Sacituzumab Govitecan: Trop-2 Targeted ADC Clinical Medication Guide

　　Sacituzumab Govitecan is a Trop-2 targeted Antibody-Drug Conjugate(ADC),composed of a humanized anti-Trop-2 monoclonal antibody conjugated to SN-38(the active metabolite of irinotecan,a topoisomerase I inhibitor)via a specific cleavable linker.As one of the first Trop-2 targeted ADCs approved for marketing worldwide,it provides a novel therapeutic option for patients with advanced solid tumors.

　　Basic Pharmaceutical Profile and Market Information

　　Sacituzumab Govitecan has been approved for marketing in multiple countries and regions globally.The overseas market price is approximately 2000 to 3000 US dollars per pack,and there are currently no approved generic versions available on the market.

　　Core Anti-Tumor Mechanism of Action

　　Sacituzumab Govitecan exerts its anti-tumor effect through the synergy of precise targeting and potent cytotoxicity,with the core mechanism as follows:

　　The anti-Trop-2 monoclonal antibody moiety of the drug specifically recognizes and binds to the Trop-2 protein highly expressed on the surface of tumor cells;

　　After antigen-antibody binding,the drug is internalized into the tumor cells via endocytosis;

　　In the lysosomal environment within tumor cells,the linker is cleaved to site-specifically release the cytotoxic payload SN-38;

　　SN-38,a potent topoisomerase I inhibitor,blocks DNA replication and transcription of tumor cells,thereby inducing tumor cell apoptosis;

　　The drug exerts a robust"bystander effect",which can penetrate cell membranes to kill adjacent tumor cells,further expanding the anti-tumor efficacy.

　　Trop-2 is highly expressed in a variety of epithelial-derived tumor cells,while its expression level is extremely low in normal human tissues.This feature endows the drug with favorable tumor targeting selectivity,which can enhance anti-tumor efficacy while reducing damage to normal tissues.

　　Approved Clinical Indications

　　The core approved indications of Sacituzumab Govitecan include:

　　Unresectable locally advanced or metastatic triple-negative breast cancer(mTNBC)in patients who have received at least 2 prior lines of systemic therapy;

　　Locally advanced or metastatic urothelial carcinoma(UC).

　　In addition,clinical trials of the drug in multiple other solid tumors are ongoing.Prior to clinical administration,positive Trop-2 expression in tumor tissue must be confirmed via immunohistochemistry(IHC)testing before standardized use.

　　Standard Dosage and Administration

　　The standard dosing regimen of Sacituzumab Govitecan is based on a 21-day treatment cycle,with the core administration specifications as follows:

　　The recommended dose is 10 mg/kg,administered via intravenous infusion;

　　The duration of the first infusion should be no less than 3 hours,with close monitoring of the patient's tolerance during the infusion;

　　If the patient tolerates the first infusion well,the infusion duration for subsequent cycles can be shortened to 1 to 2 hours;

　　Treatment should be continued until disease progression or unacceptable toxicity occurs.

　　For clinical administration,the precise dose should be calculated according to the patient's actual body weight,and the dosing regimen should be adjusted in a timely and standardized manner based on the adverse events occurring during the treatment period.

　　Standard Pre-Infusion Preparation

　　To ensure medication safety,the following standardized preparations must be completed before each infusion:

　　Inquire about the patient's previous history of drug allergy in detail;patients with a history of allergy should receive standardized antihistamine premedication in advance;

　　Complete standardized pre-infusion premedication:administer acetaminophen,H2 receptor antagonist,and corticosteroid 30 to 60 minutes before dosing to reduce the risk of infusion-related reactions;

　　Confirm that the patient's hematological indicators meet the medication criteria:platelet count≥75×10⁹/L,absolute neutrophil count≥1.0×10⁹/L;

　　Prepare first-aid equipment and related rescue medications for anaphylactic reactions in advance to handle sudden infusion-related adverse events;

　　Fully fulfill the obligation of informed consent,explain the potential benefits and related risks of the medication to the patient and their family in detail,and sign the informed consent document.

　　Common Adverse Events and Clinical Management

　　The adverse events of Sacituzumab Govitecan during treatment are mainly hematological and gastrointestinal reactions,most of which can be effectively controlled through standardized intervention.The core adverse events and corresponding management protocols are as follows:

　　Myelosuppression:Neutropenia is the most common adverse event of the drug,with an incidence rate of approximately 60%-70%.Routine blood count monitoring is required during treatment,and granulocyte colony-stimulating factor(G-CSF)should be administered for supportive treatment when necessary.For grade 3-4 neutropenia,dosing should be suspended promptly,and the dose should be adjusted in a standardized manner after the indicators recover.

　　Gastrointestinal Reactions:The incidence of nausea,vomiting and diarrhea is approximately 50%-60%.Prophylactic antiemetics can be administered clinically to reduce the risk of vomiting.In case of diarrhea,loperamide should be administered promptly for symptomatic treatment,and patients should be guided to supplement water and electrolytes to avoid dehydration.

　　Alopecia:The incidence rate is approximately 30%-40%,mostly grade 1-2 mild to moderate reactions.No specific drug intervention is required,and hair can gradually recover spontaneously after drug withdrawal.Scalp cooling caps can be used during treatment to reduce the incidence of alopecia.

　　Fatigue:The incidence rate is approximately 30%-40%,mainly mild to moderate.Patients should be guided to rest reasonably and preserve physical strength,and symptomatic supportive treatment should be given according to the degree of fatigue.

　　Rash:The incidence rate is approximately 20%-30%,mainly acneiform rash.Patients should be guided to keep the skin clean,topical corticosteroid ointment can be used to relieve symptoms,and oral antibiotics can be administered for standardized treatment when symptoms are severe.