AriBio reports early Phase 2a results for DLB drug AR1005

AriBio said interim data from a Phase 2a trial in South Korea showed AR1005 improved cognitive fluctuations in dementia with Lewy bodies and produced favorable qEEG signals at Week 20. The company is preparing for a pre-IND meeting with the FDA as it weighs a global Phase 2/3 program.

Why it matters: - Dementia with Lewy bodies has limited treatment options, and symptoms can include cognitive decline, cognitive fluctuations, visual hallucinations and parkinsonism. - AriBio’s interim data suggest AR1005 may help with one of DLB’s most clinically important symptoms: cognitive fluctuation. - The findings also point to a possible biological signal on quantitative EEG, which may support the drug’s proposed mechanism.

What happened: - AriBio reported interim results from its ongoing Phase 2a trial of AR1005 in patients with dementia with Lewy bodies. - The study, NCT06537076, is being run at Severance Hospital in Korea. - The interim analysis included 31 participants from a trial expected to enroll 60 patients. - The company presented the findings at the Alzheimer’s Association International Conference 2026 in London.

The details: - AR1005 is an oral fixed-dose combination of lamotrigine and rivastigmine. - Lamotrigine inhibits voltage-gated sodium channels and is designed to reduce excessive excitatory neurotransmission. - Rivastigmine is an approved treatment for cognitive symptoms. - The trial is testing whether targeting neuronal hyperexcitability can reduce cognitive and neuropsychiatric symptoms in DLB. - At Week 20, AR1005 showed a 1.15-point treatment difference on the Mayo Fluctuations Scale versus placebo, in favor of AR1005. - The result met statistical significance, with a 95% confidence interval of -2.17 to -0.12 and p=0.030. - The Mayo Fluctuations Scale measures cognitive fluctuations, and lower scores mean less severe symptoms. - qEEG findings showed lower theta-to-beta ratios with AR1005, which is associated with less EEG slowing in DLB. - The theta-to-beta ratio treatment difference was -3.34 globally, with p=0.039. - Region-specific qEEG results were also favorable in the central region at -3.41 with p=0.042 and in the occipital region at -3.75 with p=0.045. - AR1005 showed a 0.46-point treatment difference in favor of the drug on the Clinical Dementia Rating–Sum of Boxes at Week 20, but the result was not statistically significant. - Numerical trends also favored AR1005 on the Korean Mini-Mental State Examination and the Caregiver-Administered Neuropsychiatric Inventory. - Final efficacy and safety results will be assessed after the full study is complete.

Between the lines: - The interim readout gives AriBio an early signal on both symptoms and physiology, but the sample size is still small and the company has not released full safety data. - The qEEG results may matter because they align with the program’s hypothesis that neuronal hyperexcitability is part of the disease process. - The mixed picture on broader clinical endpoints suggests the final dataset will be important before stronger conclusions are drawn. - The company’s next steps point to a larger development strategy, not just a single-study readout.

What's next: - AriBio said it has begun preparing for a pre-IND meeting with the FDA. - The company plans to use the complete dataset to define the design and endpoints of a global Phase 2/3 program. - Final efficacy and safety results will come after all 60 participants finish the study.

The bottom line: - AR1005 produced an encouraging early signal in DLB, especially for cognitive fluctuations, but the case for the drug still depends on full trial results.