Finnish faecal transplant trial

The research record

This is the project's file for this landmark, as written and checked. Sources are listed at the end; anything not yet confirmed is marked "Not yet verified".

Who

Filip Scheperjans (Helsinki University Hospital), Perttu Arkkila and colleagues at four Finnish hospitals. Published in JAMA Neurology 2024;81:925–938 (DOI 10.1001/jamaneurol.2024.2305). Registered as NCT04854291.

What happened

Patients aged 35 to 75, Hoehn-Yahr stage 1 to 3, with a stool test showing "dysbiosis" (an unbalanced gut microbiome), were screened (229 screened). 48 were randomised 2:1 to donor stool or placebo (own stool), given once by colonoscopy; 47 were treated and 45 analysed (30 donor stool, 15 placebo, from the sex counts in the abstract). The trial ran from November 2020 to June 2023 with 12 months of follow-up.

The primary measure was the change in MDS-UPDRS parts I to III (part III off medication) at six months. It did not differ between groups (0.97 points, 95% CI -5.10 to 7.03, P = 0.75). Stomach side effects were more frequent with donor stool (16 of 30 versus 1 of 15, P = 0.003). The placebo group had a stronger rise in dopamine medication and better results on some secondary measures. Gut bacteria changed more after donor stool, but differed by donor, and the "dysbiosis" status reversed more often in the placebo group. The authors concluded that the transplant was safe but gave no clinically meaningful gain.

Why it moved us toward a cure

It tests the idea from mouse work (landmark 56) that gut bacteria drive the disease. The null result, with the Warsaw trial (landmark 262), argues against a single colonoscopic transplant as a treatment. It differs from the positive Belgian trial (landmark 139) in route (colonoscopy versus nasojejunal tube) and in selecting patients by dysbiosis. Neither tested whether decline is slowed.

Outcome

Dead end for a single colonoscopic transplant as a symptom treatment. It is not a test of disease slowing, and the authors say modified transplants, bowel cleansing or donor matching may still be worth studying.

Sources

• Scheperjans et al., JAMA Neurol 2024, DOI 10.1001/jamaneurol.2024.2305 · PMC11287445 (abstract read via Europe PMC)
• ClinicalTrials.gov NCT04854291 (registry shows 51 enrolled and primary completion 27 Dec 2022; the paper reports 48 randomised)
• Not yet verified: the full text (group sizes are inferred from the abstract's sex percentages; 12-month results; adverse-event detail); the difference between the registry's 51 and the paper's 48.