By Pat Anson, Editor
An experimental gene therapy reduces pain and other symptoms by over 50 percent in patients with diabetic peripheral neuropathy, according to a new study at Northwestern University.
Nearly 26 million people in the United States have diabetes and about half have some form of neuropathy, according to the American Diabetes Association. Diabetic peripheral neuropathy (DPN) causes nerves to send out abnormal signals. Patients feel pain or loss of feeling in their toes, feet, legs, hands and arms. It may also include a persistent burning, tingling or prickling sensation. The condition can lead to injuries, chronic foot ulcers and even amputations.
Keith Wenckowski, who has type-one diabetes, says it felt “like walking on glass” when he walked barefoot in sand.
Wenckowski and 83 other participants in the Northwestern study received two low doses of a non-viral gene therapy called VM202. They went to a clinic twice in a two-week period for a series of injections into their calf muscles and lower legs. Some received injections of a saline placebo, others a low dose of the therapy and others a higher dose.
"Those who received the therapy reported more than a 50 percent reduction in their symptoms and virtually no side effects," said Dr. Jack Kessler, lead author of the study. "Not only did it improve their pain, it also improved their ability to perceive a very, very light touch."
After three months, patients in the low-dose group experienced a significant reduction in pain compared to the placebo group. The effect persisted at six and nine months in the low-dose group.
"I can now go to a beach and walk on the sand without feeling like I am walking on glass," says Wenckowski, more than a year after receiving the therapy. "I am hoping the effects I am feeling do not cease."
VM202 contains the human hepatocyte growth factor (HGF) gene. Growth factor is a naturally occurring protein in the body that acts on nerve cell to keep them alive, healthy and functioning. Future studies will investigate if the therapy can actually regenerate damaged nerves and reverse the neuropathy.
Patients with the most extreme form of the DPN feel intense pain with a slight graze or touch. The pain can interfere with daily activities, sleep, mood and can diminish quality of life. Many drugs used to treat DPN, such as Neurontin and Lyrica, either don’t work or have unpleasant side effects.
"We are hoping that the treatment will increase the local production of hepatocyte growth factor to help regenerate nerves and grow new blood vessels and therefore reduce the pain," said Senda Ajroud-Driss, MD, an attending physician at Northwestern Memorial Hospital and an author of the study.
"We found that the patients who received the low dose had a better reduction in pain than the people who received the high dose or the placebo. Side effects were limited to injection site reaction."
The results of this Phase II, double-blind, placebo-controlled study are being published in the journal Annals of Clinical and Translation Neurology.A future, much larger Phase III study will soon be underway.
"Right now there is no medication that can reverse neuropathy," Kessler said. "Our goal is to develop a treatment. If we can show with more patients that this is a very real phenomenon, then we can show we have not only improved the symptoms of the disease, namely the pain, but we have actually improved function."