Dr Yuan on Dual-Pathway Targeted Strategies in ER+/HER2+ Breast Cancer

"The [PATINA regimen] should be adopted now for every single patient we have in the HR-positive, HER2-positive space. It's a very welcome strategy [and shows how our learnings] from ER-positive, [HER2-negative] disease can now translate into the double-positive patient population."

Yuan Yuan, MD, PhD, the director of Breast Medical Oncology Medicine and the medical director of the Breast Oncology Disease Research Group at Cedars-Sinai Medical Center, as well as a health sciences clinical professor at the University of California, Los Angeles, discussed findings from the phase 3 PATINA trial (NCT02947685) and the potential effect of these findings treatment strategy for patients with hormone receptor–positive, HER2-positive metastatic breast cancer.

PATINA evaluated whether sustained inhibition of both the estrogen receptor (ER) signaling pathway and the HER2 pathway could improve outcomes following first-line induction therapy. According to current National Comprehensive Cancer Network (NCCN) guidance, maintenance aromatase inhibitor therapy combined with dual HER2-targeted treatment is standard; however, progression-free survival (PFS) remains limited for many patients in this double-positive population. PATINA investigated whether augmenting maintenance therapy with a CDK4/6 inhibitor may better address the dual-driver biology characteristic of these tumors.

In PATINA, patients received 6 cycles of docetaxel, pertuzumab (Perjeta), and trastuzumab (Herceptin) consistent with the phase 3 CLEOPATRA (NCT00567190) regimen, followed by maintenance therapy with an aromatase inhibitor plus palbociclib (Ibrance), a CDK4/6 inhibitor, in combination with continued trastuzumab (Herceptin) and pertuzumab (Perjeta). Yuan emphasized that this strategy aims to improve disease control by targeting both key proliferative pathways concurrently.

Results demonstrated a clinically meaningful prolongation in PFS with the addition of palbociclib, supporting its use as part of maintenance therapy in this population. Yuan noted that these findings align with additional emerging evidence, including a Korean study exploring a similar therapeutic approach, reinforcing the importance of optimizing dual-pathway targeting in ER-positive, HER2-positive metastatic disease.

She stated that this represents a “very welcome strategy,” translating established benefits of CDK4/6 inhibitors from hormone receptor–positive, HER2-negative disease into the double-positive metastatic setting. Yuan concluded by suggesting that incorporation of this approach into routine clinical practice should now be strongly considered for eligible patients.