Clinical responses to Cidofovir applied topically to women with high grade vulval intraepithelial neoplasia

OBJECTIVES: Cidofovir is an acyclic nucleoside phosphonate, with broad spectrum anti-viral activity. It has previously been used in a number of clinical settings, including high grade intraepithelial disease in the cervix and low grade vulval disease. This pilot study was set up to assess whether Cidofovir might be useful in treating high grade vulval intraepithelial neoplasia. METHODS: Women with high grade non-cervical anogenital intraepithelial neoplasia were treated with a topical formulation of 1% Cidofovir in Unguentum Merck. Safety, side effects, clinical response and viral status were assessed. Clinical response was measured using symptoms, clinical (and photographic) appearance, viral status and histology. RESULTS: 12 women with high grade vulval, vaginal or perianal intraepithelial neoplasia were recruited, 10 of whom completed follow up. Diseased tissue underwent ulceration in the majority of cases, with no effect seen on neighbouring normal skin. Four women had complete regression of disease, with resolution of long standing symptoms as well as histological and viral clearance. Three women had a partial response. Two women did not respond, and one woman made a complete symptomatic response but was found to have invasive disease at final biopsy. CONCLUSION: These complete responses, in women with long standing disease, together with preservation of normal tissue, suggest that topical treatment with Cidofovir may have a place in the therapeutic armamentarium of high grade vulval intraepithelial neoplasia