Table 2.

Recent clinical trials for disease-modification in PD.

Drug name	Mechanism of action	Disease stage	Dose and administration route	Sample size	Primary outcome	Results
Exenatide (47)	Antihyperglycemic; glucagon-like peptide 1 (GLP-1) receptor agonist	Moderate PD	2 mg or placebo, subcutaneous injections	62	MDS-UPDRS, motor scores (part 3) in the practically defined off-medication state	Mild improvement in the intervention group in comparison to placebo difference of −3.5 points (−6.7 to −0.3; p = 0.0318)
Nilotinib (48)	BCR-ABL inhibitor used for treatment of leukemia	Cohort 1—moderate to advanced PD Cohort 2—early/de novo PD	150 or 300 mg; oral	76	Safety and Tolerability; MDS-UPDRS, motor scores part III	Drug was well-tolerated. MDS-UPDRS-part III was worse in the Nilotinib 300 mg group
Pioglitazone (49)	Antihyperglycemic, inhibit the activation of microglia and astrocytes and production of pro-inflammatory cytokines and nitric oxide	Early PD diagnosed within 5 years	15, 45 mg/day, or placebo; oral	210	Total UPDRS score	Negative results
Transdermal Nicotine NIC-PD (NCT01560754)	Agonist of nicotine receptor, modulate dopaminergic function	Early PD up to 18 months of diagnosis	7 or 14 mg nicotine titrated up to 28 mg, or placebo; transdermal	160	UPDRS score (parts 1 to 3) Parkinson's Disease Questionnaire−8 (PDQ-8)	Unpublished
Isradipine (50) STEADY-PD III	Dihydropyridine calcium-channel blocker, used for hypertension	Early PD not requiring symptomatic treatment	5 mg BID or placebo; oral	336	UPDRS score (parts 1 to 3)	Negative results
Inosine (51) SURE-PD3	Urate precursor used for urate elevation	Early PD not requiring symptomatic treatment	Inosine to produce mild elevation of urate; inosine to produce moderate elevation; or placebo	75	Safety and Tolerability; Elevation of urate assessed serially in serum in cerebrospinal fluid	Negative results

PDQ, Parkinson's Disease Questionnaire; UPDRS, Unified Parkinson Disease Rating Scale.