Updated Oct. 13

Researchers have made a major breakthrough in finding a treatment for type 1 diabetes, Harvard University announced Thursday.

For the first time, scientists were able to create insulin-producing beta cells using human embryonic stem cells, at a volume required for cell transplantation and pharmaceutical use. Type 1 is the variety of the metabolic disease that can be inherited and which is likely due to an underlying autoimmune condition in which the body destroys the beta cells that produce insulin, a hormone that regulates glucose and helps the body process sugar. (Unlike type-2 diabetes, there is no way to prevent type-1.)

“We are now just one pre-clinical step away from the finish line,” said Doug Melton, who led the research and who has worked toward finding a cure for diabetes since his son was diagnosed as an infant 23 years ago.

That final step is finding a way to protect the 150 million beta cells needed to for transplant in the treatment of each patient from their immune systems, which automatically attack those cells. Melton is working with other researchers to develop a device for such protection. Tests of a device in mice have so far protected insulin-producing beta cells for several months.

Write to Nolan Feeney at nolan.feeney@time.com.