Imiquimod 5% cream for the treatment of superficial and nodular basal cell carcinoma: randomized studies comparing low-frequency dosing with and without occlusion

Background Imiquimod 5% cream has been investigated for non-surgical treatment of superficial and nodular basal cell carcinoma (BCC) tumours. Objectives Two studies were conducted to examine the effect of occlusion at low dosing frequencies on the safety and efficacy of topical imiquimod 5% cream for the treatment of superficial and nodular BCC. Patients and methods Both open-label studies were conducted in Europe. Patients diagnosed with BCC were enrolled into either the superficial (93 patients) or nodular (90 patients) study, depending on the histological confirmation of the patient's tumour subtype. Patients were randomized to one of four groups to apply imiquimod 5% cream 2 or 3 days per week either with or without occlusion. Six weeks following a 6-week treatment period, the entire target tumour area was excised and histologically examined for evidence of residual tumour. Results In both studies, the highest histologically complete response rate was seen in the 3 days per week with occlusion groups, with complete response rates of 87% and 6 5% for the superficial and nodular studies, respectively. Occlusion did not have a statistically significant effect on response rate at either dosing frequency. Response rates for superficial and nodular BCC tumours treated 3 days per week without occlusion were 76% and 50%, respectively. Conclusions In the superficial study, the complete response rate of 87% in the 3 days per week with occlusion group was similar to that of daily and 5 days per week dosing without occlusion in a previous 12-week study and one study of daily dosing without occlusion for 6 weeks. All treatment groups had acceptable safety profiles in both studies. Occlusion did not have a statistically significant effect on efficacy for either superficial or nodular BCC tumours.