BACKGROUND: Breast cancer is the most common malignancy diagnosed in women worldwide. Triple-negative breast cancer (TNBC) is the most aggressive subtype, accounting for nearly one third of all breast cancers in India. The addition of pembrolizumab to neoadjuvant chemotherapy improved the pathological response and event free survival in patients with TNBC. However, for most patients in low- and middle-income countries, immunotherapy remains inaccessible due to its high cost. Pharmacological and early clinical data suggest that a lower dose of pembrolizumab may be effective. However, there are no prospective clinical trials in patients with TNBC. METHODS: This is a single-site phase II, randomized, open-labeled, parallel-group trial. Eligible patients will be randomized (1:1) to either of the two treatment groups. Patients in the control arm will be administered standard of care chemotherapy [4 cycles of dose-dense doxorubicin (60 mg/m DISCUSSION: The PLANeT trial aims to establish the efficacy of low-dose pembrolizumab in addition to neoadjuvant chemotherapy in patients with triple-negative breast cancer patients. This strategy, if found effective, will help improve the outcomes of women with TNBC who currently have limited access to pembrolizumab. TRIAL REGISTRATION: Clinical Trials Registry of India-CTRI/2024/01/062088.