How often should gosatuzumab (Todavi) be administered?

Gosatuzumab (Trodelvy, generic name: Sacituzumab Govitecan) is an antibody drug conjugate (ADC), mainly used to treat metastatic triple-negative breast cancer (mTNBC) and advanced urothelial cancer (mUC) that have failed platinum-based chemotherapy. The drug consists of a monoclonal antibody targeting Trop-2 and a topoisomerase I inhibitor SN -38Coupled through a hydrolyzable linker, it can specifically bind to the Trop-2 antigen on the surface of tumor cells, release cytotoxic drugs, and inhibit tumor growth.

Frequency and dose of administration

The standard dosing regimen of gosatuzumab usually follows a cycle of 28 days (i.e. every 4 weeks is a treatment cycle), and the recommended dose is 10 mg/kg by intravenous infusion. Dosage on day 1 and day 8, repeated every 21 days. This dosing regimen is suitable for most patients in the approved indications, including metastatic triple-negative breast cancer and urothelial cancer. The specific dosing frequency is as follows:

1.Day 1 (Day 1): Calculate the dose based on body weight (10 mg/kg), intravenous infusion.

2.Day 8 (Day 8): Intravenous infusion at the same dose (10 mg/kg) again.

3.Day 15 to Day 21 (Day 15–21): Rest, no medication.

4.Enter the next 28 day cycle (if the patient tolerates it well) and repeat the above dosing pattern.

The design of this dosing frequency takes into account the pharmacokinetic properties of the drug and patient tolerance, allowing the active ingredients to be continuously released within the tumor cells while reducing the risk of adverse reactions caused by dose accumulation.

Dosage methods and precautions

Gosatuzumab must be administered by intravenous infusion . The recommended infusion method is as follows:

1.First infusion: usually takes 3 hours at a slower rate to reduce infusion-related adverse reactions (such as infusion reactions, nausea, or hypotension).

2.Subsequent infusion: If the patient tolerates the first infusion well, the infusion can be completed within1 to 2 hours.

3.Precautions: Because gosatuzumab may cause infusion reactions, doctors usually use anti-allergic drugs (such asH1 receptor antagonists) and antipyretic analgesics before infusion to reduce the risk. Additional corticosteroids may be needed in patients with previous infusion reactions.

In addition, rapid bolus or intravenous bolus injection should be avoided during the infusion of gosatuzumab to reduce the risk of adverse reactions. At the same time, the drug cannot be mixed with other drugs. It must be diluted with 0.9% sodium chloride injection, and stored at room temperature or refrigerated conditions before use within a short period of time to maintain stable drug efficacy.

Dosage adjustments and special circumstances

Although the recommended standard dose is 10 mg/kg (D1, D8), dose adjustment or dosing frequency may need to be adjusted if:

1.Dose reduction

Grade 1 reduction: from 10 mg/kg to 7.5 mg/kg.

Level 2 reduction: If intolerable side effects still occur, further reduce to 5 mg/kg.

Grade 3 reduction: If the patient cannot tolerate 5 u200bu200bmg/kg, the drug should be permanently discontinued.

2.Severe bone marrow suppression (neutropenia or thrombocytopenia)

If Absolute neutrophil count (ANC) < 1,500/μL or platelets < 100,000/μL, administration should be delayed until blood counts return to acceptable levels.

If Grade 3 or Grade 4 neutropenia occurs (ANC < 1,000/μL), consider using Granulocyte colony-stimulating factor (G-CSF) and reduce the dose upon recovery.

3.Gastrointestinal adverse reactions (nausea, vomiting, diarrhea)

For severe nausea or vomiting, it is recommended to use 5-HT3 receptor antagonists (such as ondansetron) or NK-1 receptor antagonists (such as aprepitant) for prevention.

If the patient develops persistent diarrhea (especially Grade 4 diarrhea), loperamide (Loperamide) needs to be used to control the symptoms, and the dose should be appropriately reduced or the medication should be suspended.

4. Impairment of liver or kidney function

Mild or moderate Hepatic impairment Patients with mild or moderate hepatic impairment may be dosed as usual but should be closely monitored.

Severe Patients with liver function impairment (Child-Pugh C) are not recommended to use this drug.

Use with caution in patients with renal insufficiency (creatinine clearance<30 mL/min) as clinical data are limited.

The standard dosing frequency for gosatuzumab (Trodelvy) is 28One cycle, intravenous infusion on day 1 and day 8, repeated once on day 21. The recommended dose is 10 mg/kg. The drug must be administered as a slow intravenous infusion and the dose adjusted according to the patient's tolerance. For patients who develop bone marrow suppression, gastrointestinal discomfort, or abnormal liver and kidney function, appropriate dose reduction or dosing delay may be required. During the treatment process, doctors usually monitor the patient's blood routine and other physiological indicators regularly to ensure efficacy and safety. Patients should pay close attention to their adverse reactions during treatment and communicate with their doctors in a timely manner to adjust the plan.

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Reference materials:https://www.trodelvy.com/