A gentler anti-rejection drug for islet transplants: early but striking
A University of Chicago pilot reported all 10 evaluable islet-transplant patients came off insulin using tegoprubart, a gentler anti-rejection drug (ATTD 2026).
A small US pilot has tested a gentler anti-rejection drug for islet transplants, which are transplants of the insulin-making cells, and the early results are striking: all 10 people who were far enough along came off insulin. It is genuinely early, just a pilot, but it takes aim at the exact thing that has always held islet transplants back. This does not change anything a UK clinic can offer today, and islet transplants stay limited for reasons that go beyond this one drug.
- Islet transplants replace the insulin-making cells (the islets) using cells from a donor, and they already exist on the NHS for a small number of people.
- The long-standing catch is the anti-rejection drugs: they stop the body rejecting the transplant, but are harsh enough that transplants are reserved for the most severe cases.
- In this University of Chicago pilot, all 10 evaluable people became insulin-independent (off insulin) using a gentler anti-rejection drug called tegoprubart.
- Their most recent HbA1c (a blood test showing average glucose over about three months) was below 6.0%, which is in the non-diabetes range.
- It is a pilot of 10 people, very early, and does not change what is available in a UK clinic today.
A milder drug aimed at the real blocker
The results were shown at a diabetes technology conference (ATTD) in March 2026, from a pilot run at the University of Chicago. The idea is simple to describe: keep the islet transplant, but swap the usual harsh anti-rejection regimen for a gentler drug, tegoprubart. Among the patients who were more than four weeks past their transplant, all 10 who could be assessed were insulin-independent, with an HbA1c below 6.0%. What makes this worth noticing is where it aims. For years it has been the anti-rejection drugs, not the transplanted cells, that limit who can be offered an islet transplant, because those drugs carry their own serious risks.
Early and real, and years from a clinic
Two things are true at once: this is an encouraging result aimed squarely at the main problem, and it is very early. Ten people is a pilot, and it will take larger, longer trials to know whether the benefit lasts and whether the gentler drug is safe over years rather than months. Even if all of that goes well, islet transplants depend on donor cells, so supply would still limit how many people could benefit. In the UK, islet transplants are available on the NHS but are rationed to the most severe cases. A gentler anti-rejection drug could, in time, widen that, but the honest timeline is bigger trials and then a funding decision, which is years rather than months away.