In a small new study, animals given large doses of gene therapies have died or experienced behavioral changes, Technology Review reports.
The University of Pennsylvania's James Wilson, who conducted the study notes that it's not that surprising, as a high dose of anything is likely to elicit side effects and toxicity. However, Tech Review adds that some gene therapies, particularly ones to treat muscular dystrophy, would need to give patients a hefty dose.
As they report in the journal Human Gene Therapy, Wilson and his colleagues gave three nonhuman primates and three piglets injection of an AAVhu68 vector of a human SMN transgene at a dose of 2x1014 genome copies per kilogram of body weight — a similar dose to that used in a spinal muscular atrophy trial. All of the animals, they report, experienced toxicity, including liver failure among the primates and an inability to walk among the piglets.
"I think the message is that for certain forms of gene therapy, and certain approaches to gene therapy, there may be situations in which we find dose-limiting toxicity," Wilson tells Tech Review.
Tech Review adds that Wilson was involved in the gene therapy trial in which Jesse Gelsinger died in 1999 due to a severe immune reaction.