Study phase II.
A drug normally used for diabetes, called Pioglitazone, is to undergo clinical trials in people with early Parkinson’s Disease. The aim is to determine whether it can slow clinical decline over a 44 week period. Pioglitazone is being given in 15mg and 45 mg dosages. Pioglitazone is an FDA approved drug for the treatment of diabetes. It has not been previously studied in people with Parkinson's Disease. Pioglitazone is marketed in tablet form as Actoplus, Duetact, and Actos. It acts primarily by decreasing insulin resistance. Neither source for the clinical trials provides a rationale for the use of Pioglitazone in Parkinson's Disease. Insulin resistance has never been shown to cause Parkinson's Disease. Preliminary studies have been carried out using Pioglitazone on animals concerning Parkinson's Disease. However, the circumstances of those studies are not comparable with idiopathic Parkinson's Disease in humans.
http://clinicaltrials.gov/ct2/show/NCT01280123
http://www.pdtrials.org/en/browse/all/view/317