Diclofenac Sodium 3% Gel for the Management of Actinic Keratosis: 10+ Years of Cumulative Evidence of Efficacy and Safety

Background: Diclofenac sodium 3% gel (Solaraze (R)) gained US approval for the treatment of actinic keratosis (AK) more than 10 years ago. Since the publication of the pivotal phase 3 studies, numerous clinical studies have assessed use of this therapy in a variety of body areas, special populations, and novel combinations. Objective: To provide a comprehensive update on clinical data and research on the use of diclofenac sodium 3% gel in AK. Methods: Review of the literature. Results: Accumulating evidence from preclinical research supports that the proposed mechanism of diclofenac sodium 3% gel may include cyclo-oxgenase 2 (COX-2) inhibition, inhibition of angiogenesis, and induction of apoptosis. A literature review identified 17 publications (beyond the 2 pivotal studies) on the use of diclofenac sodium 3% gel for AK. A phase 4 open-label study reported that 58 percent of patients achieved complete clearance of target lesions at the 30-day post-treatment assessment; among patients who were evaluable at 1-year post-treatment, sustained long-term clearance of AK lesions was observed. Active comparator studies demonstrated comparable efficacy of diclofenac sodium 3% gel with 5-fluorouracil 5% and imiquimod 5%. Publications on the efficacy of diclofenac sodium 3% gel for AK of the lip report complete clearance rates comparable to those reported for other body areas. Diclofenac sodium 3% gel has also demonstrated efficacy for clearing AK lesions in immunosuppressed populations. Sequential use of diclofenac sodium 3% gel with cryosurgery or photodynamic therapy has been investigated and may emerge as a useful approach for some patients. Conclusions: Diclofenac sodium 3% gel has a unique proposed mechanism of action in AK that may involve COX-2 inhibition, inhibition of angiogenesis, and induction of apoptosis. In the past decade, numerous clinical studies have demonstrated this topical therapy to be effective and well tolerated for the treatment of AK.