Gene therapy trial for glycogen storage disease produces remarkable results

A path-breaking gene therapy trial for glycogen storage disease has shown remarkable results

A groundbreaking, one-year clinical trial for a novel gene therapy treatment for glycogen storage disease (GSD) has shown remarkable results.

The rare and deadly genetic liver disorder, GSD type Ia, affects children from infancy through adulthood, causing dangerously low blood sugar levels and constant dependence on glucose consumption in the form of cornstarch every few hours for survival. If a cornstarch dose is missed, the disease can lead to seizures and even death.

One year after patient Jerrod Watts first received the GSD vaccine during a 30-minute infusion, he is completely off of cornstarch. In addition to totally stopping daily cornstarch consumption, Watts has experienced normal regulation of his blood glucose levels, weight loss, increased muscle strength, and marked improvement in his energy.

“The clinical trial is going better than expected. The therapy is transforming patients’ lives,” said lead investigator, Dr. David Weinstein, a pediatric endocrinologist and director of the Glycogen Storage Disease Program at Connecticut Children’s and UConn Health – the largest center in the world for the care and treatment of this condition.

The clinical trial initially tested the safety and dosage of the gene therapy for three patients with GSD Type Ia.

“One of the biggest reliefs from this gene therapy is I can now sleep through the night without worrying about dying in the middle of the night. I wake up 6 to 7 hours later with normal blood sugar,” said Watts

The gene therapy works by delivering a new copy of a gene to the liver via a naturally occurring virus. Administered through the patient’s bloodstream, the new copy replaces deficient sugar enzymes caused by the disease and jump starts the body’s glucose control.

Both Weinstein and Watts were surprised by Watts’ response to the gene therapy.

Prior to the treatment, Watts was consuming more than 400 grams of cornstarch per day. 

“The main thing I want to do is inspire hope. One of the biggest reliefs from this gene therapy is I can now sleep through the night without worrying about dying in the middle of the night. I wake up 6 to 7 hours later with normal blood sugar,” said Watts.

“I’m living, breathing proof that there is a light at the end of the tunnel with GSD. I’m a completely different person now that I was a year ago. I feel like I can live a normal life and I can do anything I want to do now,” added Watts.

In addition to Watts, two other clinical trial patients are seeing promising results on the lower cornstarch daily regimens. All three will participate in the next phase – a 4 year follow-up clinical trial study. In addition, three patients are enrolled in clinical trial testing a higher gene therapy dose.

If the patients are already coming off cornstarch and the labs are getting better, we just hope it will be even faster and more dramatic with the higher dose, said Dr. David Weinstein.