Type 1 diabetes management is a lifelong job that can’t be eliminated by lifestyle changes or any currently available drugs or medical devices. Because there’s no cure and no simple way to treat this chronic disease, it’s easy to understand why people might get excited about an experimental stem cell therapy that appears to reverse the condition — even if it has worked for only a few months in a single patient.
The experimental treatment that has all the buzz right now is so early in development it doesn’t even have an official name — it’s just called VX-880. The company developing the drug, Vertex Pharmaceuticals, announced the initiation of the first human trials for this stem cell therapy in March. Then, in October, the company shared preliminary results from the first of 17 patients to be included in these trials.
All the patients in these trials have type 1 diabetes, an autoimmune disease that develops when the body attacks and destroys insulin-making islet cells in the pancreas. Insulin is a hormone that helps convert sugars in our bloodstream into energy that fuels our body. Without functional islet cells to make insulin, sugars rise to dangerously high levels in the bloodstream. To prevent this, people with type 1 diabetes have to regularly inject insulin to manage their blood sugar.
For the first patient in these VX-880 trials, 90 days of stem cell therapy dramatically reduced both blood sugar levels and the need for daily insulin shots, according to the preliminary results released by Vertex. Before starting treatment, this patient used 34 units of insulin daily and had an A1C level, which reflects average blood sugar levels over about three months, of 8.6 percent, indicating dangerously high blood sugar. After three months of stem cell therapy, the patient used 2.9 units of insulin daily and their A1C levels dropped to 7.2 percent, a level that still signifies diabetes but is improved.
“VX-880 is potentially game-changing therapy,” says John Buse, MD, PhD, the chief of endocrinology and the director of the Diabetes Center at the University of North Carolina School of Medicine in Chapel Hill.
But Dr. Buse, who has no connection to Vertex or these trials, also cautions that much longer trials with far more patients will be needed before we can really tell how safe or effective this therapy might be — or whether it would be appropriate to use for every patient who has type 1 diabetes.
Simon Heller, MD, a diabetes researcher and a clinical professor at the University of Sheffield in the U.K. with no connection to Vertex or the trials, agrees. “It has promise, but it should not be regarded as a likely treatment option, probably for some years,” Dr. Heller says.
This means it’s far too soon to ask your doctor about whether stem cell therapy might work for you or a loved one living with type 1 diabetes.
And even if this drug does one day reach the market, it’s unclear how easy it would be for you to access or afford it. Insurance might not cover the treatment, and copays might be steep if it is covered. Vertex has been criticized for selling medicines that cost several hundred thousand dollars annually, a practice the company defends as necessary to support research and development of new drugs.
“It will be very expensive to start with I’d guess,” says Heller, who has received research funding and consulting fees from companies that sell drugs and devices to treat diabetes.
Making Islet Cells
Early work on VX-880 began more than a decade ago with a basic question: Could scientists find a way to replace dysfunctional islet cells in the pancreas with cells capable of making insulin?
Scientists thought embryonic stem cells might be the answer because they can in theory be transformed into any type of human cell in a lab. Researchers working to eradicate type 1 diabetes spent years fine-tuning a process to convert embryonic stem cells into functional islet cells. This work is complex because investigators needed to figure out how islet cells were created naturally inside the pancreas, then sort out how to program embryonic stem cells to grow into islet cells in the lab, a process that’s unique for every type of cell in the body.
Stem cell therapies involve replacing diseased or dysfunctional cells with healthy ones. All these lab experiments eventually led to VX-880, an infusion of replacement islet cells derived from embryonic stem cells. This is not only a potential breakthrough in the treatment of type 1 diabetes, it’s also one of the first practical demonstrations that embryonic stem cells might indeed be used to make treatments that replace dysfunctional cells — in this case islet cells in the pancreas, says one of the scientists who developed the drug, Doug Melton, PhD, the codirector of the Harvard Stem Cell Institute in Cambridge, Massachusetts, and an investigator at the Howard Hughes Medical Institute in Chevy Chase, Maryland.
Unlike other treatments for type 1 diabetes, VX-880 gives patients functional islet cells so they can make their own insulin, giving them enough of this hormone to regulate their blood sugar. In theory, this could mean people with type 1 diabetes no longer need to check their blood sugar levels and inject insulin several times a day to stay in a healthy range.
‘Factory to Make Their Own Insulin’
If this experimental drug lives up to its early promise, the infused replacement islet cells would “provide the patient with the natural factory to make their own insulin,” Dr. Melton said in a statement released by the Harvard Stem Cell Institute in October after preliminary results from tests in one patient came out.
One wrinkle to this approach is that patients would also need to take immunosuppressants — the same medicines given to people who receive organ donations — to stop the body from rejecting the new islet cells. Patients would potentially require lifelong therapy with both VX-880 and immunosuppressants. Long-term risks of immunosuppressants include susceptibility to serious infections, according to the Cleveland Clinic.
Scientists are also studying how to use what’s known as encapsulated islet cells (a different form of cells than those used in VX-880) that are surrounded by a membrane that helps prevent the body from mounting an immune system attack to reject them. These encapsulated islet cells have the potential to be used without immunosuppressants, said Bastiano Sanna, PhD, the executive vice president and chief of cell and genetic therapies at Vertex, in the statement released by the company with its preliminary trial results.
For now, however, any optimism about the potential to eradicate type 1 diabetes needs to be tempered by the reality that we know how well VX-880 works only in a single patient for a handful of months, says Heller.
One big unanswered question at this point is whether this experimental stem cell therapy can safely and reliably provide the body with working islet cells that can ramp up and scale back insulin production so that levels of the hormone rise and fall in concert with the amount of sugars circulating in the bloodstream, Heller notes. This process of detecting how much insulin is needed is crucial for helping to maintain healthy blood sugar levels over time.
“With just one person it is much too early to say whether this will turn out to be a realistic treatment, but it might,” Heller says. “We really need to see the results of a trial involving a largish number of patients for a time longer than 90 days.”