Juicebox Podcast Episode #1817: Transplanting Islet Cells with Piotr Witkowski, MD, PhD

Host: Scott Benner
Guest: Dr. Piotr Witkowski, University of Chicago
Date: April 6, 2026

Episode Overview

This episode features a deep-dive conversation with Dr. Piotr Witkowski, Director of Pancreatic Islet Cell Transplantation at the University of Chicago. Dr. Witkowski discusses the evolution and current state of islet transplantation for people with Type 1 diabetes, focusing especially on challenges in the U.S. regulatory environment, promising clinical trial results with a new immunosuppressive drug, and the path towards broader access. The episode unpacks the scientific, clinical, and personal dimensions of islet cell transplantation as both a reality and a hope for the future.

Key Discussion Points & Insights

1. Background and Evolution of Islet Cell Transplantation

• History & Regulation in the U.S.

  • Islet transplantation has not been widely adopted in the U.S. because islets are regulated as a "drug" by the FDA, not as an organ, creating immense inflexibility in clinical practice.
    • "It took us over 15, 18 years to accomplish those trials. And over this time we couldn't really modify anything, only because it's been regulated as a drug." – Dr. Witkowski [04:43]
  • By contrast, Canada, Europe, and Australia treat islets as organs, leading to faster advancements and standard of care implementation.
    • "In Canada, they've done over 700 islet transplants over the last 20 years. In Europe... over a thousand." – Dr. Witkowski [06:08]

• Clinical Challenges

  • Progress has been hampered by tight clinical protocols and lack of flexibility during long phases of FDA-required trials.
  • Funding and trial participant numbers were also bottlenecks.

2. Recent Advances and Game-Changers

• Emergence of New Immunosuppressants

  • Historically, immunosuppression after transplantation caused significant side effects, making islet transplantation a trade-off. Newer drugs (notably Tegoprubart from Eledon and a similar product from Sanofi) are showing far fewer side effects.
    • “With take Approbar (Tegoprubart)... we have only 12 patients and short observation, but all the patients do not have those side effects." – Dr. Witkowski [12:18]
  • Tegoprubart is currently delivered via IV every 21 days, but subcutaneous at-home dosing is on the near-term horizon.
    • "Moving on... the company is already working on subcutaneous infusion... the dose may be lower in the future.” – Dr. Witkowski [16:25]

• Impact for Patients & Scope

  • Early results: No hypoglycemia, good glucose control, patients living “free of insulin” (in small, highly selected groups).
    • “They feel cured because they don’t feel burdened of this therapy.” – Dr. Witkowski [12:18]
  • Not a cure for all—currently focused on the most desperate cases and will take years for broad availability.

3. Regulatory and Access Bottlenecks

• Regulatory change would allow islets to be treated as organs, enabling insurance reimbursement and greater trial flexibility:
  • "Once the islets are regulated as organ, our product would be approved and then it can be reimbursed... we can offer this to many more patients." – Dr. Witkowski [08:38]
  • Grassroots and foundation (Breakthrough T1D) advocacy have increased pressure on HHS and FDA to change the rules.
    • "There was no really traction until recently... now there is a hope that this regulatory adjustment may happen." – Dr. Witkowski [06:59]

Call to Action

• Patients and the community are encouraged to express support to HHS for regulatory change.
  • "HHS should hear from everybody that this is the right thing to do... their job is to analyze it and frame it in the proper way." – Dr. Witkowski [56:36]

4. The Ladder to a Real Cure

• Incremental Progress
  • Islet transplantation (even perfected) is an important step—NOT the endpoint. Eliminating immunosuppression is still crucial.
    • "It’s another step on the ladder... but the ultimate goal is to do it without immunosuppression." – Dr. Witkowski [24:14]
  • Encapsulation (putting islets in a pouch) and genetic masking remain theoretical and face significant biological hurdles.
    • "I do not believe that encapsulation is the solution because they need blood supply... genetics will be hard." – Dr. Witkowski [25:45 & 27:11]

5. Realistic Expectations for Patients

• Who Can Benefit?
  • Current protocols focus on severely affected adults (not children yet; pediatric testing is a distant goal).
  • "It’s not for children yet... eyelet transplantation is not for children because we're using toxic immunosuppression and then it's not justified yet." – Dr. Witkowski [46:54]
• Maintaining Health Remains Vital
  • "Patients should take care of themselves and keep themselves as healthy as possible that when one day the real cure is available, they will not have problems." – Dr. Witkowski [29:06]
• Timelines
  • This is not a universal, overnight fix. Approval of new agents and expansion to a wide patient pool will take years.
    • “It's a small group of people from a highly curated group of people... I’m not saying 5 years. It might be much longer." – Dr. Witkowski [29:48]

6. Trial Mechanics, Costs, and Expansion Potential

• Trial Status and Access
  • Currently, 12 patients enrolled in the main Tegoprubart trial, with open spots in a new trial for patients with kidney dysfunction.
    • "We still have open spots... the Eledon Dego Probart study." – Dr. Witkowski [65:04]
    • Website for information and enrollment: [pwakowski.org] (best used on a desktop/laptop). [66:01]
• Cost
  • Full cost per transplant currently around $800,000 due to small scale and multi-factorial requirements.
    • "If you do more, the cost per procedure is lower... but if a center wants to start, they need $8 million for 10 transplants." – Dr. Witkowski [39:25]
• Capacity
  • Currently around 40 transplants/year in the U.S.; theoretical scaling to 1,000 (still a tiny fraction of 2M+ potential patients).
    • "If we do a thousand transplants a year, that would be amazing." – Dr. Witkowski [58:19]

7. The Human Side

• Emotional Impact

  • Tremendous reward for team and patients when insulin is stopped, but life’s other challenges soon return.
    • "This is what's driving all of us, our entire team... the best reward is when we can tell patients, ‘You can stop the pump.’" – Dr. Witkowski [47:02]
    • "But the next day... 'Oh, I have a problem with my car.' So this happiness, which I thought would stay forever—no, these are regular people who have regular problems." – Dr. Witkowski [73:28]

• Teaching and Mentorship

  • Dr. Witkowski emphasizes teaching surgical fellows with the same attention to detail that shaped his own training.
    • "I'm telling my fellows... you can choose your way, but I'm telling this is better and you can do what you want with that.” – Dr. Witkowski [37:01]

Notable Quotes & Memorable Moments

"Regulations which have been applied in the United States—and only the United States—have not really helped the progress in the field."
– Dr. Witkowski [04:43]

"We can offer this procedure to many more patients and then we can do many more studies and enroll patients faster and learn faster and progress the field."
– Dr. Witkowski [08:38]

"Now with take Approbar... all patients do not have those side effects. They have islets transplants successful and reverse diabetes."
– Dr. Witkowski [12:18]

"I do not believe that encapsulation is the solution because they need blood supply."
– Dr. Witkowski [25:45]

"Patients should stay as healthy as possible. When the cure comes one day... I'm not saying five years. It might be much longer."
– Dr. Witkowski [29:06, 29:48]

Host Scott Benner:
"What do you consider a cure? ...What would you be comfortable, not saying 'functional cure'...?"
Dr. Witkowski:
"The ultimate cure is something which can reverse diabetes in a consistent way forever without any side effects."
[30:52]

"HHS should hear from everybody that this is the right thing to do—not only us physicians and experts, from patients, endocrinologists, from everyone."
– Dr. Witkowski [56:36]

"This time we are just lucky the approach we are testing is working better than anything else."
– Dr. Witkowski [67:18]

Timestamps for Key Segments

• Introduction & Dr. Witkowski's Background [02:03]
• The Regulatory Challenge in the U.S. [04:43]
• Global Progress vs U.S. Standstill [06:08]
• Breakthrough T1D's Advocacy Role [06:59]
• Potential of Insurance Reimbursement [08:38]
• Advancements with New Immunosuppressants (Tegoprubart) [12:18]
• Prospects for At-home/SC Administration [16:25]
• Limitations for Children, Expansion to New Groups [43:20, 46:54]
• Trial Participation & How to Enroll [65:04]
• Cost of Transplant/Scaling Challenges [39:25, 58:19]
• Emotional Impact for Patients & Team [47:02, 73:28]
• Advocacy: What Listeners Can Do [51:01, 56:36]
• Discussion of What a Real Cure Means [30:52]
• Long-Term Perspective on Progress [61:46, 62:13]
• Mentorship & Teaching Legacy [36:01]
• Hope for AI in Medical Discovery [37:37]

Additional Resources

• Website for Clinical Trial/Elegibility: [pwakowski.org] (desktop/laptop recommended) [66:01]
• Documentary Mentioned: The Human Trial [67:54]

Concluding Notes

Dr. Witkowski offers both realism and hope: islet transplantation is not a universal, immediate cure, but marks a crucial step forward for those most vulnerable and for diabetes research as a whole. Progress depends not only on science and medicine but also on regulatory reform, advocacy, and collective action.

To help accelerate access:

• Contact HHS and voice support for regulatory change—making islet cell transplantation more available to those in greatest need.
• Interested patients (especially with Type 1 diabetes & kidney dysfunction) can explore ongoing trials at [pwakowski.org].

This summary offers a roadmap for listeners and non-listeners alike to grasp where we are—and where we're headed—on the path to truly bold advances in diabetes care.