For decades, islet cell transplantation has offered something extraordinary for people living with type 1 diabetes (T1D): the possibility of restoring natural insulin production. But despite promising outcomes, the procedure has remained limited to a small group of patients.

The reason? The anti-rejection drugs.

Traditional immunosuppressive medications — like tacrolimus — help prevent the immune system from attacking transplanted cells. But they come with serious trade-offs: kidney toxicity, infection risk, and in some cases, direct harm to the insulin-producing islet cells themselves. For many people, the risks have outweighed the benefits.

Now, that balance may be shifting.

What’s New?

A novel investigational drug called tegoprubart (also known as AT-1501) is being studied in islet transplant recipients with T1D. Developed by Eledon Pharmaceuticals and tested in clinical trials at the University of Chicago Medicine, tegoprubart works differently from traditional immunosuppressants.

Instead of broadly suppressing the immune system, it targets a specific immune pathway — the CD40 ligand — which plays a key role in transplant rejection. By blocking this pathway, the drug appears to prevent rejection without the widespread toxicity seen in older medications.

The early results are turning heads.

What the Trial Results Show

In preliminary Phase I/II trial results:

All six transplant recipients treated with tegoprubart achieved sustained insulin independence.
Participants maintained stable blood glucose control without daily insulin injections.
Some individuals maintained normal A1C levels — including one as low as 4.7% — for over 15 months.
The safety profile appears significantly improved compared to traditional anti-rejection drugs.

These are early-stage results, and the sample size is small. But sustained insulin independence with reduced toxicity is exactly what researchers have been trying to achieve for decades.

Why This Matters for the T1D Community

If larger trials confirm these findings, the implications are significant:

1. Broader Access to Transplants
Safer immunosuppression could make islet transplantation available to more people — not just those with the most severe hypoglycemia or unstable control.

2. Better Long-Term Outcomes
Protecting transplanted islets from both immune attack and drug toxicity could extend graft survival.

3. Improved Quality of Life
Fewer side effects means fewer trade-offs — and potentially a life without daily insulin for some recipients.

This is not a cure yet. Islet transplantation still requires donor cells, specialized centers, and ongoing immune management. But what’s changing is the risk equation.

For the first time in years, the field may have found an immunosuppressive strategy that protects transplanted cells without harming the person receiving them.

A Realistic Perspective

It’s important to stay grounded. This is early clinical data from a small group of participants. Larger, longer-term trials will determine whether these results hold up.

But progress in T1D treatment doesn’t usually come in dramatic leaps. It comes in careful, incremental advances — and this may be one of those pivotal steps.

For those of us watching closely, tegoprubart represents something meaningful: movement.

Movement toward safer transplants.
Movement toward functional cures.
Movement toward a future where insulin independence may become more achievable — and less risky — than ever before.

We’ll continue following this closely and sharing updates as more data becomes available.

https://ir.eledon.com/news-releases/news-release-details/eledon-reports-preliminary-data-first-six-patients-type-1