Diclofenac Sodium 3% Gel for the Management of Actinic Keratosis: 10+ Years of Cumulative Evidence of Efficacy and Safety
May 2012 | Volume 11 | Issue 5 | Original Article | 600 | Copyright © May 2012
George M. Martin MDa and Eggert Stockfleth MD PhDb
aDermatology and Laser Center of Maui, Hawaii bSkin Cancer Center Charitè, Berlin, Germany
Abstract
Background: Diclofenac sodium 3% gel (Solaraze®) 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.
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.
J Drugs Dermatol.2012;11(5):600-608.
INTRODUCTION
Actinic keratosis (AK) is a chronic disease and part of a biologic continuum between photodamaged skin and invasive squamous cell carcinoma (SCC).1 Long-term management is required for AK because photodamage occurs over wide areas of sun-exposed skin, and new or recurrent lesions continue to develop on a background of field cancerization.1-3 Although destructive methods, such as cryotherapy and electrodessication and curettage (ED&C), are effective for isolated lesions, comprehensive clearance of widespread areas of clinical and subclinical lesions is best achieved with field-directed therapies, such as topical therapies or photodynamic therapy (PDT).3
Diclofenac sodium 3% gel (Solaraze®) offers an effective and well-tolerated topical option for treating multiple AK lesions. Pivotal phase 3 studies established that with 60 or 90 days of treatment, rates of complete clearance of existing and new lesions were significantly higher with diclofenac sodium 3% gel than with placebo.4,5 At 30 days following completion of a 90-day treatment course (0.5 mg twice daily), 50 percent of patients demonstrated complete clearance of target lesions and 47 percent demonstrated complete clearance of cumulative lesions.5 Pooled subgroup analyses of phase 3 data have reported significantly greater efficacy for diclofenac sodium 3% gel versus placebo for complete AK lesion clearance in the face and forehead 30 days post-treatment; no statistical difference was noted in the arms, hand and scalp, although the number of patients in those subgroups were small.6 Since the publication of the phase 3 pivotal trials of diclofenac sodium 3% gel, many clinical studies have assessed use of this therapy in a variety of body areas, special populations, and novel combinations. This article provides a comprehensive update on published data on use of diclofenac sodium 3% gel for AK (beyond the pivotal publications) since the product was approved for this indication in 2000.
