Managing Side Effects of SG

From a pharmacologic standpoint, the adverse events associated with sacituzumab govitecan (SG)—particularly neutropenia and diarrhea—are consistent with the mechanism of its payload. SG delivers SN-38, the active metabolite of irinotecan, a topoisomerase I inhibitor known for dose-limiting gastrointestinal and hematologic toxicities. Because SN-38 affects rapidly dividing cells, bone marrow suppression leading to neutropenia is an anticipated effect. Similarly, SN-38 exposure within the gastrointestinal epithelium contributes to diarrhea, a well-recognized toxicity of irinotecan-based therapies. Although SG is designed to target Trop-2–expressing tumor cells, some degree of systemic and off-tumor exposure occurs, accounting for these predictable adverse reactions.