Among preparations now in clinical use are PEG-asparaginase for treating leukemia, PEGylated interferons for hepatitis C, PEGylated granulocyte colony-stimulating factor for neutropenia, a PEGylated liposomal doxyrubicin for chemotherapy, and a PEGylated antisense oligonucleotide for macular degeneration. The gene discussed is CSF3; the disease is neutropenia.