ShortStop-HER2: Shortened Duration of Adjuvant Therapy in Patients with Early-Stage HER2+ Breast Cancer Who Achieve pCR After Neoadjuvant Chemotherapy with HER2 Blockade
Objective
To evaluate whether 6 months of combined neo/adjuvant HER2 blockade results in a non-inferior recurrence-free survival (RFS) compared to 12 months of combined neo/adjuvant HER2 blockade, in patients with early stage HER2+ breast cancer who achieve pCR after neoadjuvant chemotherapy with HER2 blockade.
Hypothesis: Patients with clinical stage I-III HER2+ breast cancer who achieve a pCR after neoadjuvant chemotherapy with HER2 blockade and receive a total of 6 months of HER2 blockade in the combined neoadjuvant + adjuvant (neo/adjuvant) setting will NOT have inferior (RFS) compared to patients who receive the standard total of 1 year of HER2 blockade.
Secondary objectives are to evaluate whether 6 months compared to 12 months results in differences for the following: Grade 3 or higher AE rates Overall survival (OS) Locoregional recurrence (LRR, both isolated LRR as first events, and LRR events simultaneous with distant metastasis [DM]) incidence RFS for key subgroups: baseline stage, HR status, neoadjuvant chemotherapy backbone, and dual versus single HER2 blockade in the adjuvant setting Time to central nervous system (CNS) recurrence (both isolated CNS recurrence as first events, and CNS recurrence events simultaneous with distant metastasis and/or LRR)
