Real-world application of disitamab vedotin (RC48-ADC) in patients with breast cancer with different HER2 expression levels: efficacy and safety analysis
Menée dans un contexte de vie réelle à partir de données portant sur 89 patientes atteintes d'un cancer du sein, cette étude de cohorte rétrospective évalue l'efficacité, du point de vue de la survie sans progression, et la toxicité du disitamab védotin (un conjugué anticorps-médicament ciblant HER2) en fonction du niveau d'expression tumorale de la protéine HER2
Résumé en anglais
Background: Disitamab vedotin (RC48-ADC), an antibody-drug conjugate (ADC), combines specific antibody disitamab with cytotoxicity monomethyl auristatin E to effectively target the human epidermal growth factor receptor 2 (HER2) protein on tumor cells for precise elimination. Recent studies have demonstrated that RC48-ADC offers therapeutic benefits for patients with HER2-positive and HER2-low-expression breast cancer (BC). However, a thorough exploration of its efficacy and safety in real-world settings for patients with metastatic breast cancer (mBC) is currently lacking.
Methods: This retrospective, multicenter, real-world study included patients with mBC who received RC48-ADC from September 2021 to March 2024. These patients include HER2-positive BC and HER2-low-expression BC. The primary endpoint was progression-free survival (PFS). Secondary endpoints included overall survival (OS), restricted mean survival time, objective response rate (ORR), and disease control rate (DCR). Factors affecting efficacy and the occurrence of treatment-related adverse events (TRAE) were evaluated.
Results: The study included a cohort of 89 patients with mBC, with 48 of those being identified as HER2-positive. As of March 2024, 22 deaths were recorded, with an immature median OS. Total PFS varied from 1.0 to 31.2 months, with a median of 5.5 months (95% CI, 4.368-6.632). HER2-positive patients exhibited prolonged PFS compared with HER2-low-expression patients (6.6 months vs 4.1 months, P = .023). The overall ORR stood at 25.8% (95% CI, 0.178-0.358), with higher rates observed in HER2-positive patients compared with HER2-low-expression patients (31.3% vs 19.5%). Similarly, the overall DCR was 78.7% (95% CI, 0.691-0.859), with HER2-positive patients demonstrating superior DCR compared with HER2-low-expression patients (83.3% vs 73.2%). Notably, HER2 expression emerged as the primary determinant of RC48-ADC efficacy. The most prevalent TRAE among all patients included leukopenia (21.3%) and alopecia (20.2%).
Conclusion: RC48-ADC showcases promising efficacy and manageable safety in patients with both HER2-positive and HER2-low-expression mBC.
