HER2-Mediated Internalization of Cytotoxic Agents in ERBB2 Amplified or Mutant Lung Cancers

Area of Science:

• Oncology
• Molecular Biology
• Pharmacology

Background:

• HER2 (human epidermal growth factor receptor 2) is a receptor tyrosine kinase.
• Amplification or mutations in the ERBB2 gene lead to HER2 hyperactivation and tumor growth.
• Anti-HER2 antibody-drug conjugates (ADCs) are a targeted therapy approach.

Purpose of the Study:

• To investigate the mechanisms of HER2 internalization and ADC efficacy in lung cancer.
• To evaluate the impact of pan-HER inhibitors and ADC switching on treatment outcomes.
• To identify strategies for overcoming resistance to HER2-targeted therapies.

Main Methods:

• Utilized lung cancer cell lines and patient-derived xenograft models.
• Assessed HER2 ubiquitination, internalization, and endocytosis.
• Conducted a clinical trial of ado-trastuzumab emtansine (T-DM1).
• Investigated cotreatment with irreversible pan-HER inhibitors and ADC switching to trastuzumab deruxtecan (T-DXd).

Main Results:

• HER2 ubiquitination and internalization are critical for ADC efficacy, not HER2 overexpression.
• T-DM1 showed a 51% response rate in patients with ERBB2-altered lung cancer.
• Cotreatment with pan-HER inhibitors enhanced ADC internalization and efficacy.
• ADC switching to T-DXd achieved durable responses in a patient resistant to T-DM1.

Conclusions:

• HER2 ubiquitination and internalization are key determinants of anti-HER2 ADC effectiveness in lung cancer.
• Combination therapy with pan-HER inhibitors and ADC switching represent potential strategies for improving treatment outcomes.
• These findings may guide future clinical trials and expand ADC applications for HER2-activated lung cancers.