Imagine having to drink a solution of cornstarch and water every four hours to survive, and that missing a dose, even by 15 minutes, could lead to seizures and death. This is the reality for Rebecca Tarrence, who has glycogen storage disease type 1a (GSDIa), a rare genetic disease caused by the presence of two genetic changes on the same gene affecting glucose production.
People with GSDIa are born without the ability to make a liver enzyme needed to break down glycogen into glucose, so they experience very low blood sugar between meals, which can lead to hospitalization and in some cases, death.
“GSDIa is a genetic condition where these patients cannot go for periods of time without food,” said David Rodriguez-Buritica, MD, associate professor of genetics in the Department of Pediatrics at McGovern Medical School at UTHealth Houston. “Typically, we use glycogen during those times of fasting between meals to maintain levels of glucose in the blood, but these patients have a problem doing that. So as a result of that, they cannot fast and need to be on a continuous source of glucose.”
“I wasn’t diagnosed until I was 18 months old,” said Rebecca, who is now 18. “From there it was a game of trying to figure out how to treat me because there wasn’t a lot of research about it like there is now.”
For the first six years of her life, Rebecca experienced monthly hospitalizations until she was placed on cornstarch therapy, a common therapy for GSDIa patients. She mixes cornstarch with water and takes it five times a day, allowing her to maintain normal blood sugar levels.
Rebecca has now joined a clinical study, known as the Ba1ance Trial, to test the safety and tolerability of Moderna’s investigational medication mRNA-3745, which is being evaluated to see if it will help correct the effects of the genetic defect causing GSDIa.
The mRNA technology uses messenger ribonucleic acid (mRNA), an instructional molecule that naturally occurs in the body and carries information to cells. In this case, Moderna is researching whether using mRNA-3745 can instruct the body to make the protein that is missing in people with GSDIa.
“Here we’re giving patients with GSDIa the investigational therapy mRNA-3745, which will enter the liver and potentially produce the enzyme that they lack, which will hopefully allow for the glucose to be released from the liver so that the patient can fast for a longer period of time. That’s the goal of this investigational therapy,” said Rodriguez, the primary investigator of the study and a faculty member of The University of Texas MD Anderson Cancer Center UTHealth Houston Graduate School of Biomedical Sciences.
Rebecca was the second person in the world with GSDIa to receive mRNA-3745 through a single intravenous infusion via a small tube inserted into a vein in the arm.
