OZTx-410 allogeneic iPSC islet cell sheet (Orizuru)
Orizuru Therapeutics, Inc.
Very early — but a genuinely different delivery route.
OZTx-410 is an allogeneic islet product grown from induced pluripotent stem (iPS) cells and formed into a sheet, then implanted under the skin of the abdomen rather than infused into the liver. A physician-initiated Phase 1/1b trial (OASiS-1) at Kyoto University Hospital, run with Orizuru Therapeutics, planned three adults with type 1 diabetes and has closed to recruitment. Immunosuppressants are given alongside the transplant, the primary endpoint is safety, and no efficacy results have been published.
The scorecard
No efficacy results have been published. The trial's primary outcome is safety (adverse events within one year); anything about insulin use or C-peptide is a secondary measure, so insulin independence in people with T1D is entirely unproven here.[1]
Follow-up runs to 2030, which is long enough to say something useful about durability eventually — but no graft-function or C-peptide data have been reported at all so far.[1]
Anti-rejection drugs are given alongside the transplant (the protocol specifies mycophenolate mofetil). This is not an immunosuppression-free approach, and the sheet format is not designed to shield the cells from the immune system on its own.[1]
The sheet is implanted under the skin of the abdomen under general anaesthesia — more involved than a vein infusion, but the graft sits in an accessible place and is in principle removable, unlike islets scattered through the liver.[1]
Three planned participants, aged 20 to under 65, already eligible for pancreatic islet transplantation, at a single hospital in Japan. Recruitment has closed, so there is no way in.[1]
A physician-initiated Phase 1/1b study with three planned subjects — the earliest stage of human testing, with no published readout of any kind.[1]
The full picture
What it is
OZTx-410 is an allogeneic islet product made from induced pluripotent stem (iPS) cells — reprogrammed cells that can be grown indefinitely and then coaxed into becoming insulin-producing islet cells. Like every stem-cell islet programme, the point is to escape the supply ceiling of deceased-donor pancreases.
What makes it different is the format and the site. Rather than being infused as loose clusters into the hepatic portal vein — the standard route for donor islets and for most stem-cell islet products — OZTx-410 is grown into a cell sheet and implanted subcutaneously, under the skin of the abdomen, under general anaesthesia.1 That trade is deliberate: a subcutaneous sheet is a surgical implant rather than an infusion, but it sits somewhere a surgeon can find again. Intrahepatic islets, once infused, cannot practically be removed. A sheet under the skin is, in principle, retrievable — which matters for safety with any stem-cell-derived product, and matters for anyone thinking about what happens if the graft misbehaves.
It is also, as far as we can find, the only Japanese cell-replacement programme in T1D that has reached human testing.
Clinical status
The trial is OASiS-1 (jRCT2053240146), a physician-initiated Phase 1/1b study at Kyoto University Hospital (lead investigator Daisuke Yabe), run with Orizuru Therapeutics, Inc., which supplies the cells.1 Key facts from the registry:
- 3 planned subjects, aged 20 to under 65, who are already eligible for pancreatic islet transplantation.1
- Primary endpoint: safety — adverse events within one year of transplant. Efficacy measures are secondary.1
- Status: not recruiting. Enrolment has closed.1
- Started January 2025; expected completion August 2030.1
Press reporting from April 2025 said a first participant had been transplanted and that no major safety problems had appeared at one month.2 Treat that as press reporting and nothing more: it is not confirmed in the registry, it has not been published, and "no major safety issues at one month" in a single person is not a result. The registry itself lists three subjects as planned, not as dosed.
Immunosuppression is still required
This is the honest headline, and it is easy to lose in the excitement about iPS cells. OZTx-410 is given with anti-rejection drugs — the protocol specifies mycophenolate mofetil.1 The cell sheet is a delivery format, not an immune shield. So this approach inherits the same central problem as donor-islet transplantation and as Vertex's zimislecel: it can only be offered to people for whom lifelong immunosuppression is a reasonable trade, which today means a small group with severe, dangerous hypoglycemia — not the general T1D population.
Retrievability is a real advantage over portal-vein infusion. Freedom from immunosuppression is not something this programme claims.
How to read it
Three planned participants, safety as the primary endpoint, no published data, and follow-up that runs to 2030. On the evidence available, this is one of the earliest programmes on this site, and its scores reflect that. What earns it a place is not its results — it has none — but the fact that it is testing a delivery route almost nobody else is testing in humans, in a place where nobody else is running these trials. If a subcutaneous sheet turns out to engraft and survive, that finding would matter well beyond Orizuru.
Watch for: a published safety readout, any C-peptide or insulin-use data, and whether Orizuru moves toward a company-sponsored trial with real enrolment.
References
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Kyoto University Hospital / Orizuru Therapeutics, Inc. Phase 1/1b trial to evaluate the safety of OZTx-410, allogeneic iPS cell derived islet cell sheet in individuals with type 1 diabetes eligible for pancreatic islet transplantation (OASiS-1). jRCT jRCT2053240146. https://jrct.mhlw.go.jp/latest-detail/jRCT2053240146 ↩ ↩2 ↩3 ↩4 ↩5 ↩6 ↩7
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Window to Japan. Kyoto University Hospital and Orizuru Therapeutics have started phase 1 clinical trials with transplanted iPS-cell-derived islet cells (April 22, 2025) — secondary press reporting, not a registry statement or peer-reviewed publication. https://window-to-japan.eu/2025/04/22/kyoto-university-hospital-and-orizuru-therapeutics-have-started-phase-1-clinical-trials-with-transplanted-ips-cell-derived-islet-cells/ ↩
Coming soon
ETA · Physician-initiated Phase 1/1b (OASiS-1) is closed to recruitment, with safety follow-up running to August 2030. No efficacy data have been published, and the trial is far too small to support approval on its own — this is years away from being anything you could receive
- →First safety readout from OASiS-1 (primary endpoint is adverse events within one year of transplant) · Not scheduled publicly
- →End of OASiS-1 follow-up · Aug 2030
Sources
- [1]Phase 1/1b trial to evaluate the safety of OZTx-410, allogeneic iPS cell derived islet cell sheet in individuals with type 1 diabetes eligible for pancreatic islet transplantation (OASiS-1; jRCT2053240146) · registry · 2025-01-01 — Physician-initiated; institution Kyoto University Hospital (lead investigator Daisuke Yabe); company partner Orizuru Therapeutics, Inc.; 3 planned subjects aged 20 to under 65; implanted subcutaneously under general anaesthesia; immunosuppression (mycophenolate mofetil) specified; status not recruiting; start 2025-01-01, expected completion 2030-08-31.
- [2]Kyoto University Hospital and Orizuru Therapeutics have started phase 1 clinical trials with transplanted iPS-cell-derived islet cells · news · 2025-04-22 — Secondary press reporting, not a registry statement or a published paper. Cited only for the claim that a first participant had been transplanted by April 2025.