Evaluation of the efficacy and tolerability of 0.5% fluorouracil cream and 5% fluorouracil cream applied to each side of the face in patients with actinic keratosis

Background: A new 0.5% fluorouracil cream has been developed that provides an alternative to the more highly concentrated topical formulations of fluorouracil that are currently available. Objective: This was a comparison of the tolerability and efficacy of the 0.5% and 5% fluorouracil creams in the treatment of actinic keratosis (AK). Methods: During this single-blind, randomized study, patients with greater than or equal to6 AK lesions were treated for 4 weeks with the 0.5% (once daily) and 5% (twice daily) fluorouracil creams applied to opposite sides of the face. After the end of treatment, patients were followed for an additional 4 weeks. Efficacy variables included absolute and percent reductions in AK lesions from baseline and total clearance of AK lesions. A questionnaire was used to evaluate patients' treatment preferences. Tolerability was evaluated through continuous monitoring of adverse events. Results: Treatment with 0.5% fluorouracil cream reduced the number of AK lesions from 11.3 at baseline to 2.5 at the end of the 4-week follow-up phase, compared with a reduction from 10.3 to 4.2 lesions after treatment with 5% fluorouracil cream. The reduction was significantly greater with the 0.5% cream compared with the 5% cream (P = 0.044). The 0.5% cream was as effective as the 5% cream in terms of the percent reduction in AK lesions from baseline (67% and 47%, respectively) and in achieving total clearance of AK lesions (both treatments, similar to43% of patients). Both treatments were associated with similar degrees of investigator-rated irritation;, however, patients preferred the 0.5% cream because they felt it was more tolerable (P = 0.003), easier to apply, and had a once-daily application schedule. Although all patients experienced facial irritation in association with both creams, fewer patients treated with the 0.5% cream reported symptoms of facial irritation. Conclusions: In this study, 0.5% fluorouracil cream once daily was at least as effective as 5% fluorouracil cream twice daily in terms of the percent reduction in AK lesions and total clearance of AK lesions; it was more effective than the 5% cream in reducing the absolute number of AK lesions from baseline. Patients preferred the 0.5% cream to the 5% cream.