Background:
The real-world effectiveness of neoadjuvant pembrolizumab in triple-negative breast cancer (TNBC) remains insufficiently characterized, particularly in resource-limited settings.
Methods:
We conducted a retrospective analysis of 33 patients with non-metastatic TNBC treated with neoadjuvant pembrolizumab between 2023 and 2025 at a single tertiary center. Clinical, pathological, and treatment-related variables, including number of pembrolizumab cycles, inter-cycle delays, and chemotherapy backbone, were collected. The primary endpoint was pathological complete response (pCR; RCB 0). Secondary endpoints included relapse-free survival (RFS). Kaplan–Meier estimates were used for survival analysis.
Results:
Median age was 48 years, with most patients presenting with stage II–III disease. The overall pCR rate was 33.3%, lower than rates reported in pivotal trials. Smaller tumor size was significantly associated with higher pCR (p = 0.036), with a trend toward improved response in premenopausal patients. Despite observable heterogeneity in treatment delivery, no statistically significant association was identified between pCR and number of pembrolizumab cycles, inter-cycle delays, or chemotherapy regimen. At a median follow-up of 12 months, the estimated 1-year RFS was 72%. No relapses occurred among patients achieving pCR, while non-pCR patients had a 1-year RFS of 63%. A clear prognostic gradient was observed according to residual cancer burden, with poorer outcomes in RCB III patients.
Conclusion:
In this real-world North African cohort, pCR rates with neoadjuvant pembrolizumab were lower than those reported in clinical trials. Although no direct association was observed between treatment delivery parameters and pathological response, these findings may reflect the cumulative impact of real-world treatment constraints, including variability in access and exposure. This highlights the challenges of implementing immunotherapy in resource-limited settings and underscores the need for strategies to optimize treatment delivery in underrepresented populations.