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

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.