Objective:

To report a case demonstrating the efficacy of amivantamab combined with chemotherapy in a patient with an uncommon EGFR G719A mutation, which is often associated with limited treatment options, and extensive visceral metastases.

Key Findings:

• Marked regression of lung mass, hepatic and brain metastases, and resolution of ascites observed in follow-up imaging, indicating a significant therapeutic response.
• Patient's performance status improved, and the response remained durable for over nine months, suggesting long-term benefits of the treatment.
• Manageable side effects included grade 1–2 skin rash and stomatitis, indicating tolerability of the treatment.

Interpretation:

This case highlights the potential of amivantamab-based combination therapy as a salvage option for patients with uncommon EGFR mutations and extensive metastases, suggesting a need for further exploration in clinical settings.

Limitations:

• This is a single case study, limiting generalizability and necessitating caution in interpreting results.
• Further studies are warranted to confirm findings in larger populations and to explore the efficacy of amivantamab in diverse patient cohorts.

Conclusion:

The case demonstrates a durable, near-complete response to amivantamab combined with chemotherapy in a high-risk patient.