Final Analysis Results and Patient-Reported Outcomes From DESTINY-Lung02—A Dose-Blinded, Randomized, Phase 2 Study of Trastuzumab Deruxtecan in Patients With HER2-Mutant Metastatic NSCLC

Introduction: Trastuzumab deruxtecan (T-DXd) demonstrated strong and durable responses in patients with previously treated HER2 (ERBB2) mutant (HER2m) metastatic NSCLC (mNSCLC) in the DESTINY-Lung02 primary analysis (December 23, 2022, data cutoff). This final analysis evaluated T-DXd efficacy and safety after 8 additional months of follow-up, including clinically relevant subgroups and patient-reported outcomes. Methods: DESTINY-Lung02 was a randomized, dose-blinded, multicenter, phase 2 trial. Patients with previously treated HER2m mNSCLC were randomized 2:1 to receive T-DXd 5.4 or 6.4 mg/kg once every 3 weeks. Primary end point was confirmed objective response rate by blinded independent central review. Results: As of August 25, 2023, 102 and 50 patients had received T-DXd 5.4 or 6.4 mg/kg, respectively. Median follow-up (Q1–Q3) was 15.8 (8.2–20.7) months and 16.5 (9.4–20.8) months, respectively. Confirmed objective response rate (95% confidence interval) was 50.0% (51/102; 39.9%–60.1%) and 56.0% (28/50; 41.3%–70.0%), respectively. Safety profile was acceptable and generally manageable. Accordingly, median treatment duration (Q1–Q3) was 7.7 (3.7–14.4) months and 8.3 (2.8–13.1) months; drug-related grade 3 or higher treatment-emergent adverse events occurred in 39.6% (40/101) and 60.0% (30/50), with nausea most common (67.3% [68/101], 82.0% [41/50]). Adjudicated drug-related interstitial lung disease occurred in 14.9% (15/101) and 32.0% (16/50), mostly grade 1 or 2 with one grade 5 in each arm. Health-related quality of life was preserved for the duration of T-DXd treatment while sample size was sufficient for analysis, with no adverse effects on health-related quality of life observed at either dose. Conclusions: T-DXd demonstrated strong and durable responses at both doses, with no clinically significant changes in toxicity. The approved 5.4-mg/kg dose demonstrated a more favorable benefit-risk profile, including lower adjudicated drug-related interstitial lung disease incidence.