Table 2. Clinical studies evaluating bile acids in neurodegenerations.

Biliary acid	Study design	Number of patients	Disease	Dose	Route	Main results
UDCA	Randomized, non-controlled	18	Amyotrophic lateral sclerosis	15, 30 or 50 mg/kg/day during 4 weeks	Orally	-Excellent safety and tolerability -Cerebrospinal fluid penetration in a dose-dependent manner
UDCA	Double-blind, placebo-controlled, randomized, crossover, single center, phase III trial	63 (16 analyzed)	Amyotrophic lateral sclerosis	3.5 g/140 ml/day for 3 months	Orally (solubilized)	The rate of progression (assessed by the Appel ALS rating scale) was significantly lower in patients treated with UDCA compared to placebo
TUDCA	Double-blind placebo- controlled, randomized, multi-center, phase II trial	34 (29 analyzed)	Amyotrophic lateral sclerosis	1 g day for 54 weeks	Orally	Deterioration of function (assed by the ALS Functional Rating Scale Revised) was significantly slower in TUDCA group compared to placebo

ALS: Amyotrophic lateral sclerosis, UDCA: Ursodeoxycholic acid, TUDCA: Tauroursodeoxycholic acid