Dr Ali on the Potential SOC Role of Palbociclib Plus Anti-HER2 and Endocrine Therapy in HER2+ Breast Cancer

"What we're seeing is a 15-month improvement in PFS [with palbociclib plus SOC anti-HER2 and endocrine therapy vs the SOC] in that first-line [setting]. The data look very exciting. We await more information on this study, and hopefully an FDA approval."

Azka Ali, MD, a medical oncologist in the Department Hematology and Medical Oncology at the Cleveland Clinic Taussig Cancer Institute, discusses how findings from the phase 3 AFT-38 PATINA trial (NCT02947685) support the addition of palbociclib (Ibrance) to anti-HER2 and endocrine therapy as a new standard of care (SOC) in the maintenance setting for patients with hormone receptor–positive, HER2-positive metastatic breast cancer.

According to results from the AFT-38 PATINA trial presented during the 2024 San Antonio Breast Cancer Symposium, the addition of palbociclib to SOC trastuzumab (Herceptin) with or without pertuzumab (Perjeta) and endocrine therapy produced a statistically significant and clinically meaningful improvement in progression-free survival (PFS) in this patient population in the first-line maintenance setting, Ali reported. The palbociclib regimen (n = 261) resulted in a median PFS of 44.3 months (95% CI, 32.4-60.9) compared with 29.1 months (95% CI, 23.3-38.6) for SOC therapy alone (n = 257; HR, 0.74; 95% CI, 0.58-0.94; unstratified 1-sided P = .0074). The median follow-up was 52.6 months among patients who remained alive and disease free.

Subgroup analyses of PFS also favored the addition of palbociclib across clinically relevant cohorts. Among patients with prior exposure to anti-HER2 therapy, the HR for PFS was 0.76 (95% CI, 0.57-1.01); among those without prior anti-HER2 exposure, the HR was 0.68 (95% CI, 0.54-1.07).

These data suggest that the addition of palbociclib to anti-HER2 therapy and endocrine therapy may represent a potential new SOC in the maintenance setting for patients with hormone receptor–positive, HER2-positive disease, Ali asserted. Ongoing follow-up is anticipated, and regulatory review will further inform the clinical utility of this regimen in routine practice, Ali concluded.