- The end-of-study results of the CLEOPATRA phase 3 trial reveal that first-line treatment of HER2+ metastatic breast cancer (mBCa) with pertuzumab plus trastuzumab and docetaxel offers an OS advantage of 16.3 months vs placebo plus trastuzumab and docetaxel.
Why this matters
- Results confirm previous report at 56.5 months of a pertuzumab advantage of 15.7 months.
- Results support pertuzumab's status as first-line treatment with trastuzumab and docetaxel in HER2+ mBCa.
- Double-blind, randomized, placebo-controlled phase 3 trial with pertuzumab (420 mg) plus trastuzumab (6 mg/kg) and docetaxel (up to 100 mg/m2; n=402) until disease progression vs placebo plus trastuzumab and docetaxel (n=406).
- Funding: F Hoffmann-La Roche; Genentech.
- Median follow-up: pertuzumab, 99.9 months; placebo, 98.7 months.
- Pertuzumab group had longer OS:
- 57.1 (95% CI, 50-72) months vs 40.8 (95% CI, 36-48) months with placebo.
- Difference: 16.3 months.
- HR, 0.69 (95% CI, 0.58-0.82).
- 8-year landmark OS rates favored pertuzumab:
- 37% (95% CI, 31%-42%) vs placebo, 23% (95% CI, 19%-28%).
- Pertuzumab group had somewhat higher rates of grade 3-4 neutropenia (49% vs 46% of placebo patients), the most common adverse event.
- Since the previous analysis, 1 new serious adverse event arose suggestive of congestive heart failure in the pertuzumab group.
- Analyses are descriptive.