Low-dose 5-fluorouracil in combination with salicylic acid as a new lesion-directed option to treat topically actinic keratoses: histological and clinical study results

Abstract

Background Actinic keratoses (AKs) arise after chronic sun exposure. Because long‐term ultraviolet (UV) damage may induce proliferation of atypical keratinocytes, treatment of AKs is recommended. Objectives To compare 5‐fluorouracil 0·5%/salicylic acid 10·0% [low‐dose 5‐FU/SA (Actikerall^®)] with diclofenac 3% in hyaluronic acid (diclofenac HA) and vehicle for the treatment of AKs. Methods This was a randomized, placebo‐controlled, double‐blind, parallel‐group, multicentre trial. Patients received topical low‐dose 5‐FU/SA once daily, its vehicle or diclofenac HA twice daily for a maximum of 12 weeks. The final evaluation was at week 20. The primary objectives were to demonstrate the histological clearance rate of one predefined lesion. The secondary objectives were the improvement of treated lesions, tolerability and safety. Results There were 470 patients with 4–10 AK lesions each (grade I or II) on the face/forehead or bald scalp included in the study. Low‐dose 5‐FU/SA was superior to diclofenac HA (P < 0·01) and vehicle (P < 0·0001) for histological clearance of one representative lesion 8 weeks post‐treatment. In 72·0%, 59·1% and 44·8% of patients in the low‐dose 5‐FU/SA, diclofenac HA and vehicle groups, respectively, the week‐20 biopsy revealed no AKs. Significantly more lesions were cleared with low‐dose 5‐FU/SA (74·5%) compared with diclofenac HA (54·6%; P < 0·001) or vehicle (35·5%; P < 0·001). Low‐dose 5‐FU/SA was superior in terms of complete clinical clearance: 55·4%, vs. diclofenac HA (32·0%, P < 0·001) and vehicle (15·1%P < 0·001). Application‐site disorders (mainly burning and inflammation) were more frequent with low‐dose 5‐FU/SA but mainly of mild to moderate intensity. Conclusions Topical low‐dose 5‐FU/SA demonstrated higher histological and clinical clearance rates vs. diclofenac HA or vehicle. Low‐dose 5‐FU/SA is an effective lesion‐directed treatment for AKs.