Exhibit 99.1

ProMIS Neurosciences Announces First Quarter 2026 Financial Results and Provides Corporate Highlights
| ● | Company closed PIPE financing with gross proceeds of up to $175 million, including the possible exercise of warrants, from long-term global investors. Proceeds are expected to fund the Company through 2027, including completion of the ongoing Phase 1b clinical trial in Alzheimer's disease (AD). |
| ● | PRECISE-AD Phase 1b trial is fully enrolled and progressing on schedule, with the blinded 6-month interim analysis anticipated in early Q3 2026 and 12-month top-line data anticipated in early 2027. |
| ● | The planned interim analysis is expected to include a qualitative assessment of aggregated safety data, including amyloid-related imaging abnormalities (ARIA) incidence, as well as key biomarker trends across all study participants at the 6-month timepoint. |
Cambridge, Massachusetts, May 12, 2026 (GLOBE NEWSWIRE) -- ProMIS Neurosciences Inc. (Nasdaq: PMN), a clinical-stage biotechnology company focused on the generation and development of antibody therapeutics targeting toxic misfolded proteins in neurodegenerative diseases, today announced its financial results for the quarter ended March 31, 2026, and provided a corporate update.
"2026 has the potential to be a significant year for patients with Alzheimer's disease and their caregivers,” said Neil Warma, Chief Executive Officer of ProMIS Neurosciences. “We believe ProMIS is well-positioned with PMN310 as a potentially differentiated treatment for patients with early AD. We are coming off a productive quarter, having closed a transformational financing of up to $175 million, including potential proceeds from warrant exercises, and have executed well on our Phase 1b clinical trial. Near-term data catalysts, including the blinded 6-month interim analysis, are anticipated in early Q3 2026, and could provide important insight into the potential of our lead drug candidate, PMN310.
With currently marketed AD therapies, safety remains a central concern. Both approved plaque-directed antibodies carry black box warnings for a serious side effect known as ARIA, which encompasses cerebral edema (ARIA-E) and microhemorrhages (ARIA-H) in the brain. ARIA is believed to be associated with therapies that bind amyloid plaque. Given the modest clinical benefit observed with these therapies, ARIA-related risk has been a meaningful consideration in real-world treatment decisions for many patients and physicians.
A growing body of evidence supports the view that toxic soluble amyloid-beta oligomers, small soluble species that form upstream of plaque, are a primary driver of cognitive decline in AD. PMN310 has been designed to selectively target these toxic oligomers while sparing plaque, a mechanism we believe may enable improved efficacy and a differentiated safety profile relative to plaque-directed antibodies.
ProMIS’s Phase 1b trial, PRECISE-AD, was fully enrolled in December 2025, exceeding the company’s target, and we are now approaching the 6-month timepoint of the trial. The upcoming blinded interim data analysis anticipated in early Q3 2026 will summarize aggregate safety data and overall trends in key biomarkers across all study participants, without revealing treatment assignments. Because the analysis pools active and placebo groups under the blind, even modest directional changes could provide early indications of target engagement while preserving the integrity of the trial.
ProMIS expects to complete 12-month dosing for all patients by year-end and to report unblinded top-line results in early 2027, providing a comprehensive view of PMN310's safety, biomarker, and clinical outcomes by treatment group, and an important clinical test of PMN310’s selective targeting approach."
Corporate Highlights
Alzheimer’s Disease (AD) Program (PMN310)
| ● | The Company is conducting the PRECISE-AD Phase 1b clinical trial, which is fully enrolled with 144 participants across three dosing cohorts receiving treatment over a 12-month period. |
| ● | A blinded interim analysis is anticipated in early third quarter 2026, providing a mid-study review of aggregated safety data and overall biomarker trends across all participants. As this analysis remains blinded, individual treatment assignments will not |