Stem Cell Therapy Could Offer Cure for Type 1 Diabetes
A groundbreaking stem cell therapy offers hope for patients with Type 1 diabetes, enabling insulin independence for many.
By
Patrick Campbell
| Published on June 26, 2025
4 min read
Credit: Adobe Stock
A cutting-edge stem cell treatment has helped most participants with Type 1 diabetes (T1D) live without insulin injections for at least one year, according to new results from a clinical trial presented at the 2025 American Diabetes Association (ADA) Scientific Sessions in Chicago.
The therapy, zimislecel, formerly known as VX-880 and developed by Vertex Pharmaceuticals, uses lab-grown islet cells to restore the body’s ability to make its own insulin. The Phase 2 data, also published in the New England Journal of Medicine, marks one of the most promising advances in decades for people living with T1D.
Type 1 diabetes affects roughly 1.4 million Americans, according to the Centers for Disease Control and Prevention. There is currently no cure, and treatment relies on lifelong insulin therapy.
If zimislecel continues to show durable insulin independence, it could become the first functional cell-based therapy to change the course of T1D — not just manage it. For patients, it represents a glimpse of life without daily injections, pumps and constant glucose monitoring.
Most Participants Off Insulin After One Year
In the trial, 12 adults with T1D received a single infusion of zimislecel through the portal vein and were placed on standard immunosuppressive drugs to prevent rejection. One year later, 10 of the 12 patients (83%) were completely off insulin. All 12 had functioning islet cells, confirmed by detectable C-peptide levels, which were absent at the start of the study.
None of the participants experienced severe hypoglycemic events, a major risk for people with T1D who rely on insulin. Every participant had hemoglobin A1c levels under 7% — the recommended target for diabetes control — and spent more than 70% of their time in the target blood glucose range (70 to 180 milligrams per deciliter).
“It’s remarkable to see 12 out of 12 patients reach consensus targets for glycemic control and eliminate severe hypoglycemia,” said lead investigator Michael Rickels, M.D., professor at the University of Pennsylvania, in a news release. “This brings hope and confidence for a transformative treatment option for individuals with Type 1 diabetes in the not-so-distant future.”
While the results are promising, the therapy does carry risks, largely due to the use of immune-suppressing medications. Among 14 patients in the safety analysis, three developed neutropenia, or low white blood cell counts. One participant in Phase 2 died of cryptococcal meningitis, believed to be related to the immunosuppressive therapy. A separate death during Phase 1 was linked to the progression of preexisting dementia.
Despite these events, researchers and advocates believe the therapy’s potential outweighs the risks — especially for patients with hard-to-control diabetes who frequently experience severe lows or cannot reach glucose targets.
What’s Ahead for Zimislecel
The FORWARD study has now moved into Phase 3 and aims to enroll 50 patients by the end of 2025. Vertex also plans to begin a separate trial in adults with T1D who are already taking immunosuppressive drugs following kidney transplants.
“Stem cell therapy is showing tremendous promise in transforming Type 1 diabetes care,” said Marlon Pragnell, Ph.D., vice president of research and science at the ADA. “With advances in genetic engineering, these therapies may one day evade immune attack — eliminating the need for immunosuppressive drugs.”
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