- Tegoprubart is an experimental anti-rejection antibody (not approved, not available) that helped 12 islet-transplant patients achieve insulin independence in a small academic trial.
- If approved, it would almost certainly be a Part B drug — it's given by infusion in a clinical setting — while the transplant procedure itself is also a Part B medical benefit.
- Medicare's coverage of islet transplantation itself is limited today, so the real coverage question isn't just the drug — it's whether the procedure it supports becomes broadly covered.
The headlines are hard to miss: 12 people with type 1 diabetes, 12 off insulin. An experimental anti-rejection drug called tegoprubart, from Eledon Pharmaceuticals (Nasdaq: ELDN), replaced the harshest standard transplant drug in an islet-cell-transplant trial at the University of Chicago — and every patient achieved insulin independence with blood sugar in the non-diabetic range.
It's early, it's small, and the drug is not approved. But the coverage question it raises is worth understanding now: if a treatment like this were approved, how would Medicare pay for it?
The short answer: mostly Part B, not Part D
A treatment like this has two parts, and Medicare would likely handle each differently:
1. The transplant procedure itself — Part B (medical benefit). Islet cell transplantation is a medical procedure performed in a clinical facility, not a prescription you fill at a pharmacy. Procedures live under Part B (or Part A if inpatient). Here's the catch: Medicare's coverage of islet transplantation is limited today. Historically, Medicare has covered islet transplants primarily in the context of approved clinical trials (under "coverage with evidence development" policies), not as a routine benefit. The FDA approved the first donor-islet therapy, Lantidra, in June 2023 — but a covered procedure category and an approved drug are two different hurdles. Broader Medicare coverage of islet transplantation would need to catch up before most seniors could access it.
2. Tegoprubart itself — almost certainly Part B. Tegoprubart is a monoclonal antibody given by infusion in a clinical setting. Physician-administered infused drugs are Part B drugs, full stop — the same category as the IV therapy Tzield (teplizumab) for delaying type 1 diabetes onset. It would not be a Part D drug because patients don't pick it up at a pharmacy or take it at home.
3. The companion immunosuppressants — it depends. Standard anti-rejection drugs taken at home (like tacrolimus capsules or mycophenolate) are typically Part D drugs — except that Medicare Part B covers immunosuppressive drugs when they're tied to a Medicare-covered transplant, extending for as long as medically necessary after certain transplants. So the Part B vs. Part D split for the other drugs in the regimen would hinge on whether the transplant itself was Medicare-covered in the first place. Everything chains back to that first coverage decision.
What this means for costs
Under Original Medicare Part B, after the annual deductible, Medicare pays roughly 80% of the approved amount and you owe 20% coinsurance — with no annual out-of-pocket cap under Part B itself.
For the drug infusions, that math is manageable with the right supplemental coverage. But a transplant procedure plus ongoing specialty care is exactly the kind of high-cost episode where Medigap (which typically covers the 20% Part B coinsurance) or a Medicare Advantage plan's annual out-of-pocket maximum becomes the most important line in your coverage. If islet transplantation ever becomes a covered benefit, the seniors who can actually afford to use it will largely be the ones with strong supplemental coverage.
The bigger coverage question nobody's asking yet
Here's what makes this case interesting beyond one drug: tegoprubart doesn't replace a transplant — it makes the transplant's drug regimen safer. Its value is entirely chained to a procedure Medicare barely covers today. That means the advocacy and policy work that matters isn't just "get the drug approved" — it's "get the procedure covered." Drug approval and procedure coverage are separate gates, run by separate parts of the system (FDA vs. CMS), on separate timelines.
For seniors following this research, the practical takeaways:
- Today, nothing changes. Tegoprubart is investigational; islet transplant coverage under Medicare remains limited. Don't change your coverage based on headlines.
- During Annual Enrollment (Oct 15 – Dec 7), shop based on the drugs and care you actually use now — but if transplant-related therapies matter to your future, weigh the strength of a plan's Part B cost-sharing protections (Medigap or MA out-of-pocket caps), not just its Part D formulary.
- Free help exists: your State Health Insurance Assistance Program (SHIP) can walk through how Part B covers infused therapies and transplant-related care.
Science is opening doors. Coverage decides who gets to walk through them — and that second fight is worth watching just as closely as the first.
This article is educational and is not medical or insurance advice. Coverage rules change; confirm specifics with Medicare (1-800-MEDICARE) or your SHIP counselor before making decisions.