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type1.science

Donor islet transplant (Lantidra / donislecel)

CellTrans, Inc.

A real cure, for a lucky few.

Insulin-producing islets from deceased donors, infused into the liver. In 2023 it became the first FDA-approved cell therapy for type 1 diabetes — a genuine milestone that can free some recipients from insulin for years — but it requires lifelong immunosuppression and is capped by a scarce cadaveric donor supply, so eligibility is narrow.

Available nowRegulator-approvedisletdonorcell-therapyimmunotherapyallogeneictransplant

The scorecard

Insulin independence65

Across the two pivotal trials, 21 of 30 recipients were insulin-independent for a year or more, and 25 of 30 achieved insulin independence at some point — real, but not universal.

Durability55

Function can last years (10 of 30 recipients stayed off insulin for over five years), but many grafts decline over time and some recipients resume insulin.

Immunosuppression-free15

Requires lifelong systemic immunosuppression (e.g. tacrolimus, sirolimus); roughly 87% of recipients had an infection-related adverse event — the central limitation.

Low invasiveness60

Delivered by infusion into the liver's portal vein, not open surgery, but the procedure carries bleeding risk (liver laceration/hematoma in about 13% of infusions).

Eligibility breadth20

Confined to adults with brittle T1D and severe hypoglycemia unresponsive to other care; deceased-donor scarcity caps treatable numbers at the low hundreds per year.

Maturity75

FDA-approved (2023) on BLA 125734 — the most regulator-validated cell therapy in this category — but not scalable as currently sourced.

The full picture

Donor islet transplantation puts working insulin-producing cells back into the body. Islets are isolated from the pancreas of one or more deceased organ donors, purified, and infused through a thin catheter into the portal vein of the liver, where they lodge, grow a blood supply, and begin releasing insulin in response to glucose.1 Marketed as Lantidra (donislecel), it is given as a single infusion, with up to three infusions used in the trials to reach a target islet dose.2

In June 2023 the FDA approved Lantidra — the first cell therapy of any kind approved for type 1 diabetes, and the first allogeneic (deceased-donor) pancreatic islet product.3 Approval rested on two single-arm studies (UIH-001 and UIH-002) in 30 adults with "brittle" T1D and severe hypoglycemia: 21 of 30 went without injected insulin for a year or more, including 10 who stayed insulin-free for over five years; across the program, 25 of 30 achieved insulin independence at some point.24 An earlier multicenter phase 3 trial of the same approach (48 patients) reported that 87.5% reached an HbA1c under 7.0% and were free of severe hypoglycemia at one year, with hypoglycemia awareness restored.5

The hard requirement is immunosuppression. To stop the immune system from rejecting the donor cells — and from re-attacking them as it did the original islets — recipients take lifelong immune-suppressing drugs (such as basiliximab induction, then tacrolimus and sirolimus).6 That carries real cost: roughly 87% of recipients had an infection-related adverse event, and the label flags serious risks from both the infusion (liver laceration, bleeding) and chronic immunosuppression (severe infections, malignancy, kidney decline).42 About 90% of participants had at least one serious adverse reaction.7

Durability and eligibility. Graft function often wanes over years, and some recipients return to insulin, though many keep partial function (detectable C-peptide) that still blunts dangerous lows.1 Because the trade-off — trading insulin for immunosuppression — only makes sense in the most dangerous cases, Lantidra is reserved for adults whose severe hypoglycemia persists despite optimized insulin, pumps, and CGM.31 The deeper ceiling is supply: islets come from deceased donors, so the number of people who can be treated is structurally limited to the low hundreds a year.1

What's coming. This therapy is best read as proof-of-concept for replacing the cells — the unsolved problems are an unlimited cell source and protection without lifelong drugs. The leading answer to supply is islets grown from stem cells: in 2025, Vertex's zimislecel (VX-880) reported that 10 of 12 recipients were insulin-independent at one year in an early-phase trial (NCT04786262), removing the donor-scarcity ceiling but still requiring immunosuppression.8 The remaining frontier — encapsulation and gene-edited "hypoimmune" cells that evade the immune system without drugs — is what would turn this narrow, last-resort procedure into a broadly usable cure.8

References

  1. Erbasan E, et al. Lantidra (donislecel) in type 1 diabetes: an in-depth analysis of pharmacology, clinical effectiveness, safety, and the therapeutic role of the first FDA-approved allogeneic islet cell therapy. Diabetic Medicine (2025/2026). PubMed (via PubMed). https://pubmed.ncbi.nlm.nih.gov/41219164/ ↩ ↩2 ↩3 ↩4

  2. Giri O, Goldman JD. Donislecel: first cellular therapy to treat patients with brittle type 1 diabetes. Clinical Diabetes (ADA) (2024). https://pmc.ncbi.nlm.nih.gov/articles/PMC11060608/ ↩ ↩2 ↩3

  3. U.S. Food and Drug Administration. FDA Approves First Cellular Therapy to Treat Patients with Type 1 Diabetes. FDA News Release (June 28, 2023). https://www.fda.gov/news-events/press-announcements/fda-approves-first-cellular-therapy-treat-patients-type-1-diabetes ↩ ↩2

  4. Parums DV. Editorial: First Regulatory Approval for Allogeneic Pancreatic Islet Beta Cell Infusion for Adult Patients with Type 1 Diabetes Mellitus. Medical Science Monitor (2023). https://pmc.ncbi.nlm.nih.gov/articles/PMC10403990/ ↩ ↩2

  5. Hering BJ, et al. Phase 3 Trial of Transplantation of Human Islets in Type 1 Diabetes Complicated by Severe Hypoglycemia. Diabetes Care (2016). PubMed (via PubMed). https://pubmed.ncbi.nlm.nih.gov/27208344/ ↩

  6. CellTrans Inc. / University of Illinois at Chicago. Islet Transplantation in Type 1 Diabetic Patients Using the UIC Protocol (Phase 3). ClinicalTrials.gov NCT00679042. https://clinicaltrials.gov/study/NCT00679042 ↩

  7. U.S. Food and Drug Administration. LANTIDRA (donislecel) Prescribing Information / Package Insert. FDA (2023). https://www.fda.gov/media/169920/download ↩

  8. Reichman TW, et al. Stem Cell–Derived, Fully Differentiated Islets for Type 1 Diabetes (zimislecel; VX-880 FORWARD, NCT04786262). New England Journal of Medicine (2025). PubMed (via PubMed). https://pubmed.ncbi.nlm.nih.gov/40544428/ ↩ ↩2