consider diabetic dogs as the perfect preclinical model. Also, the experts say if we can get the insulin production in these dogs with gene therapy and are successful, that we are over the major hurdle.”
Sollinger’s closest collaborator on the project to date is Insulete chief scientist Tausif Alam. Sollinger recruited Alam to the UW from the University of Texas Southwestern Medical Center more than 20 years ago, and the two worked closely together for years prior to Insulete’s launch.
Around the time that Sollinger realized pancreas transplants weren’t going to be the way to make a major impact in how Type 1 diabetes is treated, he created a list of criteria that any new treatment must meet.
“The cure has to be available for every diabetic,” he says. “The cure has to be affordable, and simple: It cannot be associated with a major operative procedure. And the cure cannot be associated with the patient having to take concomitant drugs, such as immunosuppressants, which have significant side effects.”
To create their would-be cure, Alam, Sollinger, and their team constructed tiny “minicircles” of DNA that a combine a gene for insulin with a sequence that switches the insulin gene on when glucose levels rise. (The researchers patented that so-called glucose-inducible response element with help from the Wisconsin Alumni Research Foundation.)
Another step was deciding which organ would be the best to target with the therapy. Sollinger says that the liver made the most sense because it shares a number of enzymes with the pancreas, and the two organs develop from the same part of the embryo. What’s more, he says, “it’s known in gene therapy that the liver is an organ that is very receptive to taking up genes.”
“That has been a very good choice,” he says. “As the science progressed, everybody said, ‘Oh yeah, [the liver] is the right way to do it, obviously.’ We don’t have a lot of competitors, but the people who are doing it are using the liver as a target organ.”
Sollinger says some of the researchers around the world working to develop therapies similar to Insulete’s include Roy Calne at the National University of Singapore, Matthias Elsner at Hannover Medical School, Ann Simpson at the University of Technology Sydney, and Peter Thule at Emory University. Another leading researcher is Stanford University’s Maria Grazia Roncarolo.
Insulete, which earlier this year raised $300,000 from investors and brought on Jay Handy—himself a diabetic—to serve as CEO, isn’t quite sure “what the end game will look like” in terms of commercialization, Sollinger says. He says that being acquired by a big drug company is one future possibility, but that for now the startup is just trying to put one foot in front of the other.
“The burden of proof is on us,” he says. “We have had discussions with several large pharma firms who have animal healthcare subsidiaries, and they are very interested. But we have to get the dogs cured first.”
Of course the real question is whether Insulete’s treatment can cure humans without dangerous side effects, and numerous once-promising gene therapies have failed when they’ve reached that test. For his part, Sollinger says that gene therapy will “dominate medicine” over the next 20 years. Only time and data will tell if his prediction proves to be right.
