Until December 2009, 12 patients remained continuously insulin-free for periods ranging from 14 to 52 months and 8 patients became transiently insulin-free for periods ranging from 6 to 47 months. Of these last 8 patients, 2 became insulin-free again after the use of sitagliptin, a DPP-4 inhibitor approved only to treat type 2 diabetic patients and this is also the first study to document the use and complete insulin-independendce in humans with type 1 diabetes with this medication. In parallel with insulin suspension, indirect measures of endogenous insulin secretion revealed that it significantly increased in the whole group of patients, regardless the need of daily exogenous insulin use. Gene therapy Technology for gene therapy is advancing rapidly such that there are multiple pathways possible to support endocrine function, with potential to practically cure diabetes. Gene therapy can be used to manufacture insulin directly: an oral medication, consisting of viral vectors containing the insulin sequence, is digested and delivers its genes to the upper intestines. Those intestinal cells will then behave like any viral infected cell, and will reproduce the insulin protein. The virus can be controlled to infect only the cells which respond to the presence of glucose, such that insulin is produced only in the presence of high glucose levels. Due to the limited numbers of vectors delivered, very few intestinal cells would actually be impacted and would die off naturally in a few days. Therefore, by varying the amount of oral medication used, the amount of insulin created by gene therapy can be increased or decreased as needed. As the insulin-producing intestinal cells die off, they are boosted by additional oral medications. Gene therapy might eventually be used to cure the cause of beta cell destruction, thereby curing the new diabetes patient before the beta cell destruction is complete and irreversible. Gene therapy can be used to turn duodenum cells and duodenum adult stem cells into beta cells which produce insulin and amylin naturally. By delivering beta cell DNA to the intestine cells in the duodenum, a few intestine cells will turn into beta cells, and subsequently adult stem cells will develop into beta cells. This makes the supply of beta cells in the duodenum self-replenishing, and the beta cells will produce insulin in proportional response to carbohydrates consumed. Monoclonal antibodies In November 2022 the FDA approved Teplizumab a monoclonal antibody drug which aims to delay type 1