The Lancet has issued an expression of concern notice over a phase 3 trial testing exenatide as a disease-modifying therapy for Parkinson’s disease, following findings from a regulatory inspection at King’s College Hospital, London, one of the study sites.

In a notice published online [link here], the journal’s editors said they had been informed by the study’s corresponding author, Professor Tom Foltynie, of the findings of the inspection, which was part of a broader review.

According to the editors, the inspection identified “department-wide concerns relating to trial conduct, oversight and governance, including findings classified by regulators as critical and major”.

Pending the outcome of investigations by King’s College Hospital NHS Foundation Trust and assessments of whether the inspection findings could affect the study data or conclusions, The Lancet said it was issuing an Expression of Concern.

“We will update this notice as soon as we have further information.”

In February 2025, the journal published an article on the results of a Phase 3 study of exenatide – a type 2 diabetes drug that had previously shown promise in both lab studies and early-stage trials for slowing the progression of Parkinson’s. 

However, the trial, led by Dr Nirosen Vijiaratnam of UCL Queen Square Institute of Neurology and colleagues, found no evidence that exenatide slowed disease progression compared with placebo.

At 96 weeks, OFF-medication scores had increased (worsened) by 5.7 points (mean) in the exenatide group and by 4.5 points in the placebo arm (adjusted coefficient for the effect of exenatide 0.92; p=0.47). 

Exenatide also failed to show any benefit on a number of secondary outcomes, including ON-medication state scores, non-motor features, quality of life, and changes in levodopa equivalent daily doses.

the limbic has contacted King’s College Hospital for comment.