The present invention relates to the pharmaceutical use of polyethylene glycol-(PEG)ylated IGF-I variants for the treatment, prevention and/or delay of progression of neuromuscular disorders, in particular amyotrophic lateral sclerosis (ALS). More specifically, the present invention relates to the use of a PEGylated IGF-I variant for the manufacture of a pharmaceutical composition for the treatment, prevention and/or delay of neuromuscular disorders, in particular ALS wherein the PEGylated IGF-I variant is characterized in that it is derived from the wild- type human IGF-I amino acid sequence (SEQ ID NO: 1) and carries one or two amino acid alterations at amino acid positions 27, 65 and 68 so that one or two of amino acids at positions 27, 65 and 68 is/are a polar amino acid but not lysine and PEG is attached to at least one lysine residue.
