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Efficacy Endpoints in Clinical Trials in Actinic Keratosis
Torsten Skov1, Eggert Stockfleth2, Rolf-Markus Szeimies3
1LEO Pharma A/S, Ballerup, Denmark. torsten.skov@leo-pharma.com.
Introduction:
Actinic keratosis is regarded as a chronic disease of the skin and, although fluctuating, is chronically progressive. Approval of new products for the treatment of actinic keratosis requires the use of a standard methodology in clinical trials which emphasize complete clearance of all actinic keratoses in a treatment field in a defined time span and the evaluation of long-term efficacy in terms of recurrence rate among completely cleared patients.
Methods:
Analysis of data from six previously published clinical trials in patients with actinic keratosis.
Results:
There was poor agreement over a period of 1 month in the complete clearance endpoint. This variation in assessment renders recurrence in cleared patients invalid as the estimate of long-term efficacy. Furthermore, complete clearance was shown to depend heavily on the number of baseline actinic keratoses.
Conclusion:
The main endpoints presently in use for the assessment of short- and long-term efficacy of actinic keratosis field-directed therapy, namely, complete clearance and recurrence rate, are obsolete and should be replaced by the percentage reduction in actinic keratosis count or the absolute actinic keratosis count.
Funding:
LEO Pharma A/S.
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