with severe renal impairment.
9. The safety and efficacy of this product in children and adolescents under 18 years of age have not been established. No significant differences in efficacy and safety have been observed in clinical trials in patients ≥65 years of age compared to the overall population.