ProMIS Neurosciences has announced positive blinded six-month interim safety and biomarker results from its 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 patients and demonstrated a favourable safety profile across all genotypes. No cases of Amyloid-Related Imaging Abnormalities-Edema (ARIA-E) were reported as of the data cutoff date, while the overall incidence of ARIA was 4.4 percent, consisting entirely of mild, asymptomatic ARIA-H cases. The study also reported no treatment-related serious adverse events or drug-related discontinuations.

The favourable safety profile was observed even among patients carrying the APOE4 genotype, a group considered at higher risk and often underserved by currently approved amyloid-targeting therapies. The study population included 61 percent APOE4 carriers, of whom 11 percent were homozygotes.

Blinded interim biomarker analyses also indicated early, directionally consistent reductions in disease-related biomarkers. Approximately 68.5 percent of patients showed declines in plasma pTau217, while 62.5 percent recorded reductions in CSF MTBR-tau243, compared with expected increases based on the natural progression of the disease. The company noted that these observations remain blinded and are not a confirmation of clinical efficacy.

PMN310 is designed to selectively target toxic amyloid-beta oligomers while avoiding amyloid plaques, a differentiated mechanism intended to reduce the risk of ARIA commonly associated with existing plaque-binding therapies.

The PRECISE-AD study is a randomised, double-blind, placebo-controlled Phase 1b trial evaluating the safety, tolerability and pharmacokinetics of multiple ascending intravenous doses of PMN310 in patients with mild cognitive impairment due to Alzheimer's disease or mild Alzheimer's disease. The study has completed enrollment of 144 participants across three dosing cohorts, with patients receiving treatment for 12 months. Unblinded topline results, including efficacy data, are expected in the first quarter of 2027.

PMN310 received Fast Track Designation from the US Food and Drug Administration (FDA) in July 2025. The therapy follows encouraging results from an earlier Phase 1a study conducted in healthy volunteers and is being developed as a potential treatment for Alzheimer's disease with an improved safety profile.