Palbociclib in combination with endocrine therapy versus capecitabine in hormonal receptor-positive, human epidermal growth factor 2-negative, aromatase inhibitor-resistant metastatic breast cancer: a phase III randomised controlled trial-PEARL
Mené sur 296 et 305 patientes atteintes d'un cancer du sein HR+ HER2- de stade métastatique et résistant aux inhibiteurs de l'aromatase, cet essai de phase III compare l'efficacité, du point de vue de la survie sans progression, et la toxicité d'une chimiothérapie par capécitabine et d'un traitement endocrinien en combinaison avec le palbociclib
Background : Palbociclib plus endocrine therapy (ET) is the standard treatment for hormone receptor-positive and human epidermal growth factor receptor 2-negative, metastatic breast cancer (MBC). However, its efficacy has not been compared with that of chemotherapy in a phase III trial. Patients and Methods : PEARL is a multicentre, phase III randomised study in which patients with aromatase inhibitors (AIs)-resistant MBC were included in two consecutive cohorts. In cohort 1 (C1), patients were randomised 1:1 to palbociclib plus exemestane or capecitabine. On discovering new evidence about oestrogen receptor-1 (ESR1) mutations inducing resistance to AIs, the trial was amended to include cohort 2 (C2), in which patients were randomised 1:1 between palbociclib plus fulvestrant and capecitabine. The stratification criteria were disease site, prior sensitivity to ET, prior chemotherapy for MBC, and country of origin. Co-primary endpoints were progression-free survival (PFS) in C2 and in wild-type ESR1 patients (C1+C2). ESR1 hotspot mutations were analysed in baseline circulating tumour DNA. Results : From March-2014 to July-2018, 296 and 305 patients were included in C1 and C2, respectively. Palbociclib plus ET was not superior to capecitabine in both C2 (median PFS: 7.5 vs. 10.0 months; adjusted hazard ratio [aHR]: 1.13; 95% confidence Interval [CI]: 0.85-1.50) and wild-type ESR1 patients (median PFS: 8.0 vs. 10.6 months; aHR: 1.11; 95% CI: 0.87-1.41). The most frequent grade 3-4 toxicities with palbociclib plus exemestane, palbociclib plus fulvestrant, and capecitabine were neutropenia (57.4%, 55.7% and 5.5%), hand/foot syndrome (0%, 0% and 23.5%), and diarrhoea (1.3%, 1.3% and 7.6%). Palbociclib plus ET offered better quality of life (aHR for time to deterioration of global health status: 0.67; 95% CI: 0.53-0.85). Conclusions : There was no statistical superiority of palbociclib plus ET over capecitabine with respect to PFS in MBC patients resistant to AIs. Palbociclib plus ET showed a better safety profile and improved quality of life.
Annals of Oncology 2020