Clinical trial for muscular dystrophy demonstrates safety of customized gene therapy

November 30, 2011

Researchers at the University of North Carolina at Chapel Hill have shown that it is safe to cut and paste together different viruses in an effort to create the ultimate vehicle for gene therapy. In a phase I clinical trial, the investigators found no side effects from using a "chimeric" virus to deliver replacement genes for an essential muscle protein in patients with muscular dystrophy.

"This trial demonstrates that is no longer limited by the we find in nature, and should usher in the next generation of viral delivery systems for human gene transfer," said senior study author R. Jude Samulski, PhD, professor of and director of the Gene Therapy Center at UNC. The study appears online in the Nov. 8, 2011 issue of the journal Molecular Therapy.

Through gene therapy, scientists treat diseases by correcting a patient's . Most of the time, this approach involves commandeering a natural system for infecting and introducing new genes into cells; thus, the virus. But even though there are lots of relatively innocuous viruses available for this purpose, none of them are perfectly suited for gene therapy.

Rather than rely on nature, Samulski and his colleagues decided to engineer their dream gene therapy virus in the laboratory. First they chose the adeno-associated virus or AAV, a small nonpathogenic virus that most humans are exposed to at some point in life. They then took their favorite attributes from different forms of AAV – such as AAV type 1's ability to sneak into muscle, and AAV type 2's safe track record – and combined them into one "chimeric" virus. In the first trial of this form of gene therapy, the investigators gave six boys with Duchenne (DMD) this new virus. An x-linked inherited disorder, DMD affects one in 4,000 newborn boys.

The virus was engineered to contain the dystrophin gene, which is missing in patients with muscular dystrophy and is the ultimate cause of the disease's progressive muscle weakness. The replacement genes were injected into the bicep in one arm and a placebo was injected into the other arm of each of the patients. The researchers were able to detect the new genes in all of the patients treated with the gene therapy, but no immunological response.

As they move on to the next phase of , Samulski says they are carefully considering how best to administer the gene therapy vectors to patients. Delivering enough replacement genes to a therapeutic effect could require larger doses of virus, which in turn could elicit an unwanted immune response. So the researchers are exploring a number of different options, including using a new high pressure technique developed by William J. Powers, MD, professor and chair of neurology at UNC, reported last July in the same journal, to get the virus into muscle at lower doses.

Explore further: Gene therapy success depends on ability to advance viral delivery vectors to commercialization

Related Stories

Gene therapy success depends on ability to advance viral delivery vectors to commercialization

May 18, 2011
Many gene therapy strategies designed to deliver a normal copy of a gene to cells carrying a disease-causing genetic mutation rely on a modified virus to transfer the gene product into affected tissues. One technology platform ...

Molecular delivery truck serves gene therapy cocktail

August 15, 2011
In a kind of molecular gymnastics, scientists at the University of North Carolina at Chapel Hill School of Medicine have devised a gene therapy cocktail that has the potential to treat some inherited diseases associated with ...

Recommended for you

Want to win at sports? Take a cue from these mighty mice

July 20, 2017
As student athletes hit training fields this summer to gain the competitive edge, a new study shows how the experiences of a tiny mouse can put them on the path to winning.

'Smart' robot technology could give stroke rehab a boost

July 19, 2017
Scientists say they have developed a "smart" robotic harness that might make it easier for people to learn to walk again after a stroke or spinal cord injury.

Engineered liver tissue expands after transplant

July 19, 2017
Many diseases, including cirrhosis and hepatitis, can lead to liver failure. More than 17,000 Americans suffering from these diseases are now waiting for liver transplants, but significantly fewer livers are available.

Lunatic Fringe gene plays key role in the renewable brain

July 19, 2017
The discovery that the brain can generate new cells - about 700 new neurons each day - has triggered investigations to uncover how this process is regulated. Researchers at Baylor College of Medicine and Jan and Dan Duncan ...

New animal models for hepatitis C could pave the way for a vaccine

July 19, 2017
They say that an ounce of prevention is worth a pound of cure. In the case of hepatitis C—a disease that affects nearly 71 million people worldwide, causing cirrhosis and liver cancer if left untreated—it might be worth ...

Omega-3 fatty acids fight inflammation via cannabinoids

July 18, 2017
Chemical compounds called cannabinoids are found in marijuana and also are produced naturally in the body from omega-3 fatty acids. A well-known cannabinoid in marijuana, tetrahydrocannabinol, is responsible for some of its ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.