ProMIS Neurosciences to Host Webinar to Discuss Upcoming 6-Month Blinded Interim Data from PRECISE-AD Phase 1b Trial of PMN310 in Alzheimer’s Disease

ProMIS Neurosciences Inc. (Nasdaq: PMN), a clinical-stage biotechnology company developing antibody therapeutics and vaccines targeting toxic misfolded proteins in neurodegenerative diseases, today announced that it will host a webinar on Tuesday, July 28, 2026, at 8:00 am ET, featuring Key Opinion Leaders (KOLs) Dr. Will Mantyh, Associate Professor with Tenure, University of Minnesota Medical School and Dr. Michael Weiner, Professor Emeritus, University of California, San Francisco. They will join company leadership to discuss the Company's six-month blinded interim data from the PRECISE-AD Phase 1b trial evaluating PMN310 in patients with early Alzheimer's disease (AD). The analysis will focus on blinded aggregate safety data and overall trends in select biomarkers across study participants.

Webinar Details Date: July 28, 2026 Time: 8:00-9:00 am ET Speakers (ProMIS): Neil Warma, Chief Executive Officer, and Dr. Larry Altstiel, Chief Medical Officer KOLs: Dr. Will Mantyh and Dr. Michael Weiner Registration link: https://lifescievents.com/event/it38tlq/ About Dr. Will Mantyh William G. Mantyh, M.D. is an Associate Professor with Tenure in Behavioral/Cognitive Neurology at the University of Minnesota, specializing in Alzheimer's disease and related neurodegenerative disorders. His research focuses on blood-based biomarkers, APOE genetics, and expanding equitable access to Alzheimer's diagnosis and treatment in underserved communities. He is the principal investigator of a $3.7 million NIH grant studying Alzheimer's blood tests in Native American communities and serves as M Health Fairview's Practice Leader for new biomarker and anti-amyloid infusion care models. Dr. Mantyh earned his M.D. from the University of Minnesota, completed his internship and neurology residency at Mayo Clinic, and finished a fellowship in Behavioral Neurology at the University of California, San Francisco.

About Dr. Michael Weiner Dr. Weiner is UCSF Professor Emeritus of Radiology and Biomedical Imaging, Medicine, Psychiatry, and Neurology, and the CEO of the AI voice company, Vaicro. He has conducted research for over 60 years and is Principal Investigator of the Alzheimer's Disease Neuroimaging Initiative (ADNI) and the BrainHealthRegistry.org. He was one of the first to perform nuclear magnetic resonance on an intact animal. He then pursued development of MRI/MRS as a clinical tool and established the Center for Imaging of Neurodegenerative Diseases at the San Francisco VAMC. Dr. Weiner has published over 1,030 peer-reviewed articles, trained dozens of postdoctoral fellows, and received numerous honors including the Alzheimer’s Association’s Nancy and Ronald Reagan Award, the Potamkin Prize of the American Academy of Neurology, a Docteur Honoris Causa Degree from Paul Sabatier University, Toulouse, France, and the Henry Wisniewski Lifetime Achievement Award in Alzheimer's Disease Research, from the Alzheimer's Association in 2021. His current interest is AI applications to ADRD research, especially development of AI-powered conversational voice agents to perform clinical and cognitive assessments.

About PMN310 and the PRECISE-AD Trial for Alzheimer’s Disease (AD) PMN310, ProMIS’ lead product candidate for the treatment of AD, is a humanized IgG1 monoclonal antibody designed to selectively target only the toxic oligomers of amyloid-beta (AβOs), believed to be among the earliest and most damaging drivers of Alzheimer's disease, while avoiding binding to amyloid plaques and vascular deposits. This selectivity may reduce or eliminate the risk of amyloid-related imaging abnormalities (ARIA), including brain swelling (ARIA-E) and microhemorrhages (ARIA-H), which are commonly associated with plaque-binding antibodies. PMN310 was granted Fast Track Designation by the U.S. Food and Drug Administration in July 2025.

Based on encouraging results from a Phase 1a trial (NCT06105528) in healthy volunteers, ProMIS initiated the PRECISE-AD Phase 1b trial to evaluate PMN310 in patients with mild cognitive impairment due to AD or mild AD. PRECISE-AD (NCT06750432) is a randomized, double-blind, placebo-controlled study evaluating the safety, tolerability, and pharmacokinetics of multiple ascending doses (5, 10, and 20 mg/kg) of intravenous PMN310. The study has completed enrollment of 144 participants across the three dosing cohorts who are being treated for twelve months. It is designed to provide meaningful insight into the effects of PMN310 on biomarkers and clinical outcomes.

About ProMIS Neurosciences Inc. ProMIS Neurosciences is a clinical-stage biotechnology company committed to the discovery and development of therapeutic antibodies and vaccines selective for toxic oligomers associated with the development and progression of neurodegenerative and other misfolded protein diseases. The Company’s proprietary target discovery engine, EpiSelect™, has been shown to predict novel targets known as Disease Specific Epitopes (DSEs) on the molecular surface of misfolded proteins that cause neurodegenerative diseases, including Alzheimer’s disease (AD), amyotrophic lateral sclerosis (ALS), frontotemporal dementia (FTD), multiple system atrophy (MSA), and Parkinson’s disease (PD). ProMIS has offices in Cambridge, Massachusetts (USA).

For further information: Visit us at www.promisneurosciences.com Media Contact Maggie Whitney LifeSci Communications [email protected]

Investor Relations Contact Carie Pierce VP Investor Relations & External Affairs [email protected]