The NeoSTAR study investigated the combination of sacituzumab govitecan, a TROP-2–directed antibody–drug conjugate, and pembrolizumab, an anti–programmed death-ligand 1 monoclonal antibody, as neoadjuvant therapy for early-stage triple-negative breast cancer (TNBC). Fifty patients with stage II to III TNBC were enrolled and received 4 cycles of sacituzumab govitecan at a starting dose of 10 mg/kg on days 1 and 8, and pembrolizumab 200 mg on day 1 of a 21-day cycle before surgery. Patients with residual disease could receive additional neoadjuvant chemotherapy at the discretion of their physician.

Pathologic complete response (pCR) was achieved in 32% of patients treated with sacituzumab govitecan/pembrolizumab (95% confidence interval [CI], 19.5-46.7). Event-free survival after 18 months was 90.6% (95% CI, 89.2-100.0). The proportion of patients who showed radiographic response was 66% (30% complete response, 36% partial response). Among patients with pathogenic BRCA mutations, 60% (95% CI, 14.7-94.7) achieved pCR with sacituzumab govitecan/pembrolizumab alone.

Grade ≥3 adverse events (AEs) occurred in 40% of patients. Common AEs included nausea (56%), alopecia (52%), fatigue (46%), and diarrhea (44%). The number of patients experiencing treatment discontinuation (10%) or dose reductions (8%) was minimal. This first trial evaluating sacituzumab govitecan/pembrolizumab in early-stage TNBC demonstrated promising clinical activity, with a 32% pCR rate after sacituzumab govitecan/pembrolizumab alone. The regimen was generally tolerable, with manageable toxicity. Further research is necessary to optimize the duration and sequence of sacituzumab govitecan/pembrolizumab and chemotherapy in this patient population.

Source: Abelman R, et al. A phase 2 study of response-guided neoadjuvant sacituzumab govitecan and pembrolizumab (SG/P) in patients with early-stage triple-negative breast cancer: results from the NeoSTAR trial. Presented at: 2025 ASCO Annual Meeting. May 30-June 3, 2025; Chicago, IL. Abstract 511.