CAMBRIDGE, Mass., July 28, 2026
ProMIS Neurosciences Inc. announced positive blinded six-month interim safety and biomarker data from the ongoing PRECISE-AD Phase 1b clinical trial evaluating PMN310 in patients with mild cognitive impairment due to Alzheimer’s disease or mild Alzheimer’s disease. The interim analysis included 136 participants and demonstrated a favorable safety profile across all genetic groups, including high-risk APOE4 homozygotes, with no cases of amyloid-related imaging abnormalities-edema (ARIA-E) reported at the data cutoff. The study also showed 4.4% total ARIA, consisting exclusively of mild, asymptomatic ARIA-H (microhemorrhages), while no treatment-related serious adverse events or drug-related discontinuations were observed. The randomized, double-blind, placebo-controlled study remains ongoing, with 12-month topline efficacy and safety results expected in the first quarter of 2027.
Early Biomarker Trends Suggest Target Engagement
The blinded interim assessment also revealed encouraging movement in Alzheimer’s disease biomarkers, providing early evidence consistent with PMN310 target engagement. According to the company, 68.5% of participants experienced reductions from baseline in plasma pTau217, while 62.5% showed decreases in CSF MTBR-tau243, two biomarkers widely recognized for monitoring Alzheimer’s disease progression. Although treatment assignments remain blinded and these findings are not considered evidence of clinical efficacy, the observed biomarker trends were directionally consistent with the study’s 3:1 active treatment-to-placebo randomization. PMN310 is designed to selectively bind toxic amyloid-beta oligomers while avoiding interaction with amyloid plaques and vascular deposits, a differentiated mechanism intended to preserve therapeutic activity while minimizing the ARIA risks commonly associated with currently available plaque-targeting Alzheimer’s therapies.
Differentiated Approach May Address Key Treatment Limitation
ProMIS believes the interim findings support its strategy of developing an oligomer-selective monoclonal antibody capable of addressing one of the greatest challenges in Alzheimer’s treatment—amyloid-related imaging abnormalities (ARIA). Chief Executive Officer Neil Warma said the absence of ARIA-E, combined with the favorable safety profile and encouraging biomarker trends, reinforces the company’s hypothesis that selectively targeting toxic amyloid oligomers may provide the benefits of amyloid-directed therapy without the safety burden associated with plaque-binding antibodies. External expert Dr. Will Mantyh of the University of Minnesota noted that ARIA remains one of the primary barriers to prescribing current Alzheimer’s therapies and described a treatment profile with no ARIA-E and favorable biomarker movement as potentially transformative for both physicians and patients if confirmed in future analyses.
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Topline Phase 1b Results Expected in Early 2027
The PRECISE-AD study has completed enrollment of 144 patients across multiple dosing cohorts and is evaluating the safety, tolerability, pharmacokinetics, biomarkers, and clinical outcomes of intravenous PMN310 over a 12-month treatment period. The investigational therapy previously received FDA Fast Track Designation and represents ProMIS Neurosciences’ lead Alzheimer’s disease program. Beyond Alzheimer’s disease, the company’s proprietary EpiSelect™ discovery platform is being applied to develop therapies targeting toxic misfolded proteins associated with several neurodegenerative diseases, including Parkinson’s disease, amyotrophic lateral sclerosis (ALS), frontotemporal dementia (FTD), and multiple system atrophy (MSA). With unblinded 12-month topline data expected in Q1 2027, ProMIS aims to determine whether the promising safety profile and early biomarker improvements translate into meaningful clinical benefits for patients living with Alzheimer’s disease.
Source: ProMIS Neurosciences, press release
