ProMIS Neurosciences: PRECISE-AD Phase 1b trial proceeds to final dose escalation cohort.

• Cohort 2 fully enrolled in PRECISE-AD Phase 1b clinical trial • No cases of amyloid-related imaging abnormalities (ARIA) observed • Cohort 3 (final dose level) dosing underway • 128-patient trial expected to report 6-month data in Q2 2026 and 12-month data in Q4 2026.

ProMIS Neurosciences, Inc. (Nasdaq: PMN) has reported significant progress in its PRECISE-AD Phase 1b clinical trial, a study evaluating the safety, tolerability, and pharmacokinetics of multiple ascending doses of its lead product candidate, PMN310, for the treatment of Alzheimer's disease (AD). The trial, which aims to enroll 128 patients, is designed to assess the effects of a monoclonal antibody directed solely against amyloid-beta oligomers (AβOs) on biomarkers associated with AD pathology and clinical outcomes.

The independent Data and Safety Monitoring Board (DSMB) for the PRECISE-AD trial has unanimously recommended that the company proceed to the third and final dose escalation cohort. This decision follows a review of available safety data through Cohort 2, which has now been fully enrolled, with no cases of amyloid-related imaging abnormalities (ARIA) observed to date. Enrollment of patients into Cohort 3 is now underway, with the trial expected to deliver 6-month interim data in the second quarter of 2026 and final 12-month top-line results in the fourth quarter of 2026 [1].

Neil Warma, President and CEO of ProMIS Neurosciences, commented on the DSMB's recommendation, stating, "The DSMB’s recommendation to proceed with the planned escalation to the final dose cohort underscores the steady progress of our Phase 1b program and keeps us firmly on track toward our planned interim and top-line data readouts in 2026." Warma also highlighted the potential of PMN310 to meet a critical unmet need in AD by targeting toxic oligomers, which are believed to be a major driver of the disease, rather than amyloid plaque [1].

Larry Altstiel, M.D., Ph.D., Chief Medical Officer of ProMIS Neurosciences, noted the favorable safety profile observed with PMN310 to date. He emphasized the potential of the drug to reduce off-target effects and focus therapeutic activity on the molecular species most implicated in disease progression. Altstiel also mentioned the comprehensive biomarker panel that will be assessed in the final cohort, including pTau217, pTau243, neurofilament light chain (NfL), glial fibrillary acidic protein (GFAP), Abeta42/40 ratios, and synaptic integrity markers such as SNAP25 and neurogranin [1].

PMN310 is a humanized IgG1 antibody designed to selectively target only toxic oligomers, avoiding plaque, thereby potentially reducing or eliminating ARIA liability. This differentiated strategy sets PMN310 apart from other amyloid-directed antibody therapeutics, which have been associated with safety concerns. The DSMB's clearance to continue the trial and proceed to the next and final dosing level, going from the 10 mg/kg dose of PMN310 in the second cohort to the 20mg/kg dose for the final cohort, underscores the positive safety profile observed to date [1].

ProMIS Neurosciences' President and CEO, Neil Warma, will discuss the company's clinical progress along with other corporate updates at the upcoming H.C. Wainwright 27th Annual Global Investment Conference on September 10, 2025. The webcast of the presentation will be available for at least 30 days following the event [1].

Reference List:
[1] https://www.promisneurosciences.com/investors/news-events/press-releases/detail/252/promis-neurosciences-receives-dsmb-approval-to-advance-to