Introduction: The Challenge of Triple-Negative Breast Cancer
Triple-negative breast cancer (TNBC) remains one of the most clinically challenging subtypes of breast cancer due to its aggressive nature, high risk of early recurrence, and lack of targeted hormone receptors or HER2 expression. For years, the backbone of treatment was restricted to cytotoxic chemotherapy. However, the advent of immune checkpoint inhibitors (ICIs) has revolutionized the management of localized TNBC. The landmark KEYNOTE-522 trial established the combination of pembrolizumab and neoadjuvant chemotherapy (NACT) as the global standard of care, significantly improving pathological complete response (pCR) and event-free survival.
Despite these advances, the high cost of standard-dose pembrolizumab (200 mg every three weeks) remains a prohibitive barrier for many patients, particularly in low- and middle-income countries (LMICs). The PLANeT trial (Pembrolizumab Low Dose in Addition to NACT in TNBC) was designed to address this disparity by evaluating whether a significantly lower dose of pembrolizumab could yield comparable clinical benefits.
