Results from the Phase III REGION-I study evaluating ingenol mebutate gel 0.05% in the treatment of actinic keratosis (AK) have been presented at the 68th Annual Meeting of the American Academy of Dermatology (AAD).

REGION-I is a multicenter, parallel-group, double-blind study in which patients with actinic keratoses on non-head locations are randomised to PEP005 (ingenol mebutate) Gel 0.05% (n=117) or placebo (vehicle; n=118) once daily for two consecutive days.  The primary objective was to compare the efficacy, as measured by complete clearance of lesions, of PEP005 Gel with the vehicle.  Clearance was assessed on days 3, 8, 15, 29 and 57. 

The main results reported in the BioSpace abstract are as follows:

• Treatment with PEP005 Gel cleared AK lesions across all anatomical non-head sites at day 57, with complete clearance observed in 32 (27.4%) patients vs. 6 (5.1%) in the vehicle group (p=0.0001).

• For individual anatomical locations, complete clearance rates for active treatment were 0% (0/2) for the back, 16.0% (4/25) for the back of the hand, 16.7% (1/6) for legs, 25.3% (19/75) for the arms and 88.9% (8/9) for the chest.

• Partial clearance was seen in 52 (44.4%) of patients in the treatment group and 9 (7.6%) in the vehicle group (p<0.0001).

Adverse events were generally mild to moderate; those most commonly observed local skin reactions included erythema and flaking/scaling. A total of seven patients in the treatment group experienced pigmentation changes (four reported improvement and three reported worsening of pigmentation) and no patient experienced worsening of scarring. The most common side effects overall were application site irritation and pruritis.