Pegfilgrastim is a long-acting granulocyte colony-stimulating factor formulation that has been approved for the prevention of febrile neutropenia. We herein report a case of interstitial pneumonia following administration of pegfilgrastim. A 65-year-old man with stage IV small-cell lung cancer was treated with carboplatin and etoposide as third-line chemotherapy. Pegfilgrastim was administered during the second cycle of chemotherapy. On the day after the administration of pegfilgrastim, interstitial pneumonia developed. The respiratory condition improved with pulse steroid therapy; however, the patient eventually succumbed to cancer progression. In conclusion, interstitial pneumonia due to pegfilgrastim is rare; however, physicians should be aware of the possibility of this adverse effect.
Keywords: interstitial lung disease; lung cancer; pegfilgrastim.