Patients with diabetes given a stem cell transplantation were able to go without insulin for over three years in some cases, according to a new study in JAMA.

Researchers from American and Brazil treated 23 patients with type 1 diabetes and 20 used less insulin or none at all during the follow-up period, 12 continuously and 8 transiently. The idea is to stop the patients’ own immune systems attacking insulin-producing cells.

“We were trying to preserve islet beta cell mass, that is, the cells that produce insulin, by stopping the immune system attack on these cells,” says study author Richard Burt, of Northwestern University (Forbes).

“Why new onset? Because we wanted to make sure there were still some islets there. We don’t believe stem cells form islet cells, but if the islet cells are still there, there might be regeneration if we stop the attack soon enough.”

Burt told New Scientist this is the first treatment that has freed patients from insulin, although he adds “I never say it’s a cure”. He told Bloomberg he has been working in this area for 20 years and “it’s now in the hands of the FDA”.

Time points out that some of these results were initially announced previously:

The group first reported its initial achievement in 2007, with 15 type 1 diabetes patients who received their own stem cells and no longer needed insulin to control their blood sugar levels. In the new study, a follow-up of their previous work, [co-author] Voltarelli and his colleagues detailed the same success with an additional eight patients, and also confirmed that in the majority of them, the stem cell transplant led to an appreciable repopulation of functioning insulin-producing beta cells in the pancreas.

Iain Frame, Director of Research the charity Diabetes UK, says (Daily Telegraph), “Although this remains an interesting area of research, the importance of a limited extension to this study should not be overstated – this is not a cure for Type 1 diabetes. As we said in 2007, we would like to see this experiment carried out with a control group for comparison of results and a longer-term follow up in a greater number of people.”