Addition of low-dose pembrolizumab to capecitabine for residual triple negative breast cancer post neoadjuvant chemotherapy: An investigator-initiated multicentric open-labelled phase III randomized controlled clinical trial

Triple negative breast cancer (TNBC) is the most aggressive subtype of breast cancer, and is associated with worse long-term survival outcomes when compared with other subtypes, even for early stage disease (1). The preferred approach for treating patients with TNBC has evolved to include neoadjuvant chemotherapy (NACT) followed by surgery(2). This approach provides an opportunity to assess the pathological response to chemotherapy in the resected specimen. Pathological complete response (PCR), although not a sine qua non of cure in TNBC, is unequivocally associated with significantly better long-term survival when compared to those who have residual disease after neoadjuvant chemotherapy (NACT)(3). Despite several advances, around 50-60% of patients with TNBC treated with NACT followed by surgery will have residual disease after NACT(4). Capecitabine is the current standard of care for these patients(5).

Rationale

The study addresses a large unmet need for incorporating immunotherapy in treating patients with TNBC in resource-limited settings.(12)

Hypothesis/ Research question

We hypothesize that the addition of low-dose pembrolizumab (50 mg flat dose q6 weekly for 4 cycles) to capecitabine in patients with residual disease after neoadjuvant chemotherapy will improve invasive disease-free survival as compared with capecitabine.