Ambroxol as a Treatment for Parkinson's Disease Dementia

Summary

The present study will test the hypothesis that the medication Ambroxol is safe and well tolerated and will improve cognitive and motor symptoms of Parkinson's Disease Dementia (PDD). Ambroxol has been shown to raise the levels of the enzyme beta-glucocerebrosidase resulting in lower the levels of the protein alpha-synuclein, both of which have been shown to improve cognition in mouse models. This will be a 52 week trial of Ambroxol in 75 individuals with PDD. Participants will undergo clinical, neuropsychological and neuroimaging assessment throughout the study to assess changes.

Timeline

Start

2015-11

Primary completion

2025-12

Completion

2025-12

Outcome

Missed primary endpoint

paper There was no evidence to suggest differences between groups on primary or secondary outcomes. PMID 40587145 ↗

paper However, the effect of ambroxol on cognition was not confirmed. PMID 40587145 ↗

Publications

• Background Lang AE, Obeso JA. Challenges in Parkinson's disease: restoration of the nigrostriatal dopamine system is not enough. Lancet Neurol. 2004 May;3(5):309-16. doi: 10.1016/S1474-4422(04)00740-9.
• Background Balducci C, Pierguidi L, Persichetti E, Parnetti L, Sbaragli M, Tassi C, Orlacchio A, Calabresi P, Beccari T, Rossi A. Lysosomal hydrolases in cerebrospinal fluid from subjects with Parkinson's disease. Mov Disord. 2007 Jul 30;22(10):1481-1484. doi: 10.1002/mds.21399.
• Background Gegg ME, Burke D, Heales SJ, Cooper JM, Hardy J, Wood NW, Schapira AH. Glucocerebrosidase deficiency in substantia nigra of parkinson disease brains. Ann Neurol. 2012 Sep;72(3):455-63. doi: 10.1002/ana.23614.
• Background Sardi SP, Clarke J, Viel C, Chan M, Tamsett TJ, Treleaven CM, Bu J, Sweet L, Passini MA, Dodge JC, Yu WH, Sidman RL, Cheng SH, Shihabuddin LS. Augmenting CNS glucocerebrosidase activity as a therapeutic strategy for parkinsonism and other Gaucher-related synucleinopathies. Proc Natl Acad Sci U S A. 2013 Feb 26;110(9):3537-42. doi: 10.1073/pnas.1220464110. Epub 2013 Jan 7.
• Background Malerba M, Ragnoli B. Ambroxol in the 21st century: pharmacological and clinical update. Expert Opin Drug Metab Toxicol. 2008 Aug;4(8):1119-29. doi: 10.1517/17425255.4.8.1119.
• Background Maegawa GH, Tropak MB, Buttner JD, Rigat BA, Fuller M, Pandit D, Tang L, Kornhaber GJ, Hamuro Y, Clarke JT, Mahuran DJ. Identification and characterization of ambroxol as an enzyme enhancement agent for Gaucher disease. J Biol Chem. 2009 Aug 28;284(35):23502-16. doi: 10.1074/jbc.M109.012393. Epub 2009 Jul 3.
• Background Luan Z, Li L, Higaki K, Nanba E, Suzuki Y, Ohno K. The chaperone activity and toxicity of ambroxol on Gaucher cells and normal mice. Brain Dev. 2013 Apr;35(4):317-22. doi: 10.1016/j.braindev.2012.05.008. Epub 2012 Jun 7.
• Background Laoag-Fernandez JB, Fernandez AM, Maruo T. Antenatal use of ambroxol for the prevention of infant respiratory distress syndrome. J Obstet Gynaecol Res. 2000 Aug;26(4):307-12. doi: 10.1111/j.1447-0756.2000.tb01327.x.
• Background Luerti M, Lazzarin A, Corbella E, Zavattini G. An alternative to steroids for prevention of respiratory distress syndrome (RDS): multicenter controlled study to compare ambroxol and betamethasone. J Perinat Med. 1987;15(3):227-38. doi: 10.1515/jpme.1987.15.3.227.
• Background Wauer RR, Schmalisch G, Hammer H, Buttenberg S, Weigel H, Huth M. Ambroxol for prevention and treatment of hyaline membrane disease. Eur Respir J Suppl. 1989 Mar;3:57S-65S.
• Background Schmalisch G, Wauer RR, Bohme B. Changes in pulmonary function in preterm infants recovering from RDS following early treatment with ambroxol: results of a randomized trial. Pediatr Pulmonol. 1999 Feb;27(2):104-12. doi: 10.1002/(sici)1099-0496(199902)27:23.0.co;2-t.
• Background Narita A, Kubota N, Takayama R, Takahashi Y, Maegaki Y, Suzuki Y, & Ohno K. Chaperone therapy for neuronopathic Gaucher disease. Molecular Genetics and Metabolism, 108(2): S69, 2013.
• Background Narita A, Zhuo L, Higaki K, Togawa M, Maegaki Y, Nanba E, Suzuko Y, Ohno K: Chemical chaperone therapy for neuropathic Gaucher disease. In 12th International Child Neurology Congress and the 11th Asian and Oceanian Congress of Child Neurology Brisbane. QLD Australia: Developmental Medicine and Child Neurology (54): 50-51, 2012.
• Background Zimran A, Altarescu G, Elstein D. Pilot study using ambroxol as a pharmacological chaperone in type 1 Gaucher disease. Blood Cells Mol Dis. 2013 Feb;50(2):134-7. doi: 10.1016/j.bcmd.2012.09.006. Epub 2012 Oct 22.
• Silveira CRA, Coleman KKL, Borron K, Tirona RG, Rupar CA, Zou G, Hegele RA, Wellington C, Stukas S, Finger EC, Bartha R, Morrow SA, Wells JL, Borrie MJ, Mahuran D, MacDonald PA, Jenkins ME, Jog MS, Dresser G, Fox S, Camicioli R, Feagan B, Mendonca DA, Mayich M, Sharma MD, Pandey SK, Pasternak SH. Ambroxol as a Treatment for Parkinson Disease Dementia: A Randomized Clinical Trial. JAMA Neurol. 2025 Jun 30;82(8):797-807. doi: 10.1001/jamaneurol.2025.1687. Online ahead of print.
• Silveira CRA, MacKinley J, Coleman K, Li Z, Finger E, Bartha R, Morrow SA, Wells J, Borrie M, Tirona RG, Rupar CA, Zou G, Hegele RA, Mahuran D, MacDonald P, Jenkins ME, Jog M, Pasternak SH. Ambroxol as a novel disease-modifying treatment for Parkinson's disease dementia: protocol for a single-centre, randomized, double-blind, placebo-controlled trial. BMC Neurol. 2019 Feb 9;19(1):20. doi: 10.1186/s12883-019-1252-3.

Drugs

Evaluation	Drug	Modality	Dose	Route
Subject	Ambroxol	Small molecule	525 mg	—
Subject	Ambroxol	Small molecule	1050 mg	—

Indications