LAUSR

Background: Standard therapies for patients with epidermal growth factor receptor-mutated (EGFRm) non-small cell lung cancer (NSCLC) that has progressed after treatment with third-generation EGFR tyrosine kinase inhibitors (TKIs) offer only limited benefit. Human epidermal growth factor receptor 3 (HER3) is often expressed in primary NSCLC tumors, and HER3 expression is commonly observed in patients with EGFR mutations. HER3-DXd is a novel antibody-drug conjugate composed of a human anti-HER3 monoclonal antibody (patritumab) linked to a topoisomerase I inhibitor payload via a tetrapeptide-based cleavable linker. HER3-DXd demonstrated efficacy and safety in a phase 1 study in patients with EGFRm NSCLC that progressed following an EGFR TKI and platinum-based chemotherapy (PBC) (U31402-A-U102; NCT03260491). In previously reported results from dose-escalation/expansion, HER3-DXd 5.6 mg/kg demonstrated a manageable safety profile and promising efficacy (confirmed objective response rate by blinded independent central review [BICR] of 39%, median duration of response of 7.0 months, and median progression-free survival of 8.2 months) in a subset of patients (n=44) with advanced EGFRm NSCLC that progressed after ≥1 line of PBC and a third-generation EGFR TKI. Trial Design: HERTHENA-Lung02 (NCT05338970) is a global, open-label, randomized, phase 3 trial evaluating the efficacy and safety of HER3-DXd vs PBC in patients (≈560) with metastatic or locally advanced nonsquamous NSCLC with an EGFR-activating mutation (exon 19 deletion or L858R) who have received 1 or 2 lines of EGFR TKI treatment including a third-generation EGFR TKI and had disease progression following treatment with a third-generation EGFR TKI. Patients are randomized 1:1 to receive either HER3-DXd 5.6 mg/kg every 3 weeks or 4 cycles of PBC containing pemetrexed (can be continued as maintenance) with cisplatin or carboplatin. Patients are stratified by prior third-generation EGFR TKI treatment (osimertinib vs other), line of prior third-generation EGFR TKI use (first vs second line), region (Asia vs rest of world), and presence of stable brain metastases (yes vs no). The primary endpoint is progression-free survival by BICR (per RECIST v1.1). The key secondary endpoint is overall survival. Other secondary endpoints include investigator-assessed progression-free survival, objective response rate, duration of response, clinical benefit rate, disease control rate, time to response (all assessed by investigator and BICR per RECIST 1.1), safety, and patient-reported outcomes. Enrollment began May 2022 and is ongoing, with sites in Asia, Australia, Europe, and North America. Citation Format: Balazs Halmos, Helena A. Yu, Yi-Long Wu, Makoto Nishio, Martin Reck, David Sternberg, Stephen Esker, Tony Mok. HERTHENA-Lung02: A randomized Phase 3 study of patritumab deruxtecan vs platinum-based chemotherapy in locally advanced or metastatic EGFR-mutated NSCLC after progression with a third-generation EGFR tyrosine kinase inhibitor [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr CT066.