Long-acting G-CSF empegfilgrastim with dose-dense chemotherapy for patients with stage II–III TNBC: Defendor Special trial, primary analysis

Triple-negative breast cancer (TNBC) remains one of the most aggressive subtypes of breast cancer, associated with a high risk of early recurrence and limited systemic treatment options. Despite advances in neoadjuvant therapy, including platinum-based agents and immune checkpoint inhibitors, the widespread adoption of these approaches is limited by their toxicity, cost, and insufficient data on their combination with dose-dense regimens. Study objective. To evaluate the efficacy and safety of empegfilgrastim (a long-acting granulocyte colony-stimulating factor, G-CSF) in maintaining dose intensity during dose-dense neoadjuvant therapy (NAT) in patients with stage II–III triple-negative breast cancer (TNBC). Materials and methods. This prospective study enrolled 60 patients who received dose-dense chemotherapy with the ddAC regimen (doxorubicin + cyclophosphamide every 14 days) followed by weekly paclitaxel and carboplatin. Empegfilgrastim was administered once after each ddAC cycle. The primary endpoint was achieving a relative dose intensity (RDI) of ≥ 85 %. Results. The target RDI was achieved in 96 % of patients (median values: 100 % for ddAC and 94 % for weekly paclitaxel and carboplatin). Efficacy. A pathological complete response (pCR) was observed in 50 % of patients with localized (initially operable) disease and 43 % of those with locally advanced (initially inoperable) stages. Low residual tumor burden (RCB 0–1) was noted in 63 % of cases. Safety. The safety profile demonstrated a low incidence of severe adverse events (grade III–IV neutropenia: 1.7 %). Conclusion. Empegfilgrastim effectively maintains high dose intensity in NAT, leading to a significant pCR rate comparable to that of immunotherapy but with a more favorable safety profile.