A great deal of research on potential drug treatments for diabetes is under way, including:

• Incretin mimetics (GLP-1 agonists). Researchers are working on a longer-acting version of exenatide (Byetta) that could be injected only weekly instead of twice daily. Other incretins being assessed in clinical trials include liraglutide, which is also being studied as a potential treatment for obese nondiabetics, and albiglutide.
  
  
• Weight-loss drugs. Studies have shown that rimonabant (Acomplia), in addition to helping patients lose weight, might help control glucose and improve cardiovascular health by reducing triglycerides and increased HDL "good" cholesterol. Rimonabant has been approved in the European Union, but concerns raised before the U.S. Food and Drug Administration (FDA) include possible psychiatric side effects such as depression and anxiety. For this reason, rimonabant is not currently available in the United States.
  
  Other drugs being studied to treat obesity and type 2 diabetes include cetilistat (a gastrointestinal lipase inhibitor), BAY 74-4113 (which also modifies the metabolism of lipids), appetite-controlling hormones such as leptin and ghrelin, and quercetin, a flavinoid (antioxidant plant pigment) found in food including apples and tea.
  
  

  

• Vaccines. Clinical trials involving people with recent-onset type 1 diabetes have shown promise for Diamyd, a potential vaccination against diabetes. Diamyd appears to preserve beta cells in the pancreas and enhance their production of insulin. The vaccine may also help treat type 2 diabetes.
  
  
• Insulin pills. Clinical trials are examining the effect of oral insulin tablets on people with type 2 diabetes.
  
  
• Glitazars. The FDA appeared poised to approve muraglitazar (Pargluva), the first of a new class of antidiabetic agents called glitazars, after an FDA panel endorsed it in 2005. However, researchers then reported an increase of cardiovascular conditions including heart attack and stroke and a possible increased incidence of cancer in test subjects. Problems including cardiovascular side effects and lack of effectiveness have prompted discontinuation of several other glitazars that were under development, but some are still being researched.
  
  
• Selective PPAR modulators. The goal of the non- thiazolidinedione metaglidasen is to control glucose and triglycerides without causing edema or weight gain. Other PPAR modulators being assessed in humans include PN2034 and harmine.
  
  
• Anti-inflammatories. Some evidence suggests that chronic inflammation may be a factor in development of insulin resistance and type 2 diabetes. Researches are testing whether the nonsteroidal anti-inflammatory drugs (NSAIDs) salsalate or rofecoxib and anti-inflammatory monoclonal antibodies such as XOMA 052 may help. Researchers reported in 2007 that a short-term anti-inflammatory drug combination reversed new-onset type 1 diabetes in mice, and more research is planned.
  
  
• Cardiovascular drugs. For example, the cholesterol drug colesevelam is being assessed for possible glucose-lowering effects in type 2 diabetes, and an investigational antihypertensive called AD-4833-536 is being assessed as a way to control glucose and blood pressure in people with type 2 diabetes and high blood pressure.
  
  
• Cancer-fighting drugs. Angiogenesis inhibitors such as prinomastat are being studied as a way to slow the destruction of pancreatic beta cells in type 1 diabetes.
  
  
• Gene regulators. A protein called calcineurin, recently found to regulate 10 genes linked to diabetes, and a related protein called NFAT are being investigated for possible pharmaceutical roles.
  
  
• PBA and TUDCA. Research on animals suggests that chemicals known as PBA (4-phenyl butyric acid) and TUDCA (taurine-conjugated derivative) may improve levels of glucose and insulin and help fight fatty liver disease, a common condition in people with type 2 diabetes.
  
  
• Vitamins. Researchers are examining whether vitamin D can prevent type 1 diabetes in children.
  
  
• Carnitine. Scientists are studying whether oral supplements of carnitine, an amino acid derivative, may reduce hypoglycemia in children with type 1 diabetes.
  
  
• Herbs and foods. Many herbs, spices, nuts and other foods are being investigated for possible glucose-controlling roles.

Researchers are also working on drugs to treat complications such as diabetic retinopathy and diabetic kidney disease.

Although pharmaceutical development is a long and complicated process, with frequent setbacks, scientists are reporting many encouraging results from laboratory studies and clinical trials.