Clinical Development of Metal Complexes as Photosensitizers for Photodynamic Therapy of Cancer

Cancer has emerged over the last decades as one of the deadliest diseases in the world. Among the most commonly used techniques (i.e. surgery, immunotherapy, radiotherapy or chemotherapy), increasing attention has been devoted towards photodynamic therapy. However, the vast majority of clinically applied photosensitizers are not ideal and associated with several limitations including poor aqueous solubility, poor photostability and slow clearance from the body, causing photosensitivity. In an effort to overcome these drawbacks, much attention has been devoted towards the incorporation of a metal ion. Herein, the clinical development of metal-containing compounds including Purlytin® , Lutrin® /Antrin® , Photosens® , TOOKAD® soluble or TLD-1433 is critically reviewed.