How Trodelvy Targets Breast Cancer Cells
Trodelvy (sacituzumab govitecan) treats certain breast cancers by delivering chemotherapy directly to tumor cells. It combines a monoclonal antibody that binds to Trop-2—a protein overexpressed on many breast cancer cells—with SN-38, the active form of irinotecan chemotherapy.[1] Once bound, the antibody pulls the drug inside the cell, where SN-38 damages DNA and triggers cell death. This approach limits exposure to healthy tissues compared to traditional chemo.[2]
Which Breast Cancers Does It Treat?
Trodelvy is FDA-approved for unresectable locally advanced or metastatic triple-negative breast cancer (TNBC) in adults who received at least two prior therapies, including a taxane and an anthracycline.[1] It showed efficacy in the ASCENT trial, where it extended median progression-free survival to 5.6 months versus 1.7 months with standard chemo, and overall survival to 12.1 months versus 6.7 months.[3]
How Is Trodelvy Administered?
Patients receive Trodelvy intravenously on days 1 and 8 of a 21-day cycle: 10 mg/kg for the first two cycles, then 10 mg/kg if tolerated.[1] Treatment continues until disease progression or unacceptable toxicity. Premedication with antihistamines, acetaminophen, and steroids reduces infusion reactions.
Common Side Effects and Management
Neutropenia (62%), diarrhea (64%), and nausea (64%) are frequent; severe cases include febrile neutropenia (6%) and infections.[1] Dose reductions occur in about 25% of patients. Monitoring blood counts and hydration helps manage these. Unlike antibody-drug conjugates targeting HER2, Trodelvy's Trop-2 focus suits TNBC lacking those markers.
How Does It Compare to Other TNBC Treatments?
| Treatment | Mechanism | Key Trial PFS (months) | OS Benefit |
|-----------|-----------|-------------------------|------------|
| Trodelvy | Trop-2 + topoisomerase inhibitor | 5.6[3] | Yes (HR 0.48) |
| Capecitabine | Oral chemo | 1.7 (ASCENT control)[3] | No |
| Eribulin | Microtubule inhibitor | ~2.6 (prior studies) | Modest |
| Sacituzumab tirumotecan (experimental) | Similar Trop-2 ADC | Ongoing trials | N/A |
Trodelvy outperforms single-agent chemo in pretreated TNBC but lacks head-to-head data with immunotherapy combos like pembrolizumab plus chemo.[4]
Ongoing Approvals and Research
Beyond TNBC, Trodelvy gained approval for HR+/HER2- metastatic breast cancer post-endocrine and CDK4/6 inhibitor therapy (TROPiCS-02 trial: PFS 5.5 vs. 4.0 months).[5] Trials explore earlier lines, combinations with PARP inhibitors, and other cancers like urothelial.
Sources
[1]: Trodelvy Prescribing Information (FDA)
[2]: Gilead Sciences Mechanism Overview
[3]: ASCENT Trial (NEJM 2021)
[4]: KEYNOTE-355 Trial Summary
[5]: TROPiCS-02 Results (NEJM 2023)