The CLEOPATRA trial established the combination of pertuzumab + trastuzumab + docetaxel as first-line standard for HER2-positive metastatic breast cancer. The primary endpoint demonstrating superiority was:

• A Pathological complete response (pCR) rate at surgery
• B Overall survival with a median gain of 15.7 months ✓
• C Progression-free survival (PFS) with median improvement of approximately 6 months
• D Objective response rate — superior in the pertuzumab arm

Explanation

The CLEOPATRA trial demonstrated that adding pertuzumab to trastuzumab+docetaxel resulted in a median overall survival of 56.5 months versus 40.8 months in the placebo arm — a gain of 15.7 months, the largest OS improvement ever seen in metastatic breast cancer at the time of publication. PFS was also significantly improved (18.5 vs 12.4 months). Pertuzumab binds HER2 at a different epitope than trastuzumab (domain II vs domain IV), preventing HER2-HER3 dimerization, providing complementary dual HER2 blockade.

Reference: Bailey & Love's Short Practice of Surgery, 27th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.