Regulatory Non-Clinical Photosafety Evaluation - An attempt to merge the FDA and EMEA Photosafety Testing Strategies.

Regul Toxicol Pharmacol. 2009 Jul 15; Colerangle JBPhotosafety testing has become a necessary component of drug development. Phototoxic effects to human skin can range from sunburn, premature skin aging, to life threatening skin cancer while phototoxic effects to the human eye can range from blurred vision to transient or permanent blindness. Phototoxic liabilities should be recognized early to avoid delays in drug development as they can have a strong impact on the safety and overall commercial success of a new drug product. Current guidance from the FDA and EMEA for photosafety testing varies widely among these regulatory agencies. While both guidance agree that only drug products that absorb light within the 290-700 nm range and distribute to the skin and/or eyes need to be tested, they do not specify what levels of either the drug product concentration in the skin/eyes or what molar absorbance would necessitate photosafety testing and when. The EMEA Concept paper published in 2008 does not provide any specific criteria for deciding whether photosafety testing is needed. Due to the lack of specified timing as to when photosafety testing should be conducted and what testing strategy should be pursued, the pharmaceutical companies should engage in dialogue with the regulatory agencies early in drug development to reach a consensus on these issues to avoid delays during drug development. This paper proposes a testing strategy that attempts to merge the testing proposals recommended by both regulatory agencies into a common strategy that meets the requirements of both regulatory agencies.