A new study published in “The Lancet Neurology” investigates whether azathioprine, a common immunosuppressant, could represent a breakthrough in slowing the progression of Parkinson’s Disease (PD).
For decades, PD treatment has focused almost exclusively on managing symptoms by replacing dopamine. However, researchers are increasingly looking at the immune system as a key player in how the disease progresses. The AZA-PD trial, led by IMMUPARKNET member Professor Caroline Williams-Gray along with a team of researchers who also are members of IMMUPARKNET (Julia Greenland, Marta Camacho, Alexander Peattie, Jonathan Holbrook, Kirsten Scott), explores this frontier by testing the efficacy of azathioprine in patients with early-stage PD.
The rationale behind the study is based on growing evidence that the peripheral immune system and chronic inflammation contribute to the death of dopaminergic neurons. By modulating immune response, scientists hope to move from “symptoms management” to “disease modification” — actually slowing down the neurodegenerative process.
The AZA-PD trial was a Phase 2, randomized, double-blind, placebo-controlled study focusing on:
- Participants: patients aged 50–80, diagnosed with PD within the last three years
- Treatment: a daily dose of azathioprine (2 mg/kg) versus a placebo over a 12-month period
- Goal: measuring the change in motor disability (using the MDS-UPDRS Part III scale) while patients were in their “off” state
Key Findings
The trial sought to determine if suppressing the peripheral immune response could translate into better clinical outcomes.
- Motor Impact: researchers focused on whether the drug could stabilize motor scores, particularly regarding gait and axial stability, compared to the placebo group
- Safety & Toll: a critical aspect of the study was monitoring the safety profile of azathioprine in an older population, specifically looking for side effects like infections or blood count changes
While larger trials are needed to confirm long-term benefits, the AZA-PD study provides a vital “proof-of-concept”, reinforcing the idea that PD is not just a brain-isolated condition but one deeply connected to the body’s systemic immune health. Repurposing existing drugs like azathioprine could significantly speed up the search for a way to halt the disease, offering hope to millions of patients who currently rely on treatments that only mask the symptoms.
Reference
Williams-Gray CH, Greenland JC, et al.
“Azathioprine for the treatment of early Parkinson’s disease (AZA-PD): a randomised, double-blind, placebo-controlled, proof-of-concept, phase 2 trial”.
The Lancet Neurology. 2026;25(1):45–56.
