A randomized study comparing electronic patient-reported outcome (ePRO) monitoring with routine follow-up during trastuzumab deruxtecan treatment in patients with metastatic breast cancer (PRO-DUCE study).

1504 Background: Trastuzumab deruxtecan (T-DXd) is a highly effective agent for HER2-positive metastatic breast cancer (MBC), but is associated with adverse events such as nausea, fatigue, and interstitial lung disease. Based on recent studies showing that symptom monitoring and alert notifications via ePROs could improve patient quality of life (QoL) and prognosis, we hypothesized that employing this method may diminish the treatment burden for patients receiving T-DXd. Methods: In this multicenter, randomized controlled exploratory study (jRCTs031200387), we randomized patients with HER2-positive MBC eligible for T-DXd to either the ePRO monitoring (ePROm) group or the usual care (UC) group. ePROm involved weekly symptom and daily body temperature/SpO 2 reports via a smartphone or computer at home. If any symptoms exceeded the predetermined thresholds, an email alert was sent to the medical staff, the ePRO was evaluated, and, if necessary, a phone consultation was provided. The primary endpoint was the change in the Global QoL score of EORTC QLQ-C30 from baseline at week 24. Secondary endpoints included score changes in the functional and symptom scales of EORTC QLQ-C30, and the time to deterioration of Global QoL (defined as a 10-point decrease from baseline). For a score difference between groups of 10 points and a standard deviation of 24, the required number of patients was 55 in each group, with a two-sided alpha error of 10% and a power of 87%. We analyzed the primary endpoint using a mixed-effects model for repeated measures. Results: Between March 2021 and January 2023, 111 patients were enrolled at 38 hospitals in Japan, with 56 assigned to ePROm and 55 to UC; the full-analysis set for QoL assessment included 54 and 52 patients, respectively. During the 24-week period, there were 1223 ePRO reports (95% compliance rate) in the ePROm group, including 427 alert notifications (7.9 per patient) to healthcare providers. Overall compliance with the questionnaire for QoL was 97%. Mean changes from baseline scores in Global QoL at week 24 showed that ePROm was significantly better than UC (mean difference 8.0 90% CI 0.2, 15.8; p=0.091). Role, cognitive, and social functioning were better in ePROm, with mean differences of 10.0 (95% CI 1.1, 18.9; p=0.028), 6.3 (1.1, 11.5; p=0.017), and 10.9 (3.9, 18.0; p=0.003), respectively. There was no difference in nausea/vomiting (0.5 - 6.2, 7.1; p=0.889), while fatigue was significantly better in ePROm (-8.4 -16.1, -0.6; p=0.034). Median time to first deterioration in Global QoL score was 3.9 months (95% CI 2.5, 13.9) in ePROm and 3.0 months (95% CI 1.6, 6.7) in UC (hazard ratio 0.73 95% CI 0.45, 1.17; p=0.159). Conclusions: ePROm systems, especially for symptom and SpO 2 tracking in HER2-positive MBC patients treated with T-DXd, are promising to enhance patient QoL. Clinical trial information: jRCTs031200387 .