Light Sciences Oncology Inc. of Seattle has made an agreement with the FDA on a special protocol assessment for a Phase III clinical trial. This will allow the company to compare its light infusion therapy product with another treatment for metastatic colorectal cancer in the liver. The device provides photodynamic therapy, by using LEDs to activate talaporfin sodium. Through production of singlet oxygenmolecules, the light-activated drug induces apoptosis in cells within a defined zone around the LED array.