University of Michigan to develop novel therapy for neuropathic pain

Researchers from the University of Michigan Department of Neurology have received a $1.8 million dollar grant to develop a novel therapy for neuropathic pain, a difficult to treat condition in which patients experience pain because of damage to nerve without obvious tissue injury.

In previously published studies, these investigators have found that gene transfer to sensory nerves using a modified herpes simplex virus-based vector effectively reduced pain-related behaviors in rodents with nerve damage caused by trauma or diabetes. A gene transfer vector is an agent used to carry genes into cells.

The newly awarded grant from the Department of Veterans Affairs will allow the investigators to produce and certify a human grade vector that will then be tested in patients with pain from nerve damage resulting from diabetes.

"This grant will allow us to take the critical step in translating laboratory findings into human therapy," says principal investigator David Fink, M.D., Robert Brear professor and chair of the Department of Neurology. Fink is also a staff neurologist at the VA Ann Arbor Healthcare System.

Fink and his collaborators have previously demonstrated that gene transfer vectors created from recombinant crippled herpes simplex viruses can be used to deliver genes to sensory nerves from application in the skin.

Fink is directing a phase 1 human trial on the first such vector carrying the gene for human preproenkephalin in patients with intractable pain from cancer. The second trial will test a vector carrying the gene for glutamic acid decarboxylase that has proven to be particularly effective in animal models of neuropathic pain.

"We are very excited to receive this grant" says co-investigator Marina Mata, M.D., also a professor of Neurology.

"We routinely create new vectors and produce them in the laboratory for animal studies, but in order to have a vector that is approved for human use requires a series of extraordinarily expensive steps. This grant should allow us to begin the human trial in patients with painful diabetic neuropathy within two years."

Construction of the vector will be carried out under contract by Diamyd, Inc. of Pittsburgh, PA. Diamyd is funding the phase 1 trial of the preproenkephalin vector, and has licensed the patents to the vector technology.

The researchers believe that the use of HSV vectors holds promise not only for the treatment of pain but also ultimately for the treatment of peripheral neuropathy itself.