A New Era in HER2-Mutant Lung Cancer: Zongertinib Receives FDA Accelerated Approval

The US Food and Drug Administration (FDA) has granted accelerated approval for advanced or metastatic disease harboring an activating HER2 (ERBB2) tyrosine kinase domain (TKD) mutation following prior systemic treatment in patients with nonsquamous non-small cell lung cancer (NSCLC) ; the approved drug is the oral tyrosine kinase inhibitor zongertinib(marketed as Hernexeos, Boehringer Ingelheim Pharmaceuticals, Inc.). The approval was granted on 8 August 2025.

🔍 Who Is the Approval For?

Approximately 2-4% of patients with advanced non-small cell lung cancer (NSCLC) have a human epidermal growth factor receptor 2 (HER2) mutation. Until now, HER2-targeted treatment options were extremely limited, with FDA-approved treatment confined to antibody-drug conjugates such astrastuzumab deruxtecan (T-DXd; Enhertu). These treatments, however, do not work in every patient and carry risks of serious adverse effects, particularly complications such as interstitial lung disease.

Against this background, developingan effective, tolerable HER2-targeted treatment with the convenience of oral administrationhas become a major need for both patients and oncologists.

This approval covers adults whose tumor mutations have been identified using an FDA-approved test —specifically activating HER2 TKD mutations—and who:

• Have unresectable or metastatic disease;
• Have previously received systemic treatment, such as platinum-based chemotherapy;
• Have not received another HER2-targeted tyrosine kinase inhibitor or antibody-drug conjugate (ADC).

In addition, the Oncomine Dx Target Test molecular diagnostic assay was approved by the FDA to identify patients eligible for zongertinib treatment as a companion diagnostic test.

Zongertinibis a next-generation oral tyrosine kinase inhibitor (TKI) that targets HER2 mutations with high selectivity. Unlike existing HER2 inhibitors, it does not inhibit the epidermal growth factor receptor (EGFR), resulting in fewer common adverse effects such as rash and diarrhea.

📊 Efficacy Results from the Beamion LUNG-1 Study

The approval is based on data from Beamion LUNG-1 , an open-label, multicenter, multicohort clinical trial. The study used a Phase Ia/Ib design, and the full text of Beamion LUNG-1 was published on 28 April 2025 in theNew England Journal of Medicine.

Key endpoints: Objective response rate (ORR) and Duration of response (DOR) (blinded independent central review, RECIST v1.1).

1️⃣ Group with No Prior HER2-Targeted Treatment

• Number of patients: 71
• ORR: 75% (95% CI: 63–83%)
• Duration of response ≥6 months: 58%

2️⃣ Group Previously Treated with a HER2-Targeted ADC

• Number of patients: 34
• ORR: 44% (95% CI: 29–61%)
• Duration of response ≥6 months: 27%

💡 These data suggest that zongertinib may be effective even in patients who did not respond to another HER2-targeted treatment.

⚠️ Safety and Warnings

The zongertinib prescribing information includes warnings about the following risks:

• Liver toxicity (hepatotoxicity)
• Left ventricular dysfunction
• Interstitial lung disease / pneumonitis
• Embryo-fetal toxicity

💊 Recommended Dose

• <90 kg: 120 mg orally, 1 time daily
• ≥90 kg: 180 mg orally, 1 time daily

It may be taken with or without food. Treatment continues until disease progression or unacceptable adverse effects.

🩺 Why Does It Matter?

• Patients gain a treatment option that they can take at home instead of receiving intravenous infusions.
• It offers new hope for patients whose disease has progressed after platinum-based chemotherapy.
• It expands the range of HER2-targeted treatment options.

📌 Conclusion: FDA accelerated approval of zongertinib is an important milestone in the treatment of HER2-mutant NSCLC. Its high response rates and convenient oral administration give it the potential to change the treatment algorithm for this patient group.