Dr Desai on the PATINA Study of a Palbociclib-Based Regimen in HR+/HER2+ Metastatic Breast Cancer

“In this trial, at that juncture of maintenance therapy, patients were [randomly assigned] to [receive trastuzumab, pertuzumab], and endocrine therapy with or without palbociclib. What this study showed was that the addition of palbociclib [to this regimen] led to a 15-month improvement in progression-free survival.”

Neelam Desai, MD, a breast medical oncologist and hematologist at the Atrium Health Levine Cancer Institute, highlighted the phase 3 PATINA study (NCT02947685) that evaluated the efficacy and safety of palbociclib (Ibrance) plus anti-HER2 therapy and endocrine therapy for the treatment of patients with hormone receptor–positive/HER2-positive metastatic breast cancer.

The randomized, international, open-label study specifically assessed the efficacy and safety of palbociclib added to trastuzumab (Herceptin) with or without pertuzumab (Perjeta), plus endocrine therapy with an aromatase inhibitor or fulvestrant (Faslodex); ovarian suppression required for patients who are premenopausal. Patients in the control arm received anti-HER2 therapy plus endocrine therapy alone.

For patients with hormone receptor–positive/HER2-positive metastatic breast cancer, the current standard of care is induction taxane with trastuzumab plus pertuzumab, Desai began. Furthermore, after 6 to 8 cycles, she noted that taxane is stopped as trastuzumab and pertuzumab are continued. For those with hormone receptor–positive disease, endocrine therapy is then added, she said.

In PATINA, the addition of palbociclib demonstrated an improvement in progression-free survival (PFS) of approximately 15 months, although the overall survival data were not yet mature, Desai said. At the data cutoff of October 15, 2024, and at a median follow-up of 53 months, the median PFS was 44.3 months (95% CI, 32.4-60.9) compared with 29.1 months (95% CI, 23.3-38.6) in the palbociclib and control arms, respectively (HR, 0.74; 95% CI, 0.58-0.94; 1-sided P = .0074). Moreover, the confirmed objective response rate was 29.2% vs 22.2% (P = .0458) in the respective arms, with a clinical benefit rate of 89.3% vs 81.3%, which favored the palbociclib arm (2-sided P = .0106).