Addition of Palbociclib Shows Benefit in Double-, Triple-Positive Metastatic Breast Cancer

Phase 3 results from the PATINA trial demonstrated that the addition of palbociclib, a CDK4/6 inhibitor, to the current standard of care—first-line maintenance therapy after induction chemotherapy—resulted in statistically significant and clinically meaningful improvement in progression-free survival in patients with hormone receptor-positive (HR+), human epidermal growth factor receptor 2-positive (HER2+) metastatic breast cancer. The study was sponsored by Alliance Foundation Trials, LLC.

Study participants with HR+ HER2+ metastatic disease who were previously treated with anti-HER2 therapy were randomly assigned to receive palbociclib in addition to anti-HER2 therapy and endocrine therapy (n=261) or anti-HER2 therapy and endocrine therapy alone (n=257). Progression-free survival was the primary endpoint.

Median PFS was 44.3 months (95% CI, 32.4-60.9) for patients treated with palbociclib in combination with anti-HER2 therapy (trastuzumab or trastuzumab-pertuzumab) and endocrine therapy, and 29.1 months (95% CI, 23.3-38.6) for patients treated with anti-HER2 therapy and endocrine therapy alone (hazard ratio [HR], 0.74; 95% CI, 0.58-0.94; unstratified one-sided P=.0074). This represents an extension of median PFS by more than 15 months.

One of the secondary endpoints, overall survival, was not yet mature enough at the time of analysis, with the results recently presented at the 47^th San Antonio Breast Cancer Symposium.

Otto Metzger, MD, one of the principal trial investigators, notes that “PATINA is the first large phase III study to show the benefit of CDK4/6 inhibitor in HR-positive, HER2-positive metastatic breast cancer,” thus supporting the potential to slow disease progression and improve clinical outcomes.

Source

Pfizer’s IBRANCE in combination with standard-of-care therapies extends median progression-free survival by over 15 months in Phase 3 PATINA study in patients with HR+, HER+ metastatic breast cancer.