A multi-centre, phase 1a/1b dose escalation and expansion study of the HER2-directed antibody–drug conjugate T-Bren (BL-M07D1) in advanced breast cancer and other solid tumours
Mené sur 253 patientes atteintes d'un cancer du sein de stade localement avancé ou métastatique ou d'une autre tumeur solide, cet essai de phase IA/B détermine la dose maximale tolérée du trastuzumab brengitécan (un conjugué anticorps-médicament ciblant HER2) et évalue son efficacité du point de vue du taux de réponse globale
Background: Trastuzumab brengitecan (T-Bren; BL-M07D1) is a HER2-directed antibody-drug conjugate (ADC) comprising a monoclonal antibody, a cathepsin B–cleavable linker, and a potent topoisomerase I inhibitor payload (Ed-04). We aimed to evaluate the safety, tolerability, pharmacokinetics, and preliminary antitumour activity of T-Bren in patients with advanced breast cancer and other solid tumours.
Methods: This phase 1 dose escalation and expansion study enrolled patients with inoperable locally advanced or metastatic breast cancer or other solid tumours pretreated with systemic therapy. Patients received intravenous T-Bren at doses ranging from 1.0 mg/kg on days 1 and 8 every 3 weeks (D1D8 Q3W) (accelerated titration), to 2.6 mg/kg, 3.2 mg/kg, 3.8 mg/kg, 4.4 mg/kg, 5.0 mg/kg, 5.6 mg/kg, 6.2 mg/kg on day 1 every 3 weeks (D1Q3W) (i3+3 design). Primary objectives were to assess dose-limiting toxicity/maximum tolerated dose (DLT/MTD), and establish the recommended phase 2 dose (RP2D).
Findings: Overall, 253 patients were treated: DLTs occurred in two patients treated at 6.2 mg/kg Q3W, including grade 4 neutropenia with myelosuppression and grade 3 thrombocytopaenia in one patient, and grade 4 febrile neutropenia in another. In patients with breast cancer, ORR was 81.5% (66/81) in HER2-positive subgroup, 69.5% (57/82) in hormone receptor–positive/HER2-low disease, and 58.3% (14/24) in hormone receptor–negative/HER2-low disease. Median PFS was 18.2 months, 14.0 months, and 7.2 months in the HER2-positive, HR-positive/HER2-negative, and HR-negative/HER2-negative subgroups, respectively.
Interpretation: T-Bren demonstrated a manageable safety profile and clinically meaningful antitumour activity across a broad spectrum of HER2 expression in advanced breast cancer. The 4.4 mg/kg every three weeks regimen was established as the RP2D in breast cancer.
eBioMedicine , résumé, 2026