CHICAGO--Methylnaltrexone, an agent that blocks the side effects of morphine(Drug information on morphine) without interfering with pain relief, has been granted orphan drug status for use in patients with cancer pain.
"Orphan drug status is a big step toward bringing this important drug to a population of patients in need," said Michael Roizen, MD. He and his colleague Joseph Foss, MD, both of the University of Chicago, have done the preliminary animal and clinical testing of the drug, which is being developed in collaboration with UR Labs.
Methylnaltrexone was invented by the late University of Chicago pharmacologist Leon Goldberg, MD, PhD, to help a friend suffering from cancer. By attaching a methyl group to the naltrexone(Drug information on naltrexone) molecule, an anti-addiction agent, he altered the drug to prevent it from crossing the blood-brain barrier. As a result, it did not interfere with morphine's effects on pain, centered in the brain, but did prevent its others effects, such as nausea and constipation. Phase II/III trials of the orphan drug are planned this year.