Overview
Hernexeos is approved by the U.S. Food and Drug Administration (FDA) for the treatment of adults with unresectable (cannot be removed by surgery) or metastatic (spread to other parts of the body) non-squamous non-small cell lung cancer (NSCLC) whose tumors have HER2 (ERBB2) tyrosine kinase domain activating mutations (changes), as detected by an FDA-authorized test. As of February 2026, this approval is under accelerated approval based on the observed response rate and duration of response; continued approval may depend on further verification of benefit in additional studies. Hernexeos is also known by its drug name, zongertinib.

This medication belongs to the class of kinase inhibitors. Scientists believe the drug works by blocking abnormal HER2 signals that cause cancer cells to grow, thereby helping to slow or stop the progression of lung cancer.

How do I take it?
Prescribing information states that Hernexeos is taken orally as a tablet once daily, with or without food, until disease progression or unacceptable toxicity occurs. The treatment schedule may be adjusted based on body weight, with a lower starting dose for individuals weighing less than 198 pounds. The medication should always be taken exactly as prescribed by a healthcare provider.

Side effects
Common side effects of Hernexeos include diarrhea, rash, hepatotoxicity (liver toxicity), fatigue, nausea, muscle or bone pain (musculoskeletal pain), and upper respiratory tract infection. Laboratory abnormalities such as decreased lymphocytes, increased liver enzymes (alanine aminotransferase), increased creatinine, increased gamma-glutamyl transferase, decreased potassium, and decreased neutrophils are also common.

Rare but serious side effects may include left ventricular dysfunction (a problem with how the heart pumps blood), interstitial lung disease or pneumonitis (inflammation of the lungs causing symptoms like cough, fever, and difficulty breathing), and embryo-fetal toxicity (risk of harm to an unborn baby).

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Label: HernexEos — Zongertinib Tablet, Film Coated — DailyMed