Pancytopenia During Osimertinib Treatment in a Patient with EGFR-Mutated Non-Small Cell Lung Cancer.

BACKGROUND

Osimertinib is an irreversible tyrosine kinase inhibitor approved for the treatment of metastatic epidermal growth factor receptor (EGFR)-mutated non-small cell lung cancer (NSCLC). In clinical trials, osimertinib has exhibited excellent activity and less toxicity compared to gefitinib, erlotinib and standard chemotherapy.

CASE PRESENTATION

Herein, we describe the case of a 69-year-old man who received first-line osimertinib for metastatic EGFR-mutated NSCLC. Suspected osimertinib-induced pancytopenia together with a partial treatment response was assessed after 10 days of therapy. Osimertinib was resumed at 40 mg daily a month later while the patient exhibited durable stable disease. No other adverse events occurred.

CONCLUSION

In the current case, first-line treatment with osimertinib at 80 mg daily in a patient with EGFR-mutated NSCLC resulted in severe pancytopenia and a rapid treatment response. Dose reduction to 40 mg daily resulted in excellent activity without any further adverse events. Osimertinib could be safely resumed at a reduced dose even after pancytopenia.