Clinical Activity of Pan-HER Inhibitors Against HER2-Mutant Lung Adenocarcinoma

Area of Science:

• Oncology
• Genetics
• Pharmacology

Background:

• HER2 mutations are uncommon in non-small-cell lung cancer (NSCLC), typically occurring in 2-4% of cases.
• These mutations are often mutually exclusive with other known genetic alterations in lung cancer.
• Identifying HER2 mutations is crucial for targeted therapy selection.

Purpose of the Study:

• To determine the frequency and characteristics of HER2 mutations in a Korean cohort of lung adenocarcinoma patients.
• To evaluate the efficacy of pan-HER inhibitors (poziotinib and afatinib) in patients with HER2-mutant lung cancer.
• To describe the clinical features and outcomes of patients with HER2-mutant non-small-cell lung cancer.

Main Methods:

• A cohort of 360 lung adenocarcinoma patients from four Korean institutions were screened.
• Direct sequencing and next-generation sequencing were used to identify HER2 mutations.
• Patients with identified HER2 mutations received oral pan-HER inhibitors (poziotinib or afatinib).

Main Results:

• HER2 mutations were identified in 29 out of 129 patients (8.1%) analyzed by next-generation sequencing.
• The majority of patients with HER2 mutations were female (58.6%), never-smokers (70.0%), and had stage IV disease (55.2%).
• The most frequent HER2 mutation was c.2326_2327insTGT in exon 20 (48.3%); partial responses were observed in three patients treated with poziotinib or afatinib.

Conclusions:

• HER2 mutations occur at a notable frequency (8.1%) in Korean lung adenocarcinoma patients lacking other driver mutations.
• The observed responses to poziotinib and afatinib suggest potential therapeutic benefit for this patient subgroup.
• Further clinical studies are warranted to explore the efficacy of HER2-targeted therapies in HER2-mutant lung cancer.