The primary efficacy endpoint was the proportion of subjects in each treatment group with Complete Clearance (having no clinically visible actinic keratosis lesions in the 25 cm2 contiguous treatment area at the 8-week post-treatment visit) of AK lesions. The secondary efficacy endpoints were the Partial Clearance rates, defined as the proportion of subjects with at least a 75% reduction in the number of AK lesions counted at Baseline at the end-of-treatment visit (Week 16, EOT) and at the 8 weeks post-treatment visit/test-of-cure (Week 24, TOC), and the proportion of subjects with Complete Clearance of AK lesions at the end-of-treatment (Week 16, EOT) visit.