Antibodies 2013, 2, 270-305; doi:10.3390/antib2020270 OPEN ACCESS antibodies ISSN 2073-4468 www.mdpi.com/journal/antibodies Review Antibody-Directed Phototherapy (ADP) Hayley Pye 1,3, Ioanna Stamati 1, Gokhan Yahioglu 1,2, M. Adil Butt 3 and Mahendra Deonarain 1,2,* 1 Faculty of Natural Sciences, Imperial College London, Exhibition Road, London, SW7 2AZ, UK 2 PhotoBiotics Ltd, Montague House, Chancery Lane, Thrapston, Northamptonshire, NN14 4LN, UK 3 National Medical Laser Centre, Charles Bell House, 67-73 Riding House Street, London, W1W 7EJ, UK * Author to whom correspondence should be addressed; E-Mail:
[email protected]. Received: 25 February 2013; in revised form: 3 April 2013 / Accepted: 4 April 2013 / Published: 25 April 2013 Abstract: Photodynamic therapy (PDT) is a clinically-approved but rather under-exploited treatment modality for cancer and pre-cancerous superficial lesions. It utilises a cold laser or LED to activate a photochemical reaction between a light activated drug (photosensitiser-drug) and oxygen to generate cytotoxic oxygen species. These free radical species damage cellular components leading to cell death. Despite its benefits, the complexity, limited potency and side effects of PDT have led to poor general usage. However, the research area is very active with an increasing understanding of PDT-related cell biology, photophysics and significant progress in molecular targeting of disease. Monoclonal antibody therapy is maturing and the next wave of antibody therapies includes antibody-drug conjugates (ADCs), which promise to be more potent and curable. These developments could lift antibody-directed phototherapy (ADP) to success. ADP promises to increase specificity and potency and improve drug pharmacokinetics, thus delivering better PDT drugs whilst retaining its other benefits.