A phase 3 study (PATHWAY) of palbociclib plus tamoxifen in patients with HR-positive/HER2-negative advanced breast cancer

In a double-blind phase III study, researchers investigated the efficacy and safety of palbociclib plus tamoxifen in patients with HR+ HER2- advanced breast cancer. Progression-free survival (PFS) benefits were seen in patients who received palbociclib plus tamoxifen across many subgroups, including patients treated with first- or second-line endocrine therapy, as well as in patients who were pre-, peri-, and postmenopausal. The median PFS for patients who received palbociclib plus tamoxifen was 24.4 months, compared with 11.1 months for patients who received placebo plus tamoxifen. Although the overall survival data are still immature, at the time of PFS analysis, there was an overall risk reduction of 27% seen in the palbociclib plus tamoxifen group.