Morphine and other pain medications that lead to addiction have been used for decades to treat pain associated with various forms of cancer. But University researchers recently found that gene therapy can serve a similar purpose by relieving cancer symptoms.
David Fink, chair of the Department of Neurology in the University’s Medical School, led a team of four other University researchers and three investigators from Diamyd Medical — a research firm based in Stockholm — to conduct a study that tested the potential implications of implementing a new treatment for patients suffering from immense pain as a result of various forms of cancer.
The study, which was published in the Annals of Neurology journal last week, showed that injections of the gene transfer vector — commonly referred to as NP2 — were agent was safe and that it improved current treatments, proving Fink’s hypothesis correct.
The purpose of using NP2 in the study was to test whether the pain experienced upon injection differed from the pain cancer patients felt after dosages of more common treatments, like morphine, were distributed.
The study’s subjects were given a herpes-based vector, Fink said. Samples of the herpes virus were injected into the vector, which was then administered the subjects. According to Fink, the herpes virus was explicitly chosen for this particular study.
“Cold sores are transmitted through skin contact,” Fink said. “In the same way, their injection tested for pain upon skin contact.”
The similarities between the transmission of the herpes virus and the transmission of the gene therapy as a mechanism of pain relief were meant to show the researchers whether the treatment is effective or not, Fink explained.
Using gene therapy as a mechanism to combat pain is a revolutionary discovery, Fink said.
“Initially, we thought gene therapy was only a way to correct abnormal genes,” Fink explained. “But now, therapies are very useful to express peptides as drugs in very local places in the central nervous system.”
There are three phases a treatment must go through before becoming available to consumers at a pharmacy, Fink said. In phase one, which was completed for this study, the safety of the drug is evaluated by a group of about 10-20 subjects, Fink said.
Next, larger studies are conducted to assess the effectiveness of the drug, pending it is proven to be acceptably safe in phase one. Finally, randomized, controlled, multicenter trials on large patient groups of up to 3,000 subjects assess how effective the drug is compared to current treatments. This phase determines whether a drug or therapeutic treatment goes to market, Fink said.
Susan Urba, a professor of hematology, oncology and otorhinolaryngology in the Medical School and one of the study’s researchers, wrote in an e-mail interview that when cancer patients first come to the University Hospital they are primarily seeking treatments for their disease, while researchers also work to improve their quality of life.
“They don’t realize that we can also offer innovative new treatments for control of their symptoms, too, which can potentially really benefit their quality of life,” she wrote.
According to Urba, the recent study has the potential to lead to future developments in the field.
“About 80 percent of patients with pain can be fairly easily treated with pain medications, although the other 20 percent are more challenging, and new approaches are needed …” Urba wrote.
She added that the researchers’ recently completed study will be used to assess the safety of further clinical trials.
“This study only looked at patients with cancer pain,” Urba wrote. “Similar vectors are being studied in neuropathic pain from nerve injuries and in pain resulting from diabetes.”