Disitamab vedotin is a novel targeted therapeutic agent whose active ingredient is anti-HER2 antibody. It acts by disrupting the internal structural support of cancer cells, inhibiting cancer cell division and inducing programmed cell death. It is mainly used for the treatment of metastatic gastric cancer and urothelial carcinoma.
1. Active Ingredient
Anti-HER2 antibody
2. Indications
This product is indicated for patients with advanced or metastatic cancers with overexpression of HER2 protein (immunohistochemistry [IHC] score 2+ or 3+), specifically:
Patients with advanced or metastatic gastric cancer who have received at least two prior lines of chemotherapy;
Patients with advanced or metastatic urothelial carcinoma who have received prior platinum-based chemotherapy.
3. Patient Population Considerations
Contraindications
Contraindicated in patients with known hypersensitivity to any component of this product.
Use with Caution
Pregnant and lactating women may use this product only under continuous medical monitoring. Discontinue the drug immediately and seek medical attention if any abnormalities occur.
Use in Special Populations
Pregnancy: This drug carries a risk of fetal teratogenicity. A personalized treatment regimen shall be formulated only after a strict assessment of the necessity of treatment by a physician.
Lactation: Breastfeeding is recommended to be suspended during treatment. Alternatively, the physician shall evaluate and select an appropriate regimen between discontinuation of breastfeeding and discontinuation of the drug.
Pediatric use (adolescents under 18 years): Insufficient safety and efficacy data are available; use is not recommended.
Geriatric use: The efficacy and safety profile is generally consistent with that in other adult populations; no special dosage adjustment is required.
4. Drug Interactions
Concomitant use with strong CYP3A4 inhibitors (e.g., certain antibiotics, antifungals)
may increase plasma concentrations of this product, requiring close monitoring.
Concomitant use with strong CYP3A4 inducers (e.g., rifampicin, carbamazepine)
may significantly reduce plasma concentrations of this product and compromise therapeutic efficacy, requiring caution.
Concomitant use with drugs metabolized by CYP3A4 (e.g., certain antihypertensives, antiepileptics)
no obvious interactions have been identified to date, but close monitoring is still required.
5. Dosage Forms and Strengths
Injection, 60 mg per vial.
6. Dosage and Administration
Route of administration
Intravenous infusion. Preparation and dilution must be performed by professional healthcare providers under strict aseptic conditions. Patients must use this product under medical supervision; self-adjustment of the treatment regimen is prohibited.
Recommended dosage
Gastric cancer: 2.5 mg/kg body weight once every two weeks, continued until disease progression or intolerable adverse reactions occur.
Urothelial carcinoma: 2.0 mg/kg body weight once every two weeks, continued until disease progression or severe adverse reactions occur.
7. Patient Selection, Reconstitution and Dilution
Patient Selection
Patients treated with this product must undergo HER2 protein expression testing in an accredited laboratory, with an IHC score of 2+ or 3+. Testing methods and result interpretation shall follow the instructions for use of the companion diagnostic reagent.
Reconstitution
Slowly inject 6 mL of sterile water for injection into a 60 mg vial using a sterile syringe.
Gently rotate the vial until the drug is completely dissolved; vigorous shaking is prohibited.
Reconstitution must be completed within 10 minutes. The reconstituted solution is colorless to pale yellow and clear.
Use the reconstituted solution immediately. Unused solution may be stored refrigerated at 2°C–8°C for no more than 24 hours.
Inspect the solution before use; discard if cloudy, discolored, or containing particulate matter.
Dilution
Calculate the required volume based on the patient’s body weight and withdraw the corresponding amount of reconstituted solution.
Add the solution to a 250 mL infusion bag of 0.9% Sodium Chloride Injection or 5% Dextrose Injection.
Use a dedicated infusion set equipped with a 0.2/0.22 micron filter.
The diluted infusion solution must be used within 6 hours at room temperature, or within 24 hours if refrigerated (2°C–8°C). Allow to equilibrate to room temperature before use.
Discard any unused portion immediately; reuse is prohibited.
Administration and Handling
For intravenous infusion only; intravenous bolus or rapid injection is prohibited.
Infusion duration: 30–90 minutes per dose, with a standard recommendation of 60 minutes.
If hypersensitivity or infusion-related reactions occur during infusion, immediately reduce the infusion rate or interrupt administration, and institute necessary medical measures.
Discontinue administration immediately in the event of life‑threatening severe reactions.
8. Dose Modification
Dosage should be adjusted according to individual patient tolerance. Dose reduction should follow the criteria below in the event of adverse reactions; treatment should be discontinued if symptoms worsen continuously.
Gastric cancer patients
First dose reduction to 2.0 mg/kg; second dose reduction to 1.5 mg/kg.
Urothelial carcinoma patients
First dose reduction to 1.5 mg/kg; second dose reduction to 1.0 mg/kg.
Note: If there are discrepancies between the prescribing information of different manufacturers, consult the attending physician or a qualified pharmacist immediately.
9. Important Instructions Prior to Administration
Use is absolutely prohibited in patients with hypersensitivity to this product.
Patients receiving other medications must inform their physician or pharmacist of all concomitant medications, existing medical conditions, and current treatment regimens before initiating therapy with this product.
Patients who are pregnant, planning a pregnancy, or breastfeeding must truthfully inform their physician in advance for a personalized treatment plan.
Use in pregnant and lactating women is generally not recommended, except when judged strictly necessary by a physician, under close monitoring.
10. Important Instructions Following Administration
Storage and transportation
Store and transport refrigerated at 2°C–8°C, protected from light. Shelf life: 24 months.
Post‑treatment monitoring
Strictly follow medical advice, closely monitor bodily reactions, and consult a physician promptly if discomfort occurs; do not discontinue treatment without medical advice.
Dietary advice
Maintain a light diet during treatment; avoid spicy and irritating foods such as chili and Sichuan pepper.
Product inspection
Discontinue use immediately if the drug shows darkening, changes in appearance, or abnormal odor, indicating potential degradation.
Pediatric safety: Keep this product out of the reach of children.
11. Management of Overdosage
In case of overdosage, observe the patient immediately for abnormalities such as dyspnea and tachycardia, and promptly contact a physician. Administer targeted treatment based on specific symptoms (e.g., intravenous fluids to enhance drug elimination, oxygen supplementation to maintain respiration) and continuously monitor vital signs including blood pressure and heart rate.
12. Adverse Reactions
Adverse reactions of this product are related to individual constitution and administration route, classified by frequency and severity below. Close monitoring for changes in physical condition is required during treatment; seek medical attention promptly if discomfort occurs.
Common reactions
Headache, dizziness, gastrointestinal discomfort, arthralgia, insomnia, burning sensation on urination, etc.
Mild reactions
Nausea, vomiting, constipation, diarrhea, decreased appetite, etc.
Uncommon reactions
Pneumonia, decreased cardiac function, chills and rigors, sore throat, etc.
Severe reactions (requiring immediate intervention): Hypersensitivity reactions, which may cause severe allergic symptoms including rash, dyspnea, and even shock.
Note: Immediate medical contact is required for symptoms such as chest distress and dyspnea. Continuous monitoring with devices such as a sphygmomanometer and electrocardiogram may be necessary.
13. Discontinuation Criteria
Treatment must be discontinued immediately and medical attention sought if any of the following occur. The physician will determine whether permanent discontinuation is required, or whether treatment may continue with dose adjustment or alternative therapy.
Abnormal blood test results, e.g., significant fluctuations in white blood cell count;
Abnormal sensations such as numbness and tingling in the hands and feet;
Abnormal hepatic function indicators, e.g., elevated transaminases;
Other severe adverse reactions that significantly affect daily life.
Note: Consult a physician promptly even for mild discomfort; do not discontinue treatment without medical advice.
