Real-World Feasibility, Toxicity, and Early Outcomes of Neoadjuvant Pembrolizumab-Based Systemic Therapy in Early Triple-Negative Breast Cancer: A Single-Centre Chinese Cohort from Hong Kong
Year: 2026
Type: article
Study design: Observational Study
Abstract: Background: Neoadjuvant treatment for early-stage triple-negative breast cancer has been widely used, and the KEYNOTE-522 (KN522) regimen has become a standard of care for early-stage TNBC, with alternative treatment options including a dose-dense anthracycline/taxane-based regimen for patients without access to neoadjuvant immunotherapy. Nevertheless, real-world evidence in Chinese populations, especially high-risk cohorts such as older populations and those with substantial nodal burden, is limited regarding both efficacy and tolerability. This study describes the outcomes associated with neoadjuvant systemic therapy in a Hong Kong Chinese cohort. Objectives: This study aimed to describe the feasibility, treatment delivery, tolerability and safety of the KN522 regimen in stage I-III TNBC in a Chinese cohort in Hong Kong. Another cohort treated with dose-dense neoadjuvant chemotherapy, which is also a standard-of-care treatment alternative, is presented to provide context of local treatment practice. Methods: We conducted a retrospective observational cohort study of 59 patients with stage I-III TNBC who received neoadjuvant systemic treatment prior to breast surgery at a tertiary centre in Hong Kong between February 2022 and June 2025. The primary cohort received the KN522 regimen (n = 30). A contextual reference cohort received dose-dense epirubicin/cyclophosphamide followed by paclitaxel (n = 29) to describe local treatment patterns. Descriptive outcomes included pathological complete response (pCR), treatment delivery, adverse events, surgery completion, and exploratory event-free survival (EFS). Analyses were primarily descriptive; between-cohort comparisons were exploratory in nature. Results: Fifty-nine patients were included overall: 30 treated with the KN522 regimen and 29 treated with dose-dense neoadjuvant chemotherapy. In the KN522 cohort, the median age was 56 years, 80.0% of patients were postmenopausal, and 33.3% had N3 disease. Pathological complete response occurred in 13 of 30 patients (43.3%; exact 95% CI 25.5–62.6%). Grade ≥3 chemotherapy-related adverse events occurred in 15 patients (50.0%), immune-related adverse events occurred in 11 patients (36.6%), and Grade 3 or higher immune-related adverse events occurred in four patients (13.3%). Pembrolizumab was suspended in six patients (20.0%), while all 30 patients proceeded to definitive surgery. In the dose-dense chemotherapy cohort, the pCR rate was 31.0%, with a grade ≥3 chemotherapy-related adverse event rate of 20.7%, and all patients proceeded to definitive surgery. Conclusions: In this descriptive real-world single-centre Hong Kong study, the neoadjuvant KN522 regimen was feasible in Chinese patients with early TNBC, although treatment-related toxicity and treatment modification were common. The observed pCR rate was lower than that reported in the original KN522 trial, possibly reflecting differences in patient selection and real-world treatment delivery patterns. Larger multi-centre studies are needed to evaluate outcomes in Chinese and other Asian populations.
Source: Cancers
Authors: Yuk-Fong Grace Lo, Kuen Chan, Sung Inda Soong
Institution: Pamela Youde Nethersole Eastern Hospital
Language: English
Subfield: Cancer Research
Domain: Life Sciences
Open Access status: gold
Estimated APC paid: $3,499
OpenAlex ID: W7222508804