Overview of the PATINA Trial
- Full Name & Design
PATINA (AFT-38; ClinicalTrials.gov NCT02947685) is a randomized, open-label Phase III study examining whether adding palbociclib (IBRANCE®)—a CDK4/6 inhibitor—to standard maintenance therapy (anti-HER2 + endocrine therapy) improves outcomes in hormone receptor–positive (HR+), HER2-positive metastatic breast cancer (MBC), after initial induction chemotherapy. - Participants & Treatment Setup
Approximately 518 patients were randomized (261 to the palbociclib arm versus 257 controls). Maintenance therapy included trastuzumab ± pertuzumab plus letrozole, anastrozole, exemestane, or fulvestrant.
Key Results
- Progression-Free Survival (PFS)
- Palbociclib arm: 44.3 months (95% CI: 32.4–60.9)
- Control arm: 29.1 months (95% CI: 23.3–38.6)
- This reflects an improvement of over 15 months, with a hazard ratio (HR) of 0.74 (p = 0.0074)
- Overall Survival (OS)
OS data remain immature, but early signals suggest potential benefit. At 3 years, OS rates were 87.0% versus 84.7%, and at 5 years, 74.3% versus 69.8% (HR ≈ 0.86)
Safety Profile
- Common adverse events mirrored those known for palbociclib:
- Hematologic toxicities, especially neutropenia (grade 3 in ~63%, grade 4 in ~5%)
- Other side effects: mild-to-moderate fatigue, diarrhea, stomatitis
- Grade 4+ adverse events occurred in 12.3% vs 8.9% in control, and treatment discontinuation due to AEs was ~7.5%
Clinical Context & Implications
- The trial represents a major shift in treating HR+/HER2+ MBC by combining endocrine therapy with both HER2-targeted and CDK4/6 inhibition
- PATINA challenges prior trial designs that separated HER2 and hormone receptor targeting, showing that dual pathway blockade can yield substantial survival gains (nearly 4 years PFS without chemo)
- These results may well reshape standard of care and are considered practice-changing—with guideline inclusion expected once regulatory updates follow
