Quality of life with palbociclib plus tamoxifen in hormone receptor-positive, HER2-negative advanced breast cancer: results from PATHWAY, an Asian international, double-blind, randomized phase 3 trial.
BACKGROUND: In the Asian international PATHWAY trial, palbociclib-tamoxifen demonstrated improved progression-free survival compared with placebo-tamoxifen in patients with HR+/HER2- locally advanced or metastatic breast cancer (ABC). This analysis compared quality of life (QoL) between treatment arms. METHODS: Pre/peri or postmenopausal women with HR+/HER2- ABC were randomly assigned 1:1 to receive palbociclib-tamoxifen or placebo-tamoxifen. Patient-reported outcomes were assessed on day 1 of cycles 1 (baseline), 4, and 7, and at the end of treatment (EOT) using the EORTC QLQ-C30 and QLQ-BR23 questionnaires. Least-square mean (LSM) changes in scores from baseline were calculated. Kaplan-Meier method was used to calculate time to deterioration (TTD) in the minimally important difference (MID) in the pain subscale. RESULTS: In the comparison between treatment arms, no significant differences were observed in LSM changes in scores from baseline in global QoL (cycle 4: 0.70 [95% confidence interval (CI): -5.00, 6.41]; cycle 7: 2.17 [95% CI: -4.14, 8.48]; EOT: -5.19 [95% CI: -11.64, 1.26]). For both the EORTC QLQ-C30 and QLQ-BR23 functional and symptom subscales, no clinically meaningful differences between treatment arms were found in the LSM changes in scores from baseline. Median TTD in the MID in the pain subscale was 32.5 months (95% CI: 11.7, not estimable) for the palbociclib-tamoxifen arm and 21.2 months (95% CI: 5.5, 43.5) for the placebo-tamoxifen arm (hazard ratio = 0.729 [95% CI: 0.467, 1.138]). CONCLUSIONS: The combination of palbociclib and tamoxifen delayed deterioration in patients' QoL while they experienced reduced risk for disease progression. TRIAL REGISTRATION: ClinicalTrials.gov: NCT03423199; study registration date: February 6, 2018.