An innovative stem cell-based treatment for type-1 diabetes can meaningfully regulate blood glucose levels and reduce dependence on daily insulin injections, according to results from a clinical trial.

The therapy aims to replace the insulin-producing beta cells that people with type 1 diabetes lack. Dubbed VC-02, the small medical implant contains millions of lab-grown pancreatic islet cells, including beta cells, that originate from a line of pluripotent stem cells.

"This is a significant step toward a functional cure for type 1 diabetes," said David Thompson, principal investigator at the Vancouver trial site, clinical professor of endocrinology at the University of British Columbia (UBC)

"For the first time, a stem cell-based device can reduce the amount of insulin required for some trial participants with type 1 diabetes. With further refinement of this approach, it's only a matter of time until we have a therapy that can eliminate the need for daily insulin injections entirely," he added.

The findings, published in the journal Nature Biotechnology, are based on a multicenter clinical trial for an experimental cell therapy developed by US biotechnology company ViaCyte (acquired by Vertex Pharmaceuticals) that is being clinically tested in Canada.

The devices -- approximately the size of a Band-Aid and no thicker than a credit card -- are implanted just beneath a patient's skin where it is hoped they will provide a steady, long-term regulated supply of self-sustaining insulin.

"Each device is like a miniature insulin-producing factory," said co-author Timothy Kieffer, a professor within the departments of surgery and cellular and physiological sciences at UBC, and past chief scientific officer of ViaCyte.

"The pancreatic islet cells, grown from stem cells, are packaged into the device to essentially recreate the blood sugar-regulating functions of a healthy pancreas. This may have tremendous benefits over transplant of scarcely available donor-derived cells, given that we can create a virtually limitless supply."

The clinical trial was conducted at Vancouver General Hospital, with additional sites in Belgium and the US. Ten participants, each of whom had no detectable insulin production at the start of the study, underwent surgery to receive up to 10 device implants each.

Six months later, three participants showed significant markers of insulin production and maintained those levels throughout the remainder of the year-long study. These participants spent more time in an optimal blood glucose range and reduced their intake of externally administered insulin.

One participant, in particular, showed remarkable improvement, with time spent in the target blood glucose range increasing from 55 per cent to 85 per cent, and a 44 per cent reduction in their daily insulin administration.

In another ongoing trial, the team is investigating whether a version of the device containing cells that have been genetically engineered to evade the immune system, using CRISPR gene-editing technology, could eliminate the need for participants to take immunosuppressant drugs alongside the treatment.