188P A health-related quality-of-life (HRQoL) analysis from DESTINY-Breast04: Trastuzumab deruxtecan (T-DXd) vs capecitabine (CAP) in patients (Pts) with hormone receptor-positive (HR+), HER2-low metastatic breast cancer (mBC)

In DESTINY-Breast04 (NCT03734029), 494 pts were assigned to T-DXd or treatment of physician's choice (TPC), including CAP. Progression-free survival and overall survival favored T-DXd vs TPC in pts with HR+, HER2-low (immunohistochemistry 1+ or 2+/in situ hybridization negative) mBC. Still, CAP is often considered to have a smaller negative impact on HRQoL vs T-DXd. We report a HRQoL analysis of T-DXd vs CAP. Before randomization into the DESTINY-Breast04 trial, a subgroup of 95 pts with HR+, HER2-low mBC were pre-assigned to CAP to ensure TPC arm assignment. At randomization, 61 of those pts were assigned to T-DXd and 34 pts to CAP (3-wk treatment cycles). PRO data were collected at prespecified timepoints during treatment using the European Organization for Research and Treatment of Cancer QoL questionnaires (EORTC QLQ)-C30 and the breast cancer–specific EORTC QLQ-BR45 (scored as EORTC-QLQ-BR23). Change from baseline (CFB) and time to definitive deterioration (TDD) were assessed. Survey compliance rate was >80% throughout treatment. Total patient-years of exposure was 49.1 for T-DXd and 16.4 for CAP. Baseline mean Global Health Status (GHS/QoL) score was 61.5 for T-DXd and 62.6 for CAP. Mean CFB for GHS/QoL was stable (within ±10 points) up to cycle 27 for T-DXd and cycle 21 for CAP, after which numbers of pts on treatment were too low for analysis. TDD hazard ratios for pain and arm symptoms favored T-DXd vs CAP; hazard ratios for the remaining scales were not significant.Table: 188PTDD for prespecified scales from EORTC QLQ-C30 and QLQ-BR45Median (95% CI), monthsT-DXd n = 61CAP n = 34T-DXd vs CAP Hazard ratio (95% CI)QLQ-C30GHS/QoL13.1 (8.4-20.8)10.5 (3.5-15.5)0.68 (0.37-1.23)Pain16.7 (10.9-NE)7.0 (1.5-10.5)0.42 (0.23-0.78)Physical functioningNE (13.1-NE)11.7 (4.2-NE)0.68 (0.34-1.34)Emotional functioning21.7 (10.5-NE)11.7 (6.5-NE)0.89 (0.44-1.79)Social functioning12.8 (5.6-NE)9.7 (4.7-NE)1.00 (0.54-1.84)QLQ-BR45Breast symptomsaNE (NE-NE)NE (NE-NE)1.33 (0.43-4.14)Arm symptoms11.5 (7.0-NE)5.1 (1.9-16.9)0.55 (0.30-0.99)NE, not estimable. aMedian (95% CI) not estimable due to low number of pts with deterioration events. Open table in a new tab NE, not estimable. aMedian (95% CI) not estimable due to low number of pts with deterioration events. Despite the hypothesis that CAP would have a smaller negative impact on HRQoL vs T-DXd, mean CFB results were similar between the 2 treatment arms, and median TDD results suggest a slower worsening in pain and arm symptoms for T-DXd. While the sample size was small, these results support a benefit of T-DXd vs CAP for pts with HR+, HER2-low mBC.