Interim results from a multicenter clinical trial demonstrate insulin secretion from engrafted cells in patients with type 1 diabetes. The safety, tolerability, and efficacy of the implants, which consisted of pancreatic endoderm cells derived from human pluripotent stem cells (PSCs), were tested in 26 patients. While the insulin secreted by the implants did not have clinical effects in the patients, the data are the first reported evidence of meal-regulated insulin secretion by differentiated stem cells in human patients. The results appear December 2 in the journals Cell Stem Cell and Cell Reports Medicine.