Treatment of severe laryngeal papillomatosis with intralesional injections of cidofovir [(S)-1-(3-hydroxy-2-phosphonylmethoxypropyl)cytosine].

Respiratory papillomatosis is a rare and often severe disease, usually localized in the larynx. It may cause respiratory distress and even life-threatening obstruction of the airways. Treatment is generally based on the evaporation of the lesions with a CO2 laser, but microsurgery, cytotoxic and/or cytostatic drugs, interferons, and vaccines are also used. Cidofovir [(S)-1-(3-hydroxy-2-phosphonylmethoxypropyl)cytosine] (HPMPC) was shown to suppress the growth of tumors induced by rabbit papillomavirus as well as human papillomavirus (HPV). The efficacy of cidofovir was assessed in 17 patients with severe respiratory papillomatosis. Cidofovir at a concentration of 2.5 mg/ml was injected directly in the different laryngeal papillomatous lesions during microlaryngoscopy under general anesthesia. Biopsies were taken before the treatment was started both for anatomopathology and viral typing. HPMPC kinetics in serum was monitored in three patients, the drug levels being determined by high-performance liquid chromatography. Complete disappearance of the papillomatosis was observed in 14 patients. Four patients relapsed and were successfully treated again with cidofovir. Of the three remaining patients, one progressed while under treatment with cidofovir, after an initial marked response. One patient had a partial remission and remained stable for more than 1 year after the last injection. He had a very aggressive and extensive disease originally. Finally, one patient was lost to follow-up after four injections. Intratumoral injections of cidofovir for the treatment of severe laryngeal papillomatosis is a powerful new therapeutic approach for this disease. Treatment was well tolerated, and no significant side effects were noted.