A new diabetes treatment could free people from insulin injections

A new therapy for type 1 diabetes could nix the need for insulin injections.

Just a single infusion of lab-grown pancreatic cells let patients’ bodies make all the insulin they needed, scientists report June 20 in the New England Journal of Medicine. A year after treatment, 10 out of 12 participants no longer needed supplemental insulin.

“This is a landmark study ­— this cannot be overstated,” says Giacomo Lanzoni, a diabetes researcher at the University of Miami Miller School of Medicine who was not involved in the new work. These lab-grown cells can successfully treat diabetes, he says, and the technique to make them can be scaled up. That opens the door to restoring insulin production for many people with the disease.

Type 1 diabetes affects over 8 million people worldwide. It’s an autoimmune disease that pits a person’s immune system against the insulin-producing cells in their pancreas, destroying them. Insulin helps sugar pass from the blood to our cells, for energy; without it, sugar stays in the blood, starving cells. “People can’t survive without insulin,” says study coauthor Felicia Pagliuca, a cell biologist and senior vice president at Vertex Pharmaceuticals, the Boston-based company behind the new therapy.

That’s where injected insulin comes in. The drug has been around for more than 100 years, and tools such as continuous glucose monitors and insulin pumps help patients track blood sugar and adjust insulin levels. But these tools aren’t perfect. Our bodies tolerate a narrow Goldilocks zone of safe blood sugar levels. Too high and people can get kidney, nerve and eye damage. Too low and people can pass out, or worse.

“There’s really an urgent need for new therapies,” Pagliuca says. In 2023, the U.S. Food and Drug Administration approved a therapy using pancreatic cells from deceased donors intended to replace insulin-producing cells lost in people with type 1 diabetes. But the approach is limited by the number of available organ donors and the quality of their cells. Patients often need infusions from multiple donated pancreases, Pagliuca says.

To address these challenges, Vertex developed a method to grow pancreatic islet cells in the lab using human stem cells and a medley of nutrients and chemicals. These lab-grown islets, cell clusters that contain insulin-producing beta cells, don’t wind up in people’s pancreases. Instead, they settle in the liver, a location that seems to work well for them — and patients.

In a small clinical trial of 14 people with type 1 diabetes, doctors infused hundreds of millions of lab-made islet cells into participants’ veins. These cells “start working right from the get-go,” Pagliuca says, sensing blood sugar levels and producing insulin in response. After a full dose of the therapy, called zimislecel, 10 out of 12 participants once dependent on supplemental insulin no longer needed it — even a year after treatment. Two others reduced their insulin doses by up to 70 percent.

“Coming off insulin therapy is a remarkable achievement,” says Tom Donner, director of the Johns Hopkins Diabetes Center. Managing diabetes can be a huge psychological burden, he says. Alleviating the need for supplemental insulin could ease that load.

While patients in the new study generally tolerated the therapy well, Vertex scientists reported two unrelated deaths and a slew of side effects. One death stemmed from a surgical complication, Pagliuca says. The other was from a preexisting brain injury.

Side effects, which included diarrhea, headache, nausea and COVID-19 infection, were largely due to immunosuppressive drugs that prevent the body from attacking and rejecting the new islet cells. Patients will have to stay on these medications to protect the cells. 

“Immunosuppression is not a walk in the park,” Lanzoni says. It brings along all sorts of risks, including infection. Ideally, he’d like to see a diabetes cell therapy that doesn’t require long-term immunosuppression, something he and others in the field are working on.

Meanwhile, Vertex has expanded their study to include 50 total patients, almost all of whom have received their cell therapy dose. The researchers are hoping to have data from those patients and apply for regulatory approval for the therapy in 2026.