Phase 2 NeoTHERa tests HER2 dual-antibody blockade (trastuzumab/pertuzumab) with taxane ± platinum

University of Kansas Medical Center is running this randomized Phase 2 neoadjuvant study in stage II–III HER2-amplified/positive early breast cancer to compare pCR after 6 cycles (every 21 days) of THP vs TCHP before surgery. Arm A adds carboplatin (a platinum DNA crosslinking agent that blocks DNA replication/repair) to docetaxel (a microtubule-stabilizing taxane that disrupts mitosis) plus trastuzumab and pertuzumab (Genentech/Roche anti-HER2 monoclonal antibodies; trastuzumab inhibits HER2 signaling and mediates ADCC, while pertuzumab blocks HER2 dimerization), while Arm B omits carboplatin to test de-escalation. Eligible patients include cT2–T3 N0–N2, cT1 N1–N2, or cTX N1–N2 disease that is HER2 amplified/positive. The key commercial/scientific angle is whether platinum can be safely removed without materially lowering pCR—important because carboplatin often increases hematologic toxicity and supportive-care burden. Today’s care for higher-risk HER2+ early breast cancer commonly uses neoadjuvant taxane + carboplatin + trastuzumab/pertuzumab followed by surgery, then adjuvant anti-HER2 therapy (and escalation to ado-trastuzumab emtansine when residual disease persists), so this trial directly tests a practical neoadjuvant simplification strategy.