HER3-DXd (Patritumab Deruxtecan; U3-1402) in Combination With Osimertinib in Subjects With Locally Advanced or Metastatic EGFR-mutated Non-Small Cell Lung Cancer

Study Summary

This study includes a Dose Escalation Part to identify the recommended combination dose (RCD) and a Dose Expansion Part to further evaluate efficacy and safety. The primary objectives: Dose Escalation: To assess the safety and tolerability of HER3-DXd (patritumab deruxtecan; U3-1402) and osimertinib in subjects with locally advanced or metastatic non-small cell lung cancer (NSCLC) with an EGFR exon 19 deletion or L858R mutation with tumor progression after treatment with osimertinib, and to determine the recommended combination dose (RCD). Second-Line Dose Expansion Arm 1 and Arm 1b: To assess the preliminary antitumor activity of HER3-DXd and osimertinib in subjects with locally advanced or metastatic NSCLC with an EGFR exon 19 deletion or L858R mutation with tumor progression after treatment with osimertinib. Note: One or both of the study arms may open with one or two distinct dosing schedules. Second-Line Dose Expansion Arm 2: To assess the preliminary antitumor activity of HER3-DXd monotherapy in subjects with locally advanced or metastatic NSCLC with an EGFR exon 19 deletion or L858R mutation with tumor progression after treatment with osimertinib. First-Line Dose Expansion Cohorts 3, 4a, and 4b: To assess the preliminary antitumor activity of HER3-DXd and osimertinib in subjects with locally advanced or metastatic NSCLC with an EGFR exon 19 deletion or L858R mutation without prior systemic treatment for locally advanced or metastatic disease.