A modified version of the virus that causes poliomyelitis shows great promise for treating brain tumors, researchers say. According to findings being presented today at a meeting of the American Society for Microbiology in Orlando, Fla., a poliovirus carrying a piece of the virus that causes the common cold eliminated tumors in the brains of mice.

Matthias Gromeier of Duke University and his colleagues began looking into this new therapy when they discovered that the molecule poliovirus binds to, CD155, is expressed in malignant gliomas, the most common type of brain tumor. They reasoned that CD155 would naturally home in on the tumors. But because poliovirus can cause disease in humans, the team first modified it by inserting a piece of rhinovirus DNA into the poliovirus. "The mixed polio/rhinovirus construct had very surprising properties," Gromeier reports. "It had lost its ability to cause poliomyelitis in humans but retained excellent killing potential for malignant glioma cells."

The team then administered a single dose of the treatment to mice harboring implanted brain tumors. Within days, the mice fully recovered, and pathological analyses of their brains revealed that the tumors had been eliminated. Whether the therapy will work in humans remains to be seen. But indications may come soon: the researchers note that a prototype of the recombinant virus is currently being prepared for clinical trials in patients with incurable brain tumors.