A Prospective, Single-center, Phase II Study of Sacituzumab Tirumotecan in Combination With Pembrolizumab for Neoadjuvant Treatment of Triple-Negative Breast Cancer (TNBC)

This is a prospective, single center, phase II study to enroll participants with stage II or III TNBC who have not previously undergone systemic therapy. The primary endpoint is pCR in the ITT population. The study aims to enroll 52 participants. Eligible participants will receive a combination therapy of SKB264 and Pembrolizumab.

Experimental arm: SKB264 will be administered intravenously (IV) at a dose of 4 mg/kg every two weeks (Q2W); Pembrolizumab will be administered intravenously at a dose of 200mg every three weeks (Q3W) All enrolled participants will initially receive SKB264 plus Pembrolizumab for 8 weeks. Based on early imaging and biopsy assessment, patients who deemed as responders continue to receive combined drug therapy for 10 weeks, followed by surgical treatment. Patients who assessed as non-responders will be treated at the discretion of the physician.

Participants will undergo regular tumor assessments based on RECIST 1.1 criteria. Imaging assessments will be conducted every 9 weeks (±1 week) for the first 18 weeks following treatment initiation, and every 12 weeks (±1 week) thereafter, until confirmed disease progression, initiation of a new antitumor treatment, withdrawal of consent, loss to follow-up, death, or study end, whichever occurs first. After termination of the study treatment, participants must complete the EOT visit and a safety follow-up, and undergo survival visits every 3 months (±14 days) post the last dose to collect information on survival, new antitumor treatments received.