The treatment landscape for metastatic triple-negative breast cancer (TNBC) continues to evolve. On June 24, 2026, the U.S. Food and Drug Administration (FDA) approved sacituzumab govitecan (Trodelvy) for two new first-line indications, expanding its role from later-line therapy to the frontline setting.
Based on the phase 3 ASCENT-03 and ASCENT-04/KEYNOTE-D19 trials, sacituzumab govitecan is now approved:
- As monotherapy for patients with unresectable locally advanced or metastatic TNBC who are not candidates for PD-1/PD-L1 inhibitors.
- In combination with pembrolizumab for patients with PD-L1-positive disease (CPS ≥10).
These approvals establish new first-line treatment options for two distinct patient populations.
Sacituzumab govitecan (Trodelvy)
Why Is This Approval Important?
Triple-negative breast cancer accounts for approximately 15–20% of breast cancers and remains one of the most aggressive subtypes. Although immune checkpoint inhibitors have improved outcomes in PD-L1-positive disease, many patients either do not express PD-L1 or are not candidates for immunotherapy. Until now, chemotherapy remained the primary first-line option for these patients.
Sacituzumab govitecan is a Trop-2-directed antibody-drug conjugate (ADC) that delivers the topoisomerase I inhibitor SN-38 directly to tumor cells while also producing a bystander effect that may enhance antitumor activity. Its success in previously treated metastatic TNBC raised the question of whether earlier use could further improve patient outcomes.
ASCENT-03: Replacing Chemotherapy in PD-1–Ineligible Patients
ASCENT-03 enrolled 558 patients with previously untreated unresectable locally advanced or metastatic TNBC who were not candidates for PD-1/PD-L1 inhibitor therapy. Patients received either sacituzumab govitecan or physician’s choice chemotherapy.
Key Results
- Median PFS: 9.7 vs 6.9 months
- HR: 0.62 (95% CI 0.50–0.77; P<0.0001)
- ORR: 50% vs 47%
Although objective response rates were similar, responses with sacituzumab govitecan were substantially more durable, resulting in a significant improvement in progression-free survival.
ASCENT-04/KEYNOTE-D19: Combining ADC Therapy With Immunotherapy
For patients with PD-L1-positive (CPS ≥10) metastatic TNBC, pembrolizumab plus chemotherapy has become a standard first-line approach. ASCENT-04 investigated whether replacing chemotherapy with sacituzumab govitecan could further improve outcomes while maintaining pembrolizumab.
The study enrolled 443 patients, comparing sacituzumab govitecan plus pembrolizumab with chemotherapy plus pembrolizumab.
Key Results
- Median PFS: 11.2 vs 7.8 months
- HR: 0.65 (95% CI 0.51–0.84; P=0.0009)
- ORR: 61% vs 55%
Overall survival data remain immature.
Safety
No unexpected safety signals were identified. The toxicity profile was consistent with previous experience using sacituzumab govitecan.
The most important adverse events include:
- Neutropenia
- Diarrhea
- Nausea and vomiting
- Infusion-related reactions
Immune-related adverse events remain those expected with pembrolizumab.
What Does This Mean for Clinical Practice?
These approvals further reinforce the movement of antibody-drug conjugates into earlier lines of treatment.
The FDA now recognizes two distinct first-line strategies:
- PD-L1-negative or PD-1–ineligible disease: Sacituzumab govitecan monotherapy.
- PD-L1-positive disease (CPS ≥10): Sacituzumab govitecan plus pembrolizumab.
Rather than simply replacing chemotherapy, these approvals introduce ADC-based therapy as a new frontline platform for metastatic TNBC, reflecting the growing role of targeted drug delivery in breast cancer treatment.
Take-Home Message
The FDA approval of sacituzumab govitecan in both PD-L1-positive and PD-L1–ineligible metastatic TNBC marks one of the most important practice-changing advances in breast cancer this year. By moving a highly active Trop-2 antibody-drug conjugate into the first-line setting, the ASCENT-03 and ASCENT-04 trials establish new standards of care that may reduce reliance on conventional chemotherapy and further integrate ADCs into frontline treatment strategies.