Abstract PO1-05-06: Health-related QOL and physical activity collected via wearable device in patients with HR+/HER2− advanced breast cancer in Japan treated with palbociclib+endocrine therapy (ET) or ET alone: 6-month longitudinal study (JBCRG-26)

Abstract Background: Palbociclib (PAL) is a first-in-class cyclin-dependent kinase 4/6 inhibitor (CDK4/6i) for the treatment of HR+/HER2− advanced breast cancer (ABC). In phase 3 clinical trials, PAL+ET prolonged progression-free survival and maintained health-related quality of life (HRQOL) compared with placebo+ET. However, few studies have evaluated the day-to-day effects of PAL+ET treatment on patients’ HRQOL and daily activities in a real-world setting. Here, we report the daily life of the patients treated with PAL+ET or ET alone evaluated with a mobile application and wearable device. Methods: This is a prospective, observational, multicenter study conducted in Japanese women with HR+/HER2- ABC initiating PAL+ET (Group 1) or ET alone (Group 2) in first- or second-line setting. HRQOL was assessed with the EORTC-QLQ-C30 at baseline and Day 15 of each cycle via a smartphone-based application for 6 treatment cycles (24 weeks). Physical activity (PA) data were collected via wearable device (CentrePoint Insight Watch®, ActiGraph LLC, the USA). Patients were instructed to wear the device at all-times, except of while bathing and sleeping, during the baseline period (at least 4 days prior to treatment initiation was recommended) and 6 cycles. PA metrics were averaged on a weekly basis. Patient data, including baseline characteristics, treatment, and adverse events, were collected via electronic case report forms. As primary endpoints, change in Global health status (GHS) of EORTC-QLQ-C30 and “sedentary time” from baseline were evaluated at each time point. No formal hypothesis testing or comparisons between groups was planned. Results: Ninety-nine patients were enrolled (Group 1: 78 patients, Group 2: 21 patients). Patients had a median age of 56/52 years (Group 1/Group 2); 51%/33% had visceral metastases; 86%/86% had ECOG performance status of 0; 76%/91% initiated first-line treatment; 36%/33% were fully employed. Seventy-four of 78 patients (95%) in Group 1 and 20 of 21 patients (95%) in Group 2 completed the 6-cycle observation period. Baseline mean GHS score was 60.9 and 64.3 in Group 1 and 2, respectively. The change from baseline to Cycle 6 in GHS score was 4.6 and 1.2 in Group 1 and 2, respectively, not reaching the deterioration-threshold of 8 points in either treatment group. Results for each functional subscale are summarized in Table 1. Baseline mean “sedentary time” was 580.7 and 565.1 min/day in Group 1 and 2, respectively. The change from baseline to Cycle 6 in “sedentary time” was —67.2 and —139.4 min/day in Group 1 and 2, respectively. Results of other PA metrics are summarized in Table. No new safety signals were identified. Conclusion: In this study, PAL+ET or ET alone did not have any significant adverse impact on HRQOL and PA measured by wearable devices in patients with HR+/HER2- ABC. (NCT04736576) Citation Format: Hiroko Bando, Mari Oba, Aya Ueda, Kaori Terata, Mihoko Doi, Shigenori Nagai, Masaya Hattori, Ken-Ichi Watanabe, Nobuko Tamura, Manabu Futamura, Kei Koizumi, Naoki Niikura, Tempei Miyaji, Yasuaki Muramatsu, Linghua Xu, Norikazu Masuda, Shigehira Saji. Health-related QOL and physical activity collected via wearable device in patients with HR+/HER2− advanced breast cancer in Japan treated with palbociclib+endocrine therapy (ET) or ET alone: 6-month longitudinal study (JBCRG-26) abstract. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO1-05-06.