Ambroxol to Slow Progression in Parkinson Disease

This is a UK only clinical trial in patients with Parkinson's disease (PD) of a drug called ambroxol hydrochloride, which is an already licensed drug for the treatment of respiratory conditions (such as a common cold) in many European countries. The aim of this trial is to find out whether ambroxol hydrochloride can slow down the progression of Parkinson's disease and to evaluate it's safety and tolerability.

This is a 104-week, randomized, double-blind, multi-centre, parallel group, placebo-controlled clinical trial of ambroxol hydrochloride in patients with PD, with a 26-week open-label extension phase. Participants will undergo screening to evaluate their eligibility to participate in the trial. All eligible participants will be randomised to receive either ambroxol hydrochloride (420mg) or it's matching placebo in a 1:1 ratio three times a day for 104 weeks, including a 2-week dose escalation period. Once the end of the blinded treatment has been reached, all participants will enter the open-label extension phase and will receive ambroxol hydrochloride (420mg) three times a day for 26 weeks, including a 2-week dose escalation period. All clinical staff, study investigators, and participants will be blinded to study assignments throughout the entirety of the trial. There will be an optional sub-study including 106 participants in which a cerebrospinal fluid (CSF) sample will be taken on two occasions via a Lumbar Puncture procedure to measure ambroxol drug levels, assess whether the glucocerebrosidase enzyme has been stimulated and the levels of other substances thought to be associated with the development of PD and confirm whether the study drug has penetrated the cerebrospinal fluid and Central Nervous System.