Sana Biotechnology’s 1-Year Results in UP421 Practical Cure Trial

January 16, 2026

Sana Biotechnology, a biotechnology company focused on creating engineered cells to solve the underlying cause of diseases, highlighted one-year results from Practical Cure trial, UP421, at the 44th annual J.P. Morgan Healthcare Conference. The clinical trial tests donor-derived islets gene edited as protection from the immune system, without traditional broad immunosuppression. The results show the donor cells evaded the immune system up to the twelve-month mark. However, c-peptide levels dropped by over half compared to six-month results.
 

About the Trial

UP421 is a phase I clinical trial testing the safety of genetically modified cadaver-sourced donor islets implanted into the forearm muscle of patients with long-standing type 1 diabetes. The trial made headlines last year as the first human trial to protect transplanted insulin-producing cells in an individual with established T1D, and without immunosuppression.

The study has one patient, a forty-three-year-old man diagnosed with T1D at the age of four with undetectable c-peptide at enrollment. The trial’s primary endpoint is safety; note that insufficient islets were transplanted to achieve insulin independence.

UP421 is being conducted at the University of Uppsala Hospital in Sweden and is led by Principal Investigator Per-Ola Carlsson. 
 

Results

Sana released several interim study results in 2025; the latest release is the first update since the six-month mark presented at the American Diabetes Association’s 85th Scientific Sessions.

Results indicate the patient suffered no drug-related adverse effects from the therapy. Transplanted islets continued to evade detection by the immune system and responded to changing glucose levels, as seen on PET and MRI imaging. However, c-peptide, a protein released when insulin is produced, dropped significantly between the six-month and twelve-month follow-up appointments.

Sana did not provide specific details on why the patient experienced a drop in c-peptide but listed several theories. Steve Harr, President, CEO & Director of the company, described this as unsurprising news during the conference, “Now it does look like the C-peptide levels are coming down a little bit over time . . . we don’t expect these cells to live forever.” The age of the cell donor (sixty-two years old) and significant cell stress (low dosage of cells trying to fulfill the body’s needs) were named as contributing factors.

An inquiry to Sana for more information regarding the drop has not yet been answered. JDCA will keep the T1D community updated with any response when it is received.
 

Next Up

Sana Biotechnology plans to initiate a new phase I clinical trial this year, testing the next-generation product, SC451. SC451 will replace donor-sourced cells with stem cell-derived islets. The same gene-editing targets will carry over into the new trial.

To ensure data gathered during the trial truly proves efficacy, JDCA strongly encourages three best practices:

1. Enroll a large group of individuals: Success in n=1 is a good start, but not enough to show the therapy is viable.
2. Transplant enough islets for insulin independence: The therapy must prove it can alleviate the burden of T1D.
3. Publish frequent interim results: Trial transparency and keeping the public up-to-date on how it fares are key. Furthermore, longer-term data (eighteen to twenty-four months) is essential in determining if the c-peptide drop seen in UP421 was due to stressed islets or if there is a larger issue with the therapy.

JDCA will keep you up-to-date with the latest T1D news as it unfolds in 2026.