Dr. Kang on Key Results From the PALOMA-2 and PALOMA-3 Trials in Advanced Breast Cancer

Irene Morae Kang, MD, medical director of women’s health medical oncology and assistant professor in the Department of Medical Oncology & Therapeutics Research, City of Hope, discusses key overall survival (OS) data from the phase 3 PALOMA-2 (NCT01740427) and PALOMA-3 (NCT01942135) trials, which evaluated the addition of palbociclib (Ibrance) to standard endocrine therapy for patients with advanced breast cancer.

The PALOMA-2 study investigated the use of palbociclib in combination with letrozole vs placebo plus letrozole in the first-line setting for postmenopausal women with advanced hormone receptor (HR)–positive, HER2-negative breast cancer. Although the study did demonstrate progression-free survival (PFS) benefit with the combination therapy vs placebo, it did not show a significant difference in OS, Kang explains.

The PALOMA-3 study built upon this data by evaluating the efficacy of palbociclib in patients who failed prior endocrine therapy. Palbociclib was administered in combination with fulvestrant (Faslodex), and compared with placebo plus fulvestrant, Kang continues. The trial did demonstrate a PFS benefit with palbociclib compared with placebo, as well as a median OS improvement of 7 months. Although OS benefit was numerically higher in the palbociclib arm compared with placebo, it was not statistically significant, Kang notes.

Both the PALOMA-2 and PALOMA-3 trials indicate that palbociclib is not as effective or beneficial in the advanced setting for this patient population as other CDK4/6 inhibitors, Kang concludes.