Also in 2000, the FDA granted marketing approval for a long-acting insulin analog called insulin glargine (brand name Lantus), manufactured by Aventis Pharmaceuticals. In insulin glargine, two molecules of the amino acid arginine are added to one end of the B chain, and one molecule of glycine is substituted for asparagine at position A21. The previously available intermediate-acting insulin NPH is absorbed somewhat unevenly into the bloodstream and has a pronounced “peak” in its activity level. Insulin glargine, however, because of its altered structure, is released very slowly and evenly into the bloodstream. Since its effects last nearly 24 hours with little variability and no peak action level, insulin glargine could be an ideal basal, or long-acting, insulin. A number of studies have compared the use of insulin glargine with that of the widely used NPH. They showed that regimens using insulin glargine offered blood glucose control that was at least as good as and sometimes better than that seen with NPH, and produced fewer episodes of hypoglycemia and less weight gain.
Researchers and manufacturers continue to look for more effective basal insulin analogs. In 2005, a new basal insulin analog called insulin detemir, marketed by Novo Nordisk as Levemir, was approved by the FDA. In insulin detemir, the amino acid threonine is removed from position B30 and a fatty acid is chemically linked to the amino acid lysine at position B29. These changes cause insulin detemir to bind readily to albumin, a protein found in the body, and dissociate slowly, thus prolonging its effect. Insulin detemir lasts an average of 14 hours.