Plant-derived gel 'treats actinic keratosis in 3 days'

Ingenol mebutate is derived from the Euphorbia peplus plant, commonly known as petty spurge. The sap of the weed has traditionally been used to treat a variety of conditions, including cancerous and pre-cancerous skin lesions. It acts by stimulating apoptosis in cancer cells, causing cell death within hours of application.

Promising phase III results

A pooled analysis of 4 randomised, double-blind, phase III studies, published in the New England Journal of Medicine, compared topical ingenol mebutate with placebo for the treatment of actinic keratosis. Two studies recruited patients with lesions on the trunk or extremities (n=458) and two studies involved patients with facial or scalp lesions (n=547).

Patients applied ingenol mebutate gel or placebo once daily for 2 days to lesions on the trunk or extremities and for 3 days to facial or scalp lesions. Two different strengths of gel are used for application to different parts of the body: 0.015% for the face and scalp and 0.05% for the body.

From the pooled analysis of the skin and face studies, the percentage of patients with complete clearance at day 57 was higher among those treated with ingenol mebutate than among those treated with placebo: 42.2% vs 3.7%; p<0.001; with a number needed to treat (NNT) of 2.6.

A similar rate of complete clearance was observed with ingenol mebutate in the pooled analysis of the two trunk and extremity studies: 34.1% vs 4.7% for placebo; p<0.001; NNT=3.4.

Adverse reactions were more common in the treatment arms, with application-site reactions occurring most frequently - affecting 12.0% of patients in the ingenol group versus 2.6% of the placebo group. However, they were generally mild to moderate in intensity.

Unlike ingenol mebutate, current treatment options for actinic keratosis typically require application for weeks or months. Leo Pharma has submitted a marketing authorisation application in the EU for ingenol mebutate.

Other recent developments

Last year, Almirall launched Actikerall, a topical combination treatment for actinic keratosis containing salicylic acid (10%) and fluorouracil (0.5%). Another topical product, Ameluz (5-aminolevulic acid), was awarded marketing authorisation in January 2012 for treatment of the face and scalp.