First-Line Zongertinib in Advanced HER2-Mutant Non-Small-Cell Lung Cancer

Until recently, no first-line targeted treatment options were available for patients with human epidermal growth factor receptor 2 (HER2)-mutant non-small-cell lung cancer (NSCLC). Zongertinib is an oral, irreversible tyrosine kinase inhibitor that selectively inhibits HER2 while sparing wild-type epidermal growth factor receptor (EGFR), thereby minimizing associated toxic effects.

We conducted a phase 1a-1b, multicohort trial to assess zongertinib in patients with advanced or metastatic nonsquamous HER2-mutant NSCLC. Here, we evaluated zongertinib at a dose of 120 mg once daily in patients who had not previously received treatment (cohort 2). The primary end point was objective response as assessed by blinded independent central review. Secondary end points included duration of response and progression-free survival. In addition, zongertinib was evaluated in patients with active brain metastases (exploratory cohort 4).

In cohort 2, a total of 74 previously untreated patients received zongertinib at a dose of 120 mg. As of August 21, 2025, the percentage of patients with a confirmed objective response was 76% (95% confidence interval [CI], 65 to 84); the median duration of response was 15.2 months (95% CI, 9.8 to not evaluable), and the median progression-free survival was 14.4 months (95% CI, 11.1 to not evaluable). Adverse events of any grade occurred in 73 patients (99%), including events of grade 3 or higher in 33 patients (45%). Treatment-related adverse events occurred in 67 patients (91%), including events of grade 3 or higher in 14 patients (19%). In cohort 4, a total of 30 patients with active brain metastases received zongertinib at a dose of 120 mg; of these, 47% (95% CI, 30 to 64) had a confirmed intracranial objective response according to Response Assessment in Neuro-Oncology Brain Metastases criteria. In this cohort, treatment-related adverse events of grade 3 or higher occurred in 5 patients (17%).

Zongertinib showed sustained efficacy in previously untreated patients with advanced or metastatic HER2-mutant NSCLC. Treatment-related adverse events were predominantly low-grade. (Funded by Boehringer Ingelheim; Beamion LUNG-1 ClinicalTrials.gov number, NCT04886804.).