Stem cell therapy offers hope for type 1 diabetes patients

In what could be a potential breakthrough in the treatment of type 1 diabetes, a novel stem cell therapy named zimislecel has demonstrated promising results in an early-phase clinical trial. The therapy, which involves transplantation of fully differentiated islet cells derived from stem cells, enabled 83 per cent of trial participants to stop using insulin entirely within a year of receiving the full dose.

 

Type 1 diabetes is a chronic autoimmune condition where the body’s immune system attacks and destroys insulin-producing beta cells in the pancreas. This lifelong condition requires daily insulin therapy and carries the risk of severe hypoglycaemic episodes. Restoring lost islet function has long been a goal in diabetes research, and zimislecel might just be a step closer to realising it.

 

The study, recently published in the New England Journal of Medicine, evaluated the safety and effectiveness of zimislecel in a phase 1-2 trial involving 14 individuals with type 1 diabetes. All participants had undetectable levels of C-peptide—a marker of insulin production—at the start of the study.

 

The participants were divided into three groups. Two individuals received a half dose of zimislecel (0.4×10⁹ cells) with an option for a repeat dose. The remaining 12 participants received a full dose (0.8×10⁹ cells) in a single sitting. Importantly, the therapy was administered without glucocorticoids—steroids that are typically used to suppress immune response but can cause metabolic side effects.

 

The results were encouraging. All 14 individuals showed signs of islet cell engraftment and function post-treatment. Among those who received the full dose, 100 per cent were free from severe hypoglycaemic events, and all met the HbA1c targets. They also spent more than 70 per cent of their time in the optimal blood glucose range, a substantial improvement.

Most strikingly, 10 out of 12 full-dose recipients—approximately 83 per cent—achieved insulin independence at the one-year mark.

 

“This study represents a meaningful leap toward a functional cure for Type 1 diabetes,” said lead investigator Dr Thomas W. Reichman. “While we remain cautious due to the small sample size and limited follow-up, the early signals are very positive.”

 

However, the therapy is not without risks. The most common serious side effect was neutropenia—a dangerous drop in white blood cells—seen in three participants. Two deaths occurred during the study: one due to cryptococcal meningitis, a fungal infection, and the other in a participant with severe pre-existing neurocognitive decline. 

 

Experts in the field have responded with cautious optimism. “The field of regenerative medicine has been seeking scalable, stem cell-based solutions for diabetes for years,” said a Mumbai-based endocrinologist not involved in the study. “If zimislecel continues to show this kind of efficacy in larger trials, it could truly change the treatment landscape.”

 

The need for alternatives to insulin is pressing. A therapy that replaces lost beta-cell function and reduces or eliminates the need for insulin could vastly improve patients’ quality of life.

 

The trial involved a small number of patients and follow-up was limited to one year. The next steps will include larger, longer trials to confirm efficacy and monitor long-term safety.

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