Ambroxol to Slow Progression in Parkinsons Disease: A Phase IIIA multi-centre randomised placebo-controlled trial (ASPro-PD)

A daily 1260mg dose of the cough medicine ambroxol is being tested against placebo in 90-week double-blind trial to see if it can slow Parkinson’s disease progression. Parkinson’s disease currently has no treatment that stops or slows its underlying neurodegeneration. Existing therapies manage symptoms but lose effectiveness as the disease advances. Ambroxol, an over-the-counter mucolytic, also raises levels of the enzyme glucocerebrosidase, which is deficient in many Parkinson’s patients and linked to toxic protein clumps in the brain. This trial directly tests whether boosting that enzyme can alter the disease’s course. If ambroxol proves effective, it would become the first readily available, low-cost oral drug to slow Parkinson’s progression—not just mask symptoms. That could delay disability, reduce care needs, and extend independent living for hundreds of thousands of people. The trial also includes an open-label extension phase, giving all participants access to the drug and generating long-term safety data. Even a modest slowing of progression would transform how the condition is managed, shifting from symptom control to disease modification.