In type 1 diabetes, the immune system mistakenly attacks and destroys beta cells in the pancreas – the cells that make insulin.
Beta cell therapies aim to replace or restore these lost beta cells, allowing the body to produce its own insulin again.
While diabetes technologies have made life safer and easier, they can’t match the body’s natural, finely tuned control of blood sugar. And they require people with type 1 to shoulder a relentless, lifelong load of decisions, calculations and worry.
Restoring insulin production would mean freedom from that constant mental load, stable blood sugars and protection from diabetes complications. For many people living with type 1 diabetes, beta cell therapy represents the ultimate hope: a cure.
We’re funding research to bring these treatments closer, including a £30 million investment through the Type 1 Diabetes Grand Challenge. This is supporting 10 groundbreaking projects and building a network to make the UK a global leader for beta cell therapy clinical trials.
Islet cell transplantation: what we have now
A form of beta cell therapy already exists: islet transplantation. Diabetes UK researchers helped pioneer the treatment and led the way for it to be made available on the NHS.
Islets are clusters of cells in the pancreas. Doctors take islets from a donor pancreas and transplant them into the liver of a person with type 1 diabetes, where the transplanted beta cells begin making insulin.
This can reduce or temporarily eliminate the need for insulin therapy, improve blood sugar levels and protect people from life‑threatening hypos.
However, islet transplants are currently far from a cure and are not suitable for most people type 1 diabetes. Fewer than 350 transplants have happened in the UK since they became available in 2008.
This is because donor islets are scarce and recipients must take lifelong immunosuppressive drugs to stop the body rejecting the 'foreign' donor cells. These can have serious side effects, like kidney damage and an increased risk of dangerous infections.
And even with immunosuppression, transplanted cells often struggle to survive long‑term because they don’t get enough oxygen and nutrients. This means that, over time, most recipients need insulin therapy again.
What’s coming: trials to watch
Better immune protection
At the moment, the powerful anti-rejection drugs people take after islet transplants suppress their whole immune system. But researchers at the University of Chicago have been testing a more precise and potentially safer alternative.
A new drug called tegoprubart only targets a specific part of the immune system that's involved in transplant rejection. This could allow transplanted beta cells to survive without many of the risks linked to current immunosuppressives.
In an early clinical trial, 12 adults with type 1 diabetes received islet transplants alongside tegoprubart. The results so far are looking promising.
Participants all began producing their own insulin after transplant, many were able to stop insulin therapy within weeks, and some have remained insulin‑free for over a year. Blood sugar levels improved significantly, with no signs of transplant rejection or any of side effects linked to standard immunosuppression so far.
These early findings suggest that targeted anti‑rejection drugs like tegoprubart could make islet transplants safer and more widely available to people with type 1 diabetes. Larger and longer studies will now be needed to confirm how well this approach works and how long transplanted cells can survive.
But, a key limitation is the reliance on a limited supply of donor cells, alongside the need for lifelong drug treatment.
Immune‑evasive beta cells
Scientists from Sana Biotechnology are taking a different approach, aiming to avoid the need for immunosuppression altogether. They have genetically modified donor beta cells to make them invisible to the immune system.
Sana reported results from the first person to receive these edited cells. Fourteen months after transplant, the cells were alive, were producing insulin and no immunosuppressive drugs were needed.
By addressing one of the biggest barriers to beta cell therapies - lifelong immune suppression - this approach could open up these treatment to many more people. But it's still very early days.
This route also still depends on donor cells, and there simply aren't enough available.
Creating new beta cells
To overcome the shortage of donor cells, scientists have turned to stem cells. They can be grown in the lab and coaxed into becoming beta cells. This opens the door to an unlimited supply of beta cells, potentially making transplants available to many more people with type 1 diabetes.
One of the most progressed cell therapies comes from a biotech company called Vertex and is providing promising evidence that lab-made beta cell therapies can work.
Vertex’s therapy, called zimislecel, has been tested in 12 people with type 1 diabetes who have severe hypos. After one year, the latest results show the transplanted cells were still producing insulin and 10 out of 12 participants had stopped insulin therapy completely, with blood sugar levels close to normal.
The main drawback here is that powerful immunosuppressive drugs are used alongside zimislecel to prevent rejection, bringing the risk of major side effects.
Zimislecel has now moved into a large phase 3 clinical trial, with sites in the UK. If successful, Vertex hopes to apply for regulatory approval, first in the US, in 2026. Initially, this treatment would likely be offered to adults at high risk from life-threatening hypos due to the risks of immunosuppression.
Personalised stem cell therapy
A team of researchers in China has taken yet another route. They’ve grown new beta cells from a person’s own stem cells and transplanted them back into that same person. Because the cells come from their own body, they’re less likely to be rejected by the immune system.
In 2024, the team reported results from the first person to receive this therapy. After 10 weeks, they were producing enough insulin to stop insulin injections. A year later, they were still making insulin and their blood sugar levels were in range for 98% of the time.
While this has only been tested in one person so far, it offers a glimpse of what personalised beta cell therapy could look like.
Towards a cure
This is a pivotal moment for type 1 diabetes research. Clinical trials are showing that it's possible to restore the body’s own insulin production. While these therapies are still at an early stage, they represent one of the clearest paths toward a cure.
But there will be challenges ahead. Not every approach has worked so far. For example, some early trials using devices to physically shield transplanted beta cells from the immune system have had limited success. These lessons are helping researchers design smarter materials and better transplant approaches to support long‑term cell survival.
Even with rapid progress, beta cell therapies will need several more years of testing to find out if they are safe, effective for a wide group of people, and affordable for widespread use.
That’s why our Type 1 Diabetes Grand Challenge scientists are working to speed up the journey from discoveries in the lab, to clinical trials, to real‑world treatments. They’re building better performing beta cells, creating innovative ways to protect them after transplant, and exploring drugs to regrow beta cells within the pancreas.
With continued research, collaboration and investment, beta cell therapies could become a life‑changing reality for people living with type 1 diabetes.
Join our Type 1 Tipping Point campaign and help us call on UK governments to act now to make this happen.
