Safety and efficacy of 5% imiquimod cream for the treatment of skin dysplasia in high-risk renal transplant recipients: randomized, double-blind, placebo-controlled trial.

OBJECTIVE To evaluate the safety and efficacy of 5% imiquimod cream for cutaneous dysplasia in high-risk renal transplant recipients. DESIGN A randomized, blinded, placebo-controlled study comparing treated with control skin. SETTING A specialist organ transplant dermatology clinic. PATIENTS Twenty-one high-risk patients with skin cancer with comparable areas of clinically atypical skin on dorsal hands or forearms. INTERVENTIONS Imiquimod or placebo (randomly assigned) applied 3 times a week for 16 weeks to 1 dorsal hand or forearm, with 8 months of follow-up. At week 16, biopsy samples were collected from pre-assigned sites in the treatment and control areas and were examined for dysplasia. MAIN OUTCOME MEASURES The proportion of patients showing reduced numbers of viral and keratotic lesions and reduced histological severity of dysplasia in the treatment vs control areas at week 16, serum creatinine levels, and tumors developing in the study sites. RESULTS Fourteen patients receiving imiquimod and 6 receiving placebo completed the study. Seven patients using imiquimod (1 taking placebo) had reduced skin atypia, 7 using imiquimod (none taking placebo) had reduced viral warts, and 5 using imiquimod (1 taking placebo) showed less dysplasia histologically. In 1 year, fewer squamous skin tumors arose in imiquimod-treated skin than in control areas. Renal function was not adversely affected. CONCLUSIONS Topical 5% imiquimod cream seems to be safe on skin areas up to 60 cm2 in renal transplant recipients. It may be effective in reducing cutaneous dysplasia and the frequency of squamous tumors developing in high-risk patients. Larger studies are required to confirm these results.