Palbociclib plus endocrine therapy versus capecitabine for premenopauzal HR+ HER2- mBC: overall survival in Young-PEARL

The phase 2 Young-PEARL study, at 14 centers in South Korea, randomized patients with HR-positive, HER2-negative metastatic breast cancer previously treated with tamoxifen, 1:1 to palbociclib plus endocrine therapy or capecitabine. The primary analysis of the study showed a progression-free survival benefit in the palbociclib plus endocrine therapy group. Extended follow-up of the study has now been published. The PFS was still better with palbociclib plus endocrine therapy compared with capecitabine (median 19.5 versus 14.0 months; HR 0.74; p=0.036) but the overall survival was not (median 54.8 versus 57.8 months; HR 1.02; p=0.92). The most common grade 3 or worse adverse event was neutropenia (64% of patients with palbociclib plus endocrine therapy versus 18% of patients with capecitabine). The authors conclude that among HR+ HER2- mBC patients previously treated with tamoxifen, palbociclib plus endocrine therapy showed a significant PFS benefit but no OS benefit compared with capecitabine.