Stepped-dose protocol of cidofovir therapy in recurrent respiratory papillomatosis in children

Objective: To evaluate a stepped-dose protocol for intralesional injection of cidofovir in children with recurrent respiratory papillomatosis (RRP). Design: Prospective, nonrandomized case series. Setting: Tertiary care children's hospital. Participants: Eleven children undergoing evaluation for RRP from June 1, 2000, through December 31, 2001. Intervention: Intralesional injection of cidofovir was performed after microlaryngoscopy and carbon dioxide laser treatment. Patients received 4 monthly injections at a concentration of 5 mg/mL and returned 1 month after the last injection for follow-up. Patients with recurrent or recalcitrant disease then started a series of 4 monthly injections at a concentration of 10 mg/mL. Outcome Measure: Papilloma stage (0-3) documented at multiple subsites by means of serial microlaryngoscopy. We calculated a severity score by summing the scores at all affected subsites. Results: The severity score decreased in each of the 11 patients during the course of therapy, from a mean ± SD of 13.7 ± 6.0 at enrollment to 2.1 ± 3.4 at 1-month follow-up. Six patients experienced complete resolution (stage 0) and 4 others had mild disease (stage, ≤5) after 4 treatments at the 5-mg/mL concentration. Five patients with residual or recurrent RRP subsequently started a series of 4 cidofovir treatments at a concentration of 10 mg/mL, with a mixed response. Conclusions: Intralesional injection of cidofovir seems to reduce the burden of disease in children with RRP. Patients with persistent or recurrent disease may benefit from an increased cidofovir concentration of 10 mg/mL, although some aggressive papillomatous disease remains refractory to cidofovir treatment.