Objective: To investigate the efficacy of intralesional cidofovir in the treatment of recurrent respiratory papillomatosis (RRP) in children.

Methods: Prospective observational study of four consecutive children with RRP treated at an academic tertiary children's hospital. Laryngo-bronchoscopy was performed at three- to five-weekly intervals. Photodocumentation was obtained and disease severity assessed using an anatomical RRP severity score. Surgical debulking of large papillomas was then performed, and cidofovir (5 mg/ml) injected into any remaining papillomas as well as submucosally at the sites of resected papillomas. The efficacy of cidofovir was assessed by the change in papilloma severity score over the course of the treatment.

Results: Complete disease remission was obtained in one patient, with a partial response seen in two others. One patient showed no significant response. The greatest beneficial effect was seen after the fourth cidofovir injection; however, two patients demonstrated a deterioration in severity scores after treatment was withheld at this point. Both responded well to further cidofovir injections. However, a clear plateau in the response to cidofovir was seen in all patients by the eighth injection.

Conclusion: Intralesional cidofovir may help control papilloma regrowth and reduce disease severity in many children with RRP. In most cases, cidofovir would appear to be less efficacious in causing disease eradication. There appears to be little evidence to support prolonged treatment regimes (i.e. more than eight treatments).