The type-2 diabetes drug exenatide also has exhibited symptomatic benefits in Parkinson's disease, in a prospective randomized interventional trial [1], with persistent motor and cognitive benefits which suggest possible disease modification. Exenatide is not a thiazolidinedione ("glitazone"), and its concomitant use should be accounted for in the glitazone study, to avoid skewed results.
1: Aviles-Olmos I, Dickson J, Kefalopoulou Z, Djamshidian A, Kahan J, Ell P,
Whitton P, Wyse R, Isaacs T, Lees A, Limousin P, Foltynie T. Motor and cognitive
advantages persist 12 months after exenatide exposure in Parkinson's disease. J
Parkinsons Dis. 2014;4(3):337-44. doi: 10.3233/JPD-140364. PubMed PMID: 24662192.