Open-label, randomized pilot study to evaluate safety and tolerability of a novel dermal nanoparticulate imiquimod formulation in the treatment of actinic keratosis

Abstract

Objective: Actinic keratoses (AKs) are among the most common precancerous lesions in fair-skinned populations and are of considerable clinical relevance. Topical imiquimod has been established as an effective treatment option, although it is associated with local adverse events.

Aim: To assess the tolerability and safety of a novel nanoparticle-based imiquimod formulation (IMI.Gel) for the treatment of AK in comparison to the reference product Aldara. Secondary endpoints included efficacy, cosmetic outcomes, and patient-reported quality of life.

Methods: In an open-label, 1:1 randomized monocentric Phase I/II study patients with clinically diagnosed AK lesions were enrolled. Both groups received topical therapy three times per week over a 4-week period. Efficacy was evaluated at Week 8. In cases of persistent lesions, a second treatment cycle was administered. Follow-up was conducted over a 12-month period with three predefined study visits.

Results: A total of 81 patients were randomized (IMI.Gel n = 41; Aldara n = 40). The mean age was 72 years (range 44–89), and 78% of participants were male. No statistically significant differences were observed between the two treatment groups regarding tolerability (local skin reactions), safety (adverse events), or efficacy (lesion reduction). A second treatment cycle was performed in 73.0% of patients in the IMI.Gel group and 52.9% in the Aldara group. Complete response rates at 12 months were 48.4% for IMI.Gel and 48.5% for Aldara. Both groups showed a significant improvement in quality of life, as measured by a reduction in the Dermatology Life Quality Index of 1.12 points (IMI.Gel) and 1.02 points (Aldara) after 12 months.

Conclusion: The nanoparticle-based IMI.Gel proved to be a safe and tolerable alternative to the standard therapy with Aldara.

Trial Registration: EudraCT number: 2015-002203-28