Fluorescent tumours in the clinic
Munich/Groningen/Penzberg – For ten years, the application of image-guided surgery with tumour-specific fluorescent dyes has been limited to animal studies, because no one could predict safety or biodistribution of such targeted dyes in patients. Now for the first time, a Dutch-German team of researchers has found a way to convince regulatory authorities that their fluorochromes are safe and can be tested on human subjects. In November, the team got the go-ahead for a Phase I study in breast cancer patients with the fluorochrome IR dye 800 CW (LI-COR Bioscience) coupled to the antibody drug Avastin (Roche).
“Our advantage is that we already have a lot of clinical data about the safety and biodistribution of the cancer therapeutic Avastin, which binds to VEGF produced by cancer cells,” said Werner Scheuer from Pharma Research & Early Development at Roche (Penzberg), who developed the antibody-flurochrome conjugates in cooperation with Vasilis Ntziachristos (TU Munich) and Go van Dam (Medical College Groningen). In the November issue of the Journal of Nuclear Medicine (52(11): 1778-1785), the authors provided evidence that their cancer imaging agent behaves in animals as Avastin does in humans. For proving safety in humans, they will use microdoses of the dye – 100 times lower than the lowest dose in which the cancer drug shows an effect. “We want to statistically prove that breast cancer patients benefit from image-guided surgery with targeted fluorochromes,” explains Ntziachristos. He has developed a camera system that can identify the tumour margins with seven times better resolution than a surgeon can with the naked eye. A pipeline of antibody-fluorochrome conjugates is already being tested in animals.