Aribio Confirms Improvement in Cognitive Fluctuations in Interim Analysis of Phase 2 Lewy Body Dementia Treatment Trial

Presented at AAIC 2026
Statistically Significant Improvements Observed in Cognitive Fluctuations and Quantitative EEG Markers
Global Phase 2/3 Trial Design Initiated

On the 16th, Aribio announced that in the interim analysis of the domestic Phase 2a clinical trial for its investigational treatment for Lewy body dementia, ‘AR1005,’ improvements were observed in both cognitive fluctuations and quantitative electroencephalography (EEG) indicators. The study results were presented at the Alzheimer’s Association International Conference (AAIC 2026), which took place in London, UK, from June 12 to 15, local time.

From June 12 to 15 (local time), a representative from Aribio presented the results of the Phase 2a clinical trial at the Alzheimer's Association International Conference (AAIC 2026) held in London, United Kingdom. Aribio

Lewy body dementia is the second most common degenerative dementia after Alzheimer's disease. It is characterized by a combination of symptoms such as cognitive impairment, fluctuations in cognition, and Parkinsonism. Currently, however, no therapeutic agent has been approved with the disease itself as an indication.

AR1005 is an oral combination therapy being developed by Aribio, following its Alzheimer’s treatment ‘AR1001.’ It aims to improve cognitive function by controlling neuronal hyperexcitability in patients with Lewy body dementia.

The ongoing trial is being conducted at Severance Hospital with a total of 60 patients. The interim analysis included data from 31 patients, which is roughly half of the target enrollment. According to the company, results showed a statistically significant improvement in cognitive fluctuations—a representative symptom of Lewy body dementia. The adjusted mean score on the Mayo Fluctuations Scale, which assesses cognitive fluctuations, was 0.77 in the AR1005 group, significantly lower than the control group’s score of 1.92.

Similar results were found in quantitative EEG, which objectively evaluates brain function. The theta/beta ratio, an indicator reflecting cognitive decline, showed a significant decrease in the AR1005 group compared to the control group across the entire brain, as well as in the central and occipital regions. The company emphasized the significance of observing improvements in both patient-perceived symptoms and objective biomarkers.

On the CDR-SB, which evaluates cognitive and daily living functions, the AR1005 group showed an improvement of 0.46 points over the control group at the 20-week dosing mark. Compared to baseline, the control group worsened by 0.34 points, whereas the AR1005 group improved by 0.16 points. Consistent improvement trends were also observed in the K-MMSE and CGA-NPI in the AR1005 group, but statistical significance could not be established due to the limited patient numbers.

Professor Yebyeong Seok of Severance Hospital’s Department of Neurology stated, “Statistically significant improvements were confirmed in cognitive fluctuations and quantitative EEG indicators, and other clinical indicators also showed consistent improvement, serving as early evidence for the therapeutic potential of AR1005.” Aribio CEO Jeong Jaejun said, “Based on these interim analysis results, we will further detail our global Phase 2/3 trial design and regulatory strategy to accelerate development.”

This analysis was conducted as an interim assessment prior to the completion of full patient enrollment. Final efficacy and safety will be determined after the trial is completed for all 60 patients.

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