Zongertinib’s CNS Signal Expands the Conversation in HER2-Mutant Lung Cancer

The February 2026 expansion of zongertinib (Hernexeos; Boehringer Ingelheim) into the first-line setting gave clinicians a targeted option for adults with unresectable or metastatic nonsquamous non–small cell lung cancer (NSCLC) harboring HER2 (ERBB2) tyrosine kinase domain–activating mutations.¹ More recent attention, however, has shifted from systemic response alone to a harder question: Can this oral HER2-selective tyrosine kinase inhibitor (TKI) control disease in the brain?

Why Intracranial Activity Matters

Brain metastases are a major clinical problem in HER2-mutant NSCLC. In a US clinicogenomic analysis, 44% of patients with HER2-mutant metastatic NSCLC had brain metastases at baseline.² Central nervous system (CNS) progression can alter performance status, require corticosteroids or antiseizure therapy, and prompt radiation or surgery even when extracranial disease remains controlled.

Patients with active brain metastases have also frequently been underrepresented in clinical trials. Consequently, systemic objective response rates do not necessarily predict whether a drug reaches and controls intracranial disease.

A Dedicated Cohort Offers an Early Signal

The 2026 New England Journal of Medicine report from the phase 1a/1b Beamion LUNG-1 trial (NCT04886804) included an exploratory cohort of 30 patients with active brain metastases who received zongertinib 120 mg once daily. The confirmed intracranial objective response rate by Response Assessment in Neuro-Oncology Brain Metastases criteria was 47% (95% CI, 30%-64%). Median intracranial duration of response was 6.9 months, and median intracranial progression-free survival was 8.2 months.³

The findings were notable among patients without prior brain radiotherapy. Of 17 patients with centrally confirmed measurable CNS disease and no previous brain radiation, 59% had a confirmed intracranial response. Among 8 treatment-naïve patients in the active-brain-metastases cohort, the intracranial response rate was 50%.³

These results complement the trial’s first-line systemic cohort, in which 74 patients achieved a 76% confirmed objective response rate, with a median response duration of 15.2 months and median progression-free survival of 14.4 months.³ Together, the findings suggest that zongertinib has activity on both sides of the blood-brain barrier, although the intracranial evidence remains preliminary.

Pharmacists Can Help Navigate CNS Complexity

For oncology pharmacists, brain metastases add medication-management challenges beyond routine oral TKI counseling. New headache, weakness, confusion, speech changes, seizures, or worsening balance require rapid evaluation rather than attribution to fatigue or treatment alone. Pharmacists can also help distinguish cancer-related dyspnea or infection from interstitial lung disease/pneumonitis, a labeled warning for zongertinib.⁴

Medication reconciliation is particularly important when neurologic supportive care is initiated. The prescribing information recommends avoiding strong CYP3A inducers when possible; this warrants close review of enzyme-inducing antiseizure drugs and other interacting therapies.⁴ Steroid plans, gastrointestinal prophylaxis, adherence, and transitions between inpatient, radiation oncology, and ambulatory care should also be coordinated to prevent duplication or abrupt discontinuation.

Patient education should include an after-hours escalation pathway and caregiver involvement, particularly when cognitive changes, impaired dexterity, or complex supportive medications could compromise safe self-administration of a once-daily oral therapy.

Promising, but Not Practice-Settling

The CNS findings should not be interpreted as a replacement for multidisciplinary assessment of surgery or stereotactic radiation. The cohort was small, exploratory, single-arm, and included patients with differing treatment and radiotherapy histories. Moreover, zongertinib’s indication remains under accelerated approval based on response rate and response durability.¹

The phase 3 Beamion LUNG-2 trial (NCT06151574) is comparing first-line zongertinib with pembrolizumab plus platinum-pemetrexed chemotherapy; enrollment is complete, with primary completion estimated for September 2026.⁵ That randomized evidence will better define zongertinib’s overall first-line benefit. For now, its early intracranial signal is clinically meaningful—and reinforces the pharmacist’s role in integrating targeted therapy with neurologic supportive care and local CNS treatment.

REFERENCES

1. FDA grants accelerated approval to zongertinib for unresectable or metastatic non-squamous non-small cell lung cancer. FDA. Published February 26, 2026. Accessed August 11, 2026. https://www.fda.gov/drugs/resources-information-approved-drugs/fda-grants-accelerated-approval-zongertinib-unresectable-or-metastatic-non-squamous-non-small-cell

2. Waliany S, Nagasaka M, Park L, et al. Real-World Prevalence, Treatment Patterns, and Outcomes for Patients With HER2 (ERBB2)-Mutant Metastatic Non-Small Cell Lung Cancer, From a US-Based Clinico-Genomic Database. Cancer Med. 2024;13(24):e70272. doi:10.1002/cam4.70272

3. Heymach JV, Yamamoto N, Girard N, et al. First-Line Zongertinib in Advanced HER2-Mutant Non-Small-Cell Lung Cancer. N Engl J Med. 2026;394(17):1675-1684. doi:10.1056/NEJMoa2516969

4. Hernexeos (zongertinib) tablets, for oral use. Prescribing information. Boehringer Ingelheim Pharmaceuticals, Inc; revised February 2026. Accessed August 11, 2026. https://www.accessdata.fda.gov/drugsatfda_docs/label/2026/219042s001lbl.pdf

5. ClinicalTrials.gov. Beamion LUNG-2: A study to test whether zongertinib helps people with advanced non-small cell lung cancer with HER2 mutations compared with standard treatment. Updated July 23, 2026. Accessed August 11, 2026. https://clinicaltrials.gov/study/NCT06151574