Most stem cell headlines are about joints. The most clinically significant stem cell story of the past year is about a different organ: the pancreas. A therapy called zimislecel, made from stem cells that become insulin-producing islet cells, has restored insulin production in people with type 1 diabetes in early trials. This article covers the 2025-2026 results honestly, including the risks, and explains the distance between exciting trial data and an approved therapy patients can actually access.
10 of 12
full-dose trial patients were insulin-independent at one year in the June 2025 NEJM report
2
deaths reported in the same study, one linked to immunosuppression and one to preexisting disease progression
2026
when Vertex expects to file marketing applications for zimislecel, which remains investigational as of October 2026
Islet cells in the pancreas produce insulin, and in type 1 diabetes the immune system destroys them. For decades the only cell-based option was transplanting islets from donated human pancreases, an approach limited by scarce donors and the need for lifelong immunosuppression. Stem cell-derived islet therapy aims to grow fully functional islet cells in a laboratory from stem cells, then infuse them into a patient's liver through the portal vein. The therapy now called zimislecel, from Vertex Pharmaceuticals, is the best-studied example, and it is made from a single manufactured cell line rather than donated organs.
At the American Diabetes Association's 85th Scientific Sessions in June 2025, with results published in the New England Journal of Medicine, Vertex reported on the Phase 1/2 portion of its FORWARD-101 master trial. All 12 patients with at least one year of follow-up who received a full-dose single infusion reached the ADA-recommended targets of an HbA1c below 7 percent and more than 70 percent time in range. Ten of the 12 were insulin-independent at one year, and none had a severe hypoglycemic event after day 90. That is the strongest result this kind of therapy has shown in type 1 diabetes.
“All 12 patients in the Phase 1/2 portion of the FORWARD-101 trial who received a full-dose infusion of stem cell-derived islets reached the ADA-recommended HbA1c and time-in-range targets, and 10 of 12 were insulin-independent at one year.”
The same report described two deaths among study participants: one from cryptococcal meningitis, an infection associated with immunosuppression, and one from progression of a preexisting neurological condition. The investigators concluded the results show the therapy can restore physiologic islet function, and they were equally clear that patients in this program require immunosuppression, which carries its own significant risks. That is the honest context for headline results: impressive in a carefully selected trial population, with real trade-offs.
Zimislecel holds FDA Fast Track and Regenerative Medicine Advanced Therapy designations, and the pivotal Phase 3 portion of the study is underway in people with impaired hypoglycemic awareness and severe hypoglycemic events. Vertex has said it expects to make marketing applications to global regulators in 2026. As of October 2026 no application has been approved, which means the therapy remains investigational and is not available outside clinical trials. The master protocol is registered on ClinicalTrials.gov under NCT04786262.
“Zimislecel holds FDA Fast Track and Regenerative Medicine Advanced Therapy designations, its pivotal phase of study is underway, and it remains investigational as of October 2026.”
It is easy to hear a stem cell headline about diabetes and assume every stem cell story is like this one. The reality is the opposite. This therapy works through fully differentiated islet cells, manufactured at scale from one cell line, and infused to restore a missing hormone. That is fundamentally different from injecting a patient's own cells into a joint. The same discipline applies to both stories: ask which specific product was studied for which condition, check whether it is part of a registered trial, and never let one encouraging result stand in for approval or access.
Type 1 diabetes is closer to a stem cell-derived therapy than almost any other condition, and the 2025-2026 results are genuinely a milestone. But a milestone and a marketplace are different things. For now the therapy is investigational, it requires immunosuppression, and access is limited to trial sites. For people with type 1 diabetes watching this news, the honest takeaway is hopeful and patient: the field is moving, and the credible sources update this space year by year.
A note from the clinic
At Aloha Stem Cell in Honolulu we focus on autologous, injection-based regenerative care for joints, tendons, and soft tissue, and we are deliberately careful about which stem cell stories apply to which treatments. If you have questions about any stem cell news, from diabetes research to joint injections, our team will help you separate the milestone from the marketing. Call (808) 593-2525 or book a consultation.
Our team is happy to listen to your story, answer your questions, and help you decide whether a consultation makes sense. There is no pressure and no obligation.
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