Adverse drug reactions are appreciably harmful or unpleasant reactions resulting from an intervention related to the use of medical products, which predicts hazard from future administration and warrants prevention or specific treatment, or alteration of the dosage regimen, or withdrawal of the product. Given medical case reports extracted from MEDLINE, the task is to classify whether the case report mentions the presence of any adverse drug reaction. Classify your answers into non-adverse drug event and adverse drug event.

Therefore, these patients might have to be treated with granulocyte colony-stimulating factor to be able to recover from severe neutropenia.
non-adverse drug event
The case report describes the condition of a patient who is suffering from severe neutropenia. The authors conclude that patients in the same condition may need to be treated with granulocyte colony-stimulating factor. There is no mention of adverse drug reaction in this case report, so the answer is "non-adverse drug event"..