Assessing the impact of scalp cooling in patients receiving trastuzumab deruxtecan for metastatic breast cancer.

Abstract

1095 Background: Outcomes for patients (pts) with metastatic breast cancer (MBC) have improved with novel antibody drug conjugates like trastuzumab deruxtecan (T-DXd). While T-DXd has been associated with increased risk of alopecia, there are limited data describing the efficacy of scalp cooling in preventing alopecia and improving quality of life among pts receiving T-DXd. Methods: This prospective, phase II study enrolled pts with MBC without alopecia at baseline who were initiating treatment with T-DXd; pts elected to participate in a scalp cooling (SC) arm with the Paxman scalp cooling system or a non-SC arm. The primary endpoint was hair loss, defined as locally assessed CTCAE v5.0 grade ≥1 alopecia occurring at C3D1, C5D1, or end of treatment (EOT), whichever occurred first. The impact of SC on quality of life (QOL) was assessed using the Chemotherapy-Induced Alopecia Distress Scale (CADS) and body image scale (BIS) at baseline, C3D1, C5D1, and EOT. The study aimed to enroll 20 pts per arm to provide at least 80% power to detect a 28% decrease in hair loss rate between the SC vs non-SC arms (8% vs 36%) using a difference in proportions test (one-sided type I error 10%). Results: A total of 40 evaluable pts were enrolled: 20 in SC arm and 20 in non-SC arm. Median age was 61 (33-77); 2 (5%) were Black, 2 (5%) were Hispanic. Twenty-eight (70%) pts had hormone receptor positive disease, 11 (27.5%) HER2+, 2 (5.0%) triple-negative. Thirty-five (87.5%) had prior chemotherapy for MBC; median prior lines was 1 [range: 0-5]. 27 (67.5%) had prior endocrine therapy, 28 (70.0%) had prior CDK4/6 inhibition; 7 (17.5%) had prior use of SC. Thirty-three (82.5%) pts (18 [90%] in SC arm, 15 [75%] in non-SC arm) experienced >grade 1 alopecia, with similar rates observed in both arms (p = 0.41). Grade 2 alopecia was the main reason (45%) for SC discontinuation. Median time to G2 alopecia was 2.76 months (95% CI: 1.64-NA) in SC arm and 4.60 months (95% CI: 2.53, NA) in non-SC arm (p = 0.8). Median CADS scores trended upward from baseline to EOT (Baseline: 3.50; C3: 7.22; C5: 9.00; EOT: 11.5) in the SC arm and were more variable in the non-SC arm (baseline: 3.00; C3: 5.00; C5: 2.56; EOT: 6.50); median BIS scores trended upward in both the SC (baseline: 3.00; C3: 8.00; C5: 9.00; EOT: 11.5) and non-SC arms (baseline: 3.00; C3: 5.00; C5: 5.00; EOT: 9.00), with no statistically significant difference. Conclusions: In this prospective phase II trial, the use of SC with T-DXd did not show a benefit in hair preservation vs no SC. QOL analysis was not significantly different for those receiving SC vs no SC. Small sample size and lack of randomization may limit interpretation of results. Further work is planned to investigate strategies to improve efficacy of SC with ADCs. Clinical trial information: NCT04986579 . CTCAE v5 alopecia. CTCAE v5 Alopecia AllN=40 SC ArmN=20 Non-SC ArmN=20 P-value No alopeciaGrade 1 Grade 2 7(17.5%)11(27.5%)22(55.0%) 2(10.0%)7(35.0%)11(55.0%) 5(25.0%)4(20.0%)11(55.0%) 0.41