Photodynamic Topical Antimicrobial Therapy for Infected Diabetic Foot Ulcers in Patients With Diabetes: A Case Series

Abstract

Diabetic foot ulcers (DFUs) are common, complex, costly complications, associated with frequent recurrences and increased morbidity and mortality. DFUs can be prevented and their healing can be mostly influenced by appropriately and aggressively managing any infection, but the role of antiseptic therapies in reducing healing time lacks sufficient evidence. Several therapeutic interventions have been developed based on the principles of photomedicine to overcome the issue of poor drug circulation in infected areas, with the aim of killing microbial agents while leaving the surrounding host cells unharmed. Such techniques use absorption of photons by specific chromophores. Among these, RLP068 is a tetracationic Zn(II) phthalocyanine derivative activated by exposure to red light, used as a topical treatment for superficial bacterial and fungal infections. The photoactivation of RLP068 results in the production of singlet oxygen and other reactive oxygen species, able to affect a range of cellular targets, including cell membrane and/or wall, cytoplasm, and cellular components, resulting in a rapid, broad range, bactericidal and fungicidal effect. The phase IIa study showed that photoactivated RPL068 is capable of inducing a dose-dependent reduction in total and pathogen microbial load in infected diabetic foot ulcers. In this article, a case series of 22 DFU treated with photoactivated RLP068 at 5 different centers in Italy is presented. Considering microbial agents reduction, ulcer healing facilitation, healing rate (9 DFUs out of 22), and amputation rate (only 1 case over 22), the decrease in the cost of DFU seems to be a point in favor of RLP068 and its cost-effectiveness.