Fecal Microbiota Transplantation Had No Benefit as Parkinson Disease Treatment

Fecal microbiota transplantation (FMT) was associated with alteration in gut microbiota (GMB) but no clinically meaningful improvements in symptoms vs placebo for people with Parkinson disease (PD), according to results of a clinical trial (NCT04854291) sponsored by the Helsinki University Central Hospital and published in JAMA Neurology. Additionally, participants treated with placebo showed increased levodopa-equivalent daily dose (LEDD; a total of daily parkinsonian medications) and clinically meaningful improvements in some cognitive and gastrointestinal outcomes at 6 months, while FMT-treated participants showed a greater incidence of gastrointestinal adverse events (AEs). These findings contrast with preclinical studies that demonstrated efficacy for FMT as a treatment for PD.

The randomized, placebo-controlled, double-blind trial was conducted at 4 hospitals in Finland and included 45 patients with PD, aged 35 to 75 years, who were randomized 2:1 to receive either FMT or placebo via colonoscopy. The primary endpoint was change in Movement Disorder Society Unified Parkinson's Disease Rating Scale (MDS-UPDRS) parts I-III at 6 months. Secondary outcomes included multiple motor and nonmotor symptoms assessments, along with safety as measured by incidence of AEs.

• At 6 months, there was no significant difference between the placebo and FMT groups in the primary outcome (.97 points; 95% CI, 5.10 to -7.03; P=.75).
• At 6 months, the placebo group showed clinical improvements in Montreal Cognitive Assessment (MoCA) score, Irritable Bowel Severity Scoring System (IBSSSS) score, and Wexner constipation score.
• Participants treated with placebo showed a faster dopaminergic medication increase (LEDD).
• At 12 months, participants treated with FMT showed significantly increased NonMotor Symptoms Scale score.
• Gastrointestinal AEs were more frequent in participants treated with FMT vs those treated with placebo (53% vs 7%; P=.003)
• Microbiota changes were more pronounced after FMT but varied by donor.
• Dysbiosis status was reversed more frequently in the placebo group.

The study authors note, “This negative trial may give important insights to design future improved and hopefully successful trials of this intervention.”