The ticket into this trial is a number most families have already seen on a printout: C-reactive protein, the ordinary blood marker a GP orders when something looks inflamed. In Cambridge, people with early Parkinson's disease need an hsCRP above 1 mg/L to qualify, along with a diagnosis under five years old and a Hoehn and Yahr stage of 2 or below. Thirty-six of them will take a tablet twice a day for six months.
The tablet is dapansutrile. It is aimed at one component of the immune system, the NLRP3 inflammasome, the assembly inside immune cells that switches on interleukin-1 beta. Think of a smoke alarm wired into every immune cell. Useful when there is a fire. Exhausting when it keeps going off in a quiet house.
The trial is called DAPA-PD, registered as NCT07157735, sponsored by Cambridge University Hospitals NHS Foundation Trust and led by Dr Caroline Williams-Gray. It is randomised, placebo-controlled and quadruple-masked, two people on drug for every one on placebo. Dosing starts at 500 mg twice daily for four weeks, then 1,000 mg twice daily. After the six-month blinded phase there is an optional six-month open-label phase in which everyone can take the active drug.
Read the primary endpoint carefully, because it tells you what this study is for: the number of adverse events recorded during the six-month double-blind period. This is a safety and tolerability trial. Brain inflammation measured by PET-MR with the TSPO ligand [18F]-DPA-714, blood CRP and blood interleukin-1 beta sit in the secondary column, with the imaging compared between baseline and week 23.
The reason to watch it anyway is what happened in the same clinic, with the same investigators, last winter.
AZA-PD tested azathioprine, a broad immunosuppressant used for decades in rheumatoid arthritis. Sixty-six people with early Parkinson's were randomised, 32 to azathioprine at 2 mg/kg daily and 34 to placebo, for twelve months. At twelve months the mean change in the MDS-UPDRS gait-axial score in the off-state was 0.54 points in the azathioprine group and 0.13 in the placebo group, effect size 0.438, 95% CI -0.694 to 1.57, p=0.78. The results were presented at the AD/PD conference in April 2025 and published in The Lancet Neurology in the January 2026 issue.
That is a clean miss on the thing the trial set out to measure, reported by the people who ran it. Secondary motor measures looked more encouraging, which is exactly the kind of signal that a 66-person trial cannot settle.
So the logic shifts from turning the whole immune system down to turning one switch off. Dapansutrile, developed by Olatec Therapeutics, has been through human trials in acute gout, heart failure, COVID-19 and melanoma, and the trial registry's plain English summary states it has been shown to be safe for use in people in those studies. In animal models, the registry entry says, it protected against inflammation in the brain and prevented loss of dopamine cells. Animal models are animal models. Mice have been cured of Parkinson's many times.
The drug is not licensed for any condition in any country. Nobody should be ringing a pharmacy about it, and the registry says so plainly.
For a reader whose parent has Parkinson's, here is the shape of it. This trial will not report whether dapansutrile slows the disease. Thirty-six people, six months, a safety primary endpoint: that is a gate, not a verdict. If the gate opens, the team has said it hopes the results will show whether a larger phase 3 study is warranted.
And for this paper's readers in particular, one more boundary. DAPA-PD recruits people in the movement-symptom phase of Parkinson's, and its listed outcomes are safety, brain imaging and blood markers. It will say nothing directly about the thinking and memory changes that bring some families to Parkinson's disease dementia years later. The hope behind neuroinflammation work is that those two stories are connected. The trial does not test that connection.
The registries disagree slightly on where things stand, which is the sort of small untidiness worth reporting. ClinicalTrials.gov, last verified in July 2025, lists a study start date of 31 October 2025 and 36 participants. The UK registry entry, ISRCTN16806940, lists the study as recruiting, funded by Cure Parkinson's Trust, run from the Cambridge Clinical Trials Unit, with the overall study ending on 31 March 2027.