Long-term use of a new topical formulation containing piroxicam 0.8% and sunscreen: efficacy and tolerability on actinic keratosis. A proof of concept study

Abstract

Introduction: Cyclooxygenase (COX) 1 and 2 enzyme up-regulation is involved in the pathogenetic process of actinic keratosis (A.K.) and non-melanoma skin cancers. Diclofenac, a non-steroidal anti-inflammatory (N.S.A.I.D.) drug, is used as topical treatment of A.K. Piroxicam is a N.S.A.I.D. characterized by a high COX-1 inhibition activity.

Study aim: We conducted an 18 month exploratory open-label study on A.K., to assess the efficacy and tolerability of a new topical formulation of piroxicam and sunscreen in A.K. patients. Enrolled subjects applied a galenic formulation of piroxicam 0.8%, vehiculated in a topical product containing sun filters with high (50+) and broad spectrum (UVA) actions, twice a day for 6 months. Subjects were then followed up for additional 12 months. Thirty-eight subjects with a total of 69 A.K. lesions participated in the trial. The primary outcome was the evolution of the Actinic Keratosis Erythema Scale Atrophy (A.K.E.S.A) score assessing erythema, scale, and atrophy of a target A.K. lesion. Secondary outcomes were the percentage of treated lesions with complete (100%) or partial (≥75%) clearance and the evaluation skin tolerability.

Results: A.K.E.S.A. mean (S.D.) score at baseline was 7.5 (1.2). After 6 months of treatment, A.K.E.S.A. score decreased to 0.9 (1.1), a −88% reduction versus baseline. At the end of follow-up, A.K.E.S.A. score was 0.8 (1.2). A complete response was achieved in 38 of the 69 lesions (55%, 95% C.I.: 43% to 66%) and clearance was maintained 1 year post-treatment. A partial clearance was observed in 57 of 69 treated lesions (83%, 95% C.I.: 73% to 91%). Adverse events were limited to mild local irritation.

Conclusion: Our experience suggests that 6 month topical piroxicam 0.8% is efficacious and well tolerated in A.K. Clinical efficacy is maintained 1 year post-treatment. The main limitation of our study is that it was an open label non-controlled trial. Future controlled trials are warranted in order to compare the efficacy and tolerability of this topical piroxicam preparation with standard treatments in the management of A.K.

Keywords:

• Actinic keratosis
• Field cancerization
• Piroxicam

Transparency

Declaration of funding

This was a nonprofit trial. Publication support for this study was funded by Difa Cooper, Caronno Pertusella (VA), Italy.

Declaration of financial/other relationships

M.M. has disclosed that he was in private practice during the conduct and writing of this paper, but now has taken the position of Medical Director for Difa Cooper. He received no remuneration regarding this study. G.B., L.D., L.B., A.O., M.D.P., S.C., and E.C. have disclosed that they have no significant relationships with or financial interests in any commercial companies related to this study or article.

C.M.R.O. peer reviewers on this manuscript have received an honorarium from C.M.R.O. for their review work. Peer reviewer 1 has disclosed that he is a consultant to Gladerma, and is on the speakers’ bureau of Leo Pharma. Peer reviewers 2 and 3 have no relevant financial or other relationships to disclose.

Acknowledgments

We dedicate this work to the memory of Professor Sergio Chimenti for his outstanding activity devoted to dermatology and medical research, and his substantive contribution to this study.