It’s been about one year since we’ve had a major update from Vertex Pharmaceuticals, the biotech firm developing a futuristic therapy that could represent a cure for type 1 diabetes. Today, on the first day of the American Diabetes Association’s annual Scientific Sessions, Vertex released a fresh batch of results from its groundbreaking experiment.
Those results are remarkable: Vertex’s first two patients no longer need insulin injections to manage their blood sugar levels, and every other patient to receive the experimental treatment has shown impressive glycemic improvements.
The therapy, named VX-880, is a transplant of new pancreatic islet cells that have been grown in a laboratory from pluripotent stem cells. Those healthy new islet cells are surgically inserted into a patient’s portal vein, which delivers blood from the pancreas to the liver. Once in place, the new islet cells are able to sense blood glucose concentrations and secrete insulin on demand, just like healthy, natural islet cells.
Trevor W. Reichman, MD, PhD, the Surgical Director of Pancreas and Islet Cell Transplantation at the University of Toronto’s Ajmera Transplant Center, calls VX-880 “first-of-its-kind research [that] could be a gamechanger for the treatment of type 1 diabetes.”
We already knew that islet cell transplants work: Some lucky transplant recipients have enjoyed healthy blood sugar without the use of insulin for a decade or more. But until recently, doctors were able to harvest viable cells only from the pancreas of a deceased organ donor. Because such donor cells are so scarce, the procedure is performed only rarely, in cases of extreme need. (And in the United States, it’s not performed at all.)
In October 2021, Vertex shared the news that its very first patient, known only as Patient 1, had lowered his insulin usage by 91 percent. Before the transplant, he was using an average of 34 units of insulin per day. His A1C was 8.6 percent, above international glycemic targets for most adults, and he had zero detectable natural insulin production.
Ninety days after the procedure, Patient 1 had reduced his daily insulin usage to only 2.9 units. And despite using 91 percent less insulin, he also enjoyed a drop in A1C, down to a much healthier 7.2 percent. His insulin production had rebounded to the lower end of the normal range. The New York Times published an exclusive interview with Patient 1, who we learned was a 64-year-old man named Brian Shelton, stating that Shelton “may be the first person cured of type 1 diabetes.”
Though Shelton’s condition had undoubtedly improved, some people in the diabetes community bristled at the description of a “cure,” noting that both his A1C and his use of insulin seemed to confirm that he still had diabetes.
About six months later, though, the news got even better: Shelton had stopped using insulin injections entirely, and his A1C had improved to a perfectly healthy 5.2 percent. At this point, it seemed accurate to say that Shelton no longer had type 1 diabetes, though he requires immunosuppressive drugs to protect his new islet cells.
The Newest Results
We now have the details on six patients who have undergone the VX-880 procedure. Prior to their transplants, each of these volunteers had zero detectable natural insulin secretion, and each had a history of severe hypoglycemic events and hypoglycemia unawareness. These volunteers began the study with an average A1C of 8.13 percent.
All six patients have demonstrated:
Restored insulin secretion
Improved glycemic control
Reduced use of insulin injections
A complete absence of severe hypoglycemic events
There are now two patients who have completed one year since their transplant. Shelton has now remained insulin-free for a total of 21 months. Like Shelton, the second patient is off insulin injections entirely, and has an A1C measurement (6.0 percent) comfortably below the diagnostic threshold for diabetes. In recent months, both have achieved a time-in-range of 96 percent or greater.
Of the remaining patients, three have only completed 90 days, but “their trajectory is consistent” with the good results of the first two transplant recipients. A final patient had to discontinue the study “due to non-trial-related reasons,” according to Dr. Reichman.
Is It a ‘Cure’?
If VX-880 recipients don’t need insulin injections to achieve healthy blood glucose levels — presuming that their new transplanted islet cells continue to work equally well for the foreseeable future — can we say that the treatment is an actual cure for type 1 diabetes?
It’s an open question. Some in the diabetes research community are still reluctant to describe any solution that requires immunosuppressive drugs as a “cure.” VX-880 recipients will still need to take immunosuppressive drugs for the rest of their lives in order to protect their new islet cells. In his interview with the Times, Shelton reported that the antirejection drugs “cause him no side effects,” but the new data does show that some of the patients experienced mild side effects common to these medications.
In 2022, James Shapiro, MD, the surgeon that performed the world’s first islet cell transplants, explained to Diabetes Daily that “immunosuppressive drugs are the big barrier for why we don’t do large numbers of cell transplants today. The risks include increased risk of cancers, increased risk of life-threatening infections, side effects on the kidney, and they can also be toxic to the functioning of the transplanted cells and their ability to make insulin.”
Vertex is pursuing one or more therapies that aim to go beyond VX-880 by completely avoiding the need for immunotherapy. In March, Vertex announced that it would begin experiments on VX-264, which encapsulates lab-grown islet cells “in a channel array device designed to shield the cells from the body’s immune system.” Last year it also purchased a competitor, ViaCyte, that had begun experiments on islet cells gene-edited to escape detection from the immune system.
Whether or not you think of it as a “cure,” VX-880’s impressive results offer hope that scientists are getting closer to a treatment that can allow some patients with type 1 diabetes to achieve insulin independence. At the moment, there’s no telling how long it might take for VX-880 to win FDA approval, how much it would cost, or who would be eligible for the treatment, but the good results will allow Vertex to move full speed ahead with the next stage of its trials.