The Pre-POINT study , a double-blind , placebo-controlled , dose-escalation , phase 1/2 clinical pilot study performed between 2009 and 2013 in Germany , Austria , the United States , and the United Kingdom and enrolling 25 islet autoantibody-negative children aged 2 to 7 years with a family history of type 1 diabetes and susceptible human leukocyte antigen class II genotypes .