Experience of 11 years use of cidofovir in recurrent respiratory papillomatosis

Recurrent respiratory papillomatosis (RRP) is a viral induced disease, associated with exophytic epithelial lesions affecting the upper airways. Problem of treatment is the high recurrence of papilloma growth after surgical removal; therefore adjuvant therapy schemes have been established. Cidofovir was one of the agents used off-label in adjuvant therapy in the last years. However, there is ongoing discussion about the effectiveness and possible side effects. Aim of our study was to share our experience in treatment of RRP with cidofovir during the last 11 years. We analyzed all the data of patients treated for RRP at the Department for Phoniatrics of the Medical University of Graz between 1999 and 2011. 25 out of the 34 treated patients are at the moment under complete remission, in six patients partial remission could be achieved and two patients showed poor response to therapy, therefore the treatment with cidofovir was stopped. 21 patients received one cycle of monthly cidofovir, 11 patients received two and one patient three cycles of therapy. Number of procedures reached from one to six during each cycle. Average cumulative dose of one cycle was 79.7 mg (15-277.5 mg), in one patient 435 mg were used. One patient developed temporary, borderline neutropenia without symptoms. Despite the retrospective approach of this study with the limitation of several incomplete records, our results show promising long-term effects of adjuvant use of cidofovir. During this period, we did not observe any relevant side effects.