We created the final bill of "Intravenous cyclophosphamide (IVCY) for the treatment of rheumatic disease of children in general" in order to get approval for the off-label use of IVCY from the Study Group on Pediatric Drug Therapy. As a result, this study group approved IVCY's off-label use in children via public applications. We could create IVCY regimen specific for Japanese children independently of the efficacy, dosage, and administration applied in Germany, which at the time of application was the only country in Europe and the USA where IVCY was approved. Later, its use in adults was given approval through public applications after being fully reviewed by the Study Group on Unapproved and Off-label Drugs of High Medical Need. Consequently, IVCY is now available for the treatment of both childhood and adult rheumatic diseases in general.