ProMIS Neurosciences, Inc.

Results indicated PMN310 was generally well-tolerated and monthly dosing can provide CSF levels adequate for target engagement Initiation of Phase 1b clinical trial in Alzheimer’s disease patients planned for year-end 2024 CAMBRIDGE, Massachusetts and TORONTO, Ontario, Oct. 30, 2024 (GLOBE NEWSWIRE) -- ProMIS Neurosciences Inc. (Nasdaq: PMN), a biotechnology company focused on the generation and development of antibody therapeutics targeting toxic misfolded proteins in neurodegenerative diseases such as Alzheimer’s disease (AD), amyotrophic lateral sclerosis (ALS) and multiple system atrophy (MSA), today presented positive results from all five cohorts from the Phase 1a, single ascending dose clinical trial of its lead product candidate, PMN310, at the 17th Clinical Trials on Alzheimer’s Disease (CTAD) Conference taking place from October 29 – November 1, 2024 in Madrid, Spain. PMN310 is an investigational humanized monoclonal antibody (mAb) designed and developed to selectively target soluble amyloid beta oligomers (AβOs), which ProMIS believes to be the most toxic and pathogenic form of Aβ, relative to Aβ monomers and amyloid plaques. The Phase 1a clinical trial was a randomized, double-blind, placebo-controlled study evaluating the safety, tolerability and pharmacokinetics of PMN310 in 40 healthy volunteers in the United States (NCT06105528). PMN310 was generally well-tolerated in all five single-ascending dose cohorts (2.5, 5, 10, 20 and 40 mg/kg) of the Phase 1a clinical trial and, importantly, crossed the blood brain barrier in healthy volunteers in a dose dependent manner with pharmacokinetics suggesting that monthly dosing may provide levels of PMN310 adequate for target engagement in AD patients. The complete dataset from all five cohorts reinforces previously reported data from the first four cohorts of the Phase 1a trial announced in July 2024 found here. “We are pleased to present additional results from our first-in-human Phase 1a clinical trial of PMN310 that demonstrated PMN310 was generally well tolerated and achieved concentrations in the cerebrospinal fluid indicating its potential for target engagement in AD patients,” said Larry Altstiel, M.D., Ph.D., Chief Medical Officer of ProMIS Neurosciences. “Importantly, these results have confirmed the dosing levels for our planned 12-month, multiple ascending dose Phase 1b clinical trial in 100 patients with mild cognitive impairment due to AD and early AD, which we plan to initiate by year-end 2024. This is a significant milestone for ProMIS, and we were pleased to share our progress at this at this year’s CTAD Conference.” Details of the poster presentation are as follows: Title: Phase 1a Single Ascending Dose Study of PMN310, a monoclonal antibody directed against toxic Aβ oligomers Date/Time of Presentation: Wednesday, October 30 at 3:00pm – 5:00 CET Authors: Larry Altstiel, Johanne Kaplan, Ebrima Gibbs, Misty Lamendola, Wendy Luca, Gavin Malenfant, Mark Maginn, Yanyan Han, Neil Cashman The abstract presentation is available on the Posters and Publications page of the Company’s website at www.promisneurosciences.com. PMN310 builds on a large body of scientific evidence that points to the role of soluble amyloid-beta oligomers (AO) as a primary driver of Alzheimer’s disease pathology. By selectively targeting toxic oligomers, ProMIS seeks to expand therapeutic options beyond those treatments that target amyloid plaques, which it believes could provide a differentiated treatment for AD patients. Initiation of the PMN310 Phase 1b study is planned for the fourth quarter of 2024. About the Phase 1a Clinical Trial The Phase 1a clinical trial was a randomized, double-blind, placebo-controlled study in 40 healthy volunteers in the United States (NCT06105528). The study consisted of five single ascending dose (SAD) cohorts and was designed to evaluate the safety, tolerability, and pharmacokinetics (PK) of intravenous doses of PMN310. The five dosing cohorts were 2.5, 5, 10, 20 and 40 mg/kg. The decision to escalate dosing was made by a data safety monitoring board based on analysis of safety data. Serum PMN310 concentrations were collected before, and at the end of the infusion and at 0.5, 1, 2, 4, 8, 12, 24, 36, 72, 192 hours and approximately biweekly after infusion. CSF collection was done at day 3 and day 29 after dosing to determine CSF concentration of PMN310. For more information on the Phase 1a, Double-Blind, Placebo-Controlled, Single Ascending Dose Study of the Safety, Tolerability and Pharmacokinetics of PMN310 Infusions in Healthy Volunteers study (NCT06105528), please visit www.clinicaltrials.gov. About PMN310 ‎PMN310 is a humanized monoclonal antibody (mAb) designed and developed based on its selectivity for soluble amyloid beta oligomers (AβOs), which ProMIS believes are the most toxic and pathogenic form of Aβ, relative to Aβ monomers and amyloid plaque. Soluble AβOs have been observed to be potent neurotoxins that bind to neurons, inhibit synaptic function and induce neurodegeneration. By selectively targeting toxic soluble AβOs, PMN310 aims to directly address the growing body of evidence suggesting that they represent a primary underlying cause of the neurodegenerative process in Alzheimer’s disease. About ProMIS Neurosciences Inc. ProMIS Neurosciences Inc. is a clinical stage biotechnology company focused on generating and developing antibody therapeutics selectively targeting toxic misfolded proteins in neurodegenerative diseases such as Alzheimer’s disease (AD), amyotrophic lateral sclerosis (ALS) and multiple system atrophy (MSA). The Company’s proprietary target discovery engine applies a thermodynamic, computational discovery platform - ProMIS™ and Collective Coordinates - to predict novel targets known as Disease Specific Epitopes on the molecular surface of misfolded proteins. Using this unique approach, the Company is developing novel antibody therapeutics for AD, ALS and MSA. ProMIS has offices in Cambridge, Massachusetts and Toronto, Ontario. Forward-Looking Statements This press release contains forward-looking statements that are made pursuant to the safe harbor provisions of the Private Securities Litigation Reform Act of 1995. Certain information in this news release constitutes forward-looking statements and forward-looking information (collectively, ‎‎“forward-looking information”) within the meaning of applicable securities laws. In some cases, but not necessarily in all cases, forward-looking information can be identified by the ‎use of forward-looking terminology such as “plans”, “excited to”, “targets”, “expects” or “does not expect”, “is expected”, “an opportunity exists”, ‎‎“is positioned”, “estimates”, “intends”, “assumes”, “anticipates” or “does not anticipate” or “believes”, or variations of such words and ‎phrases or state that certain actions, events or results “may”, “could”, “would”, “might”, “will” or “will be taken”, “occur” or “be ‎achieved”. In addition, any statements that refer to expectations, projections or other characterizations of future events or ‎circumstances contain forward-looking information. Specifically, this news release contains forward-looking information relating to the Company’s results from its Phase 1a study and the potential implications thereof, the Company's expectations regarding its clinical development of its lead product candidate, PMN310, for AD, the Company’s plans to advance into a Phase 1b multiple ascending dose study in AD patients in the fourth quarter of 2024, statements relating to the potential for such studies to provide the first proof-of-concept data for PMN310, and the potential that PMN310 has the potential to positively benefit patients with AD, the targeting of toxic misfolded proteins in neurodegenerative diseases that the Company believes may directly address fundamental AD pathology (including the belief and understanding that toxic oligomers of Aβ are a major driver of AD) and have greater therapeutic potential due to reduction of off-target activity. Statements containing forward-looking information are not historical facts but instead represent management's current ‎expectations, estimates and projections regarding the future of our business, future plans, strategies, projections, anticipated events ‎and trends, the economy and other future conditions. Forward-looking information is necessarily based on a number of opinions, assumptions and estimates that, while considered reasonable by the Company as of the date of this news release, are subject to ‎known and unknown risks, uncertainties and assumptions and other factors that may cause the actual results, level of activity, ‎performance or achievements to be materially different from those expressed or implied by such forward-looking information, including, but not limited to, the risk that the results of nonclinical studies and early clinical trials are not necessarily predictive of future results with PMN310, the Company’s ability to fund its operations and continue as a going concern, its accumulated deficit and the expectation for continued losses and future financial results. Important factors that could cause actual results to differ materially from those indicated in the forward-looking information include, among others, the factors discussed throughout the “Risk Factors” section of the Company's most recently filed Annual Report on Form 10-K for the year ended December 31, 2023 and in its subsequent filings filed with the United States Securities and Exchange Commission. Except as required by applicable securities laws, the Company undertakes no obligation to publicly update any forward-looking information, whether written or oral, that may be made from time to time, whether as a result of new information, future developments or otherwise. For further information: Visit us at www.promisneurosciences.com Please submit media inquiries to info@promisneurosciences.com. For Investor Relations, please contact: Precision AQ (formerly Stern IR)Anne Marie Fields, Managing Directorannemarie.fields@precisionaq.comTel. 212-362-1200

CAMBRIDGE, Massachusetts and TORONTO, Ontario, Sept. 12, 2024 (GLOBE NEWSWIRE) -- ProMIS Neurosciences Inc. (Nasdaq: PMN), a biotechnology company focused on the generation and development of antibody therapeutics targeting toxic misfolded proteins in neurodegenerative diseases such as Alzheimer’s disease (AD), amyotrophic lateral sclerosis (ALS) and multiple system atrophy (MSA), today announced that preclinical data supporting the potential role of its lead product candidate, PMN310, as a treatment for AD will be highlighted in an oral presentation at the 4th International Conference on Cognitive & Behavioral Neurosciences (ICBN) taking place from September 12-13, 2024 in Lisbon, Portugal. A large body of evidence indicates that the most pathogenic species of amyloid-beta (Aß) in AD consists of soluble toxic oligomers as opposed to insoluble fibrils and monomers. The ability of a therapeutic antibody to target toxic amyloid-beta oligomers (AßO) without being diverted by binding to competing non-toxic species has the potential to result in greater efficacy. As a next generation antibody, PMN310 is a therapeutic candidate designed to target toxic oligomers more selectively. “The data being shared at ICBN further support PMN310 as a potential treatment for AD due to its enhanced selectivity for toxic oligomers” stated Johanne Kaplan, Ph.D., Chief Development Officer of ProMIS Neurosciences and platform presenter. “Importantly, the ability of PMN310 to avoid interaction with plaque and vascular deposits of amyloid-beta could potentially reduce the risk of amyloid-related imaging abnormalities, or ARIA, a dose-limiting toxicity associated with plaque-binding antibodies.” In the studies, the binding of PMN310 and other Aß-directed antibodies to a toxic oligomer-enriched low molecular fraction of brain extract from AD patients was evaluated by surface plasmon resonance, with and without monomer competition. The results indicated that PMN310 showed little or no interaction with monomers and was among the least impacted by excess monomer competition in binding to toxic oligomers in AD brain extract. Additionally, PMN310 did not bind to Aß plaque or vascular deposits as determined by immunohistochemistry. These results highlight how PMN310 distinguishes itself from other Aß-directed antibodies and may potentially provide an improved product profile with enhanced efficacy. Details of the oral presentation are as follows: Title: Distinguishing between amyloid-beta directed antibodies: Ability of PMN310 to target toxic oligomers despite competing species Date/Time of Virtual Presentation: Friday, September 13 at 2:00pm WEST (6:00am PT / 9:00am ET)Authors: Johanne Kaplan, Ebrima Gibbs, Juliane Coutts, Beibei Zhao, Neil R. Cashman The slide presentation is available on the Posters and Publications page of the Company’s website at www.promisneurosciences.com. In July 2024, ProMIS Neurosciences reported positive topline data from the first four cohorts in its first-in-human Phase 1a clinical trial of PMN310, demonstrating that it met objectives for tolerability, safety and pharmacokinetics. The Company expects to report topline results from all five cohorts [in the coming months] and is on-track to advance PMN310 into a Phase 1b study in the fourth quarter of 2024. About PMN310PMN310 is a humanized monoclonal antibody (mAb) designed and developed based on its selectivity for soluble amyloid beta oligomers (AβOs), which ProMIS believes are the most toxic and pathogenic form of Aβ, relative to Aβ monomers and amyloid plaque. Soluble AβOs have been observed to be potent neurotoxins that bind to neurons, inhibit synaptic function and induce neurodegeneration. By selectively targeting toxic soluble AβOs, PMN310 aims to directly address the growing body of evidence suggesting that they represent a primary underlying cause of the neurodegenerative process in Alzheimer’s disease. About ProMIS Neurosciences Inc. ProMIS Neurosciences Inc. is a clinical stage biotechnology company focused on generating and developing antibody therapeutics selectively targeting toxic misfolded proteins in neurodegenerative diseases such as Alzheimer’s disease (AD), amyotrophic lateral sclerosis (ALS) and multiple system atrophy (MSA). The Company’s proprietary target discovery engine applies a thermodynamic, computational discovery platform - ProMIS™ and Collective Coordinates - to predict novel targets known as Disease Specific Epitopes on the molecular surface of misfolded proteins. Using this unique approach, the Company is developing novel antibody therapeutics for AD, ALS and MSA. ProMIS has offices in Toronto, Ontario and Cambridge, Massachusetts. Forward-Looking Statements This press release contains forward-looking statements that are made pursuant to the safe harbor provisions of the Private Securities Litigation Reform Act of 1995. Certain information in this news release constitutes forward-looking statements and forward-looking information (collectively, ‎‎“forward-looking information”) within the meaning of applicable securities laws. In some cases, but not necessarily in all cases, forward-looking information can be identified by the ‎use of forward-looking terminology such as “plans”, “excited to”, “targets”, “expects” or “does not expect”, “is expected”, “an opportunity exists”, ‎‎“is positioned”, “estimates”, “intends”, “assumes”, “anticipates” or “does not anticipate” or “believes”, or variations of such words and ‎phrases or state that certain actions, events or results “may”, “could”, “would”, “might”, “will” or “will be taken”, “occur” or “be ‎achieved”. In addition, any statements that refer to expectations, projections or other characterizations of future events or ‎circumstances contain forward-looking information. Specifically, this news release contains forward-looking information relating to the Company’s preclinical data, novel vaccine approach to target toxic oligomers and the potential implications thereof, the Company's expectations regarding its clinical development of its lead product, PMN310, for AD, and the Company’s plans to announce additional results and advance into a Phase 1b multiple ascending dose study in AD patients. Statements containing forward-looking information are not historical facts but instead represent management's current ‎expectations, estimates and projections regarding the future of our business, future plans, strategies, projections, anticipated events ‎and trends, the economy and other future conditions. Forward-looking information is necessarily based on a number of opinions, assumptions and estimates that, while considered reasonable by the Company as of the date of this news release, are subject to ‎known and unknown risks, uncertainties and assumptions and other factors that may cause the actual results, level of activity, ‎performance or achievements to be materially different from those expressed or implied by such forward-looking information, including, but not limited to, the risk that the results of nonclinical studies and early clinical trials are not necessarily predictive of future results with PMN310, the Company’s ability to fund its operations and continue as a going concern, its accumulated deficit and the expectation for continued losses and future financial results. Important factors that could cause actual results to differ materially from those indicated in the forward-looking information include, among others, the factors discussed throughout the “Risk Factors” section of the Company's most recently filed Annual Report on Form 10-K for the year ended December 31, 2023 and in its subsequent filings filed with the United States Securities and Exchange Commission. Except as required by applicable securities laws, the Company undertakes no obligation to publicly update any forward-looking information, whether written or oral, that may be made from time to time, whether as a result of new information, future developments or otherwise. For further information: Visit us at www.promisneurosciences.com Please submit media inquiries to info@promisneurosciences.com. For Investor Relations, please contact: Precision AQ (formerly Stern IR)Anne Marie Fields, Managing Directorannemarie.fields@precisionaq.comTel. 212-362-1200

Reported positive topline data from first-in-human Phase 1a clinical trial of PMN310 as a treatment for Alzheimer’s disease that met objectives for tolerability, safety and pharmacokinetics Secured up to $122.7 million in private placement financing from leading healthcare specialty funds to advance Phase 1b study of PMN310 in Alzheimer’s disease patients in second half 2024 CAMBRIDGE, Massachusetts and TORONTO, Ontario, Aug. 08, 2024 (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 such as Alzheimer’s disease (AD), amyotrophic lateral sclerosis (ALS) and multiple system atrophy (MSA), today announced financial results for the second quarter ended June 30, 2024 and provided a corporate update. “We are coming off a very important and successful few months for ProMIS as we reported positive top-line Phase 1a data and closed on a strong financing, which could bring in up to $122.7 million to support our Alzheimer’s candidate and pipeline compounds,” said Neil Warma, CEO of ProMIS Neurosciences. “We believe these events have transformed ProMIS and now place us at the forefront of companies developing therapies for dementia, as we advance one of the most promising candidates in the clinic for Alzheimer’s disease. Top-line data from the first four of five cohorts in the Phase 1a clinical trial showed PMN310 to be generally safe and well-tolerated and, importantly, showed that PMN310 crossed into the central nervous system in quantities suggesting we may see potential target engagement in the upcoming Phase 1b clinical study.” “Given that PMN310 is designed to bind only to toxic oligomeric forms of amyloid beta and to avoid any binding to amyloid beta plaque, we do not expect to see elevated levels of swelling or bleeding of the brain known as ARIA, a serious side effect that has been associated with almost all of the plaque-binding drugs on the market and in development. The apparent selectivity of PMN310 could potentially differentiate it significantly in its efficacy and safety profile as it continues through clinical development in an upcoming Phase 1b trial. This randomized, placebo controlled, double blind clinical trial is expected to enroll 100 patients and will not only evaluate critical biomarkers and incidence of ARIA but will also extend for 12 months to enable us to measure important clinical endpoints. The trial design is particularly robust and comprehensive for a Phase 1b study, in order to validate PMN310’s significant differentiation on efficacy and safety. We are excited to be moving quickly to initiate this clinical study in the coming months,” added Mr. Warma. Recent Highlights Alzheimer’s Disease Program (PMN310) ProMIS’ lead candidate, PMN310, is a humanized IgG1 antibody directed toward toxic amyloid-beta (Ab) oligomers (AβO) that are believed to be a major driver of Alzheimer’s disease (AD). The Phase 1a clinical trial was a randomized, double-blind, placebo-controlled trial evaluating the safety and tolerability of PMN310 in healthy normal volunteers (NCT06105528). The trial consisted of five single-ascending dose (SAD) cohorts and was designed to evaluate the safety, tolerability, and pharmacokinetics (PK), of intravenous doses of PMN310. The trial completed enrollment of all 40 subjects across 2 active sites in the United States. The trial was initiated based on encouraging nonclinical studies of PMN310 that support the selective targeting of AβOs.In July 2024, ProMIS reported positive data from the first four cohorts in its first-in-human Phase 1a clinical trial of PMN310 in healthy volunteers. PMN310 was well-tolerated through the first four SAD dose cohorts (2.5, 5, 10, 20 mg/kg), with no treatment-emergent serious adverse events (SAEs) observed after administration of PMN310. Cerebrospinal fluid (CSF) was collected on days 3 and 29 after PMN310 administration. Tests showed that the levels of PMN310 in the CSF increased proportionally with the dosage on both days 3 and 29. Even at the lowest dose, PMN310 appeared to be present at over 100 times the concentration of the oligomers in the CNS. The half-life of PMN310 in CSF was approximately 25 days, which is supportive of once per month dosing.The Company expects to report topline results from all five cohorts in the second half of 2024 and to present the full dataset at an upcoming medical meeting. ProMIS continues to advance its amyloid beta vaccine program in AD based on its oligomer target epitope(s). In July 2024, the Company presented preclinical data in a poster at the Alzheimer’s Association International Conference (AAIC), which took place from July 29-August 1, 2024 in Philadelphia. The poster titled, “Novel approach to optimization of Alzheimer’s vaccine configuration for maximal targeting of toxic amyloid-beta oligomers,” highlighted data demonstrating that maximal reactivity was observed with immune IgG against the monovalent vaccine containing epitope 301, the target of PMN310, the Company’s clinical-stage monoclonal antibody. Amyotrophic Lateral Sclerosis Disease Program (PMN267) PMN267 is a humanized IgG1 antibody directed against toxic misfolded TDP-43 as a potential therapeutic target for ALS. In August 2024, ProMIS announced the publication of two papers highlighting the role of toxic misfolded superoxide dismutase-1 (SOD1) aggregates in the pathogenesis of ALS. One paper published in Acta Neuropathologica is titled, “Seeding activity of human superoxide dismutase 1 aggregates in familial and sporadic amyotrophic lateral sclerosis postmortem neural tissues by real-time quaking-induced conversion,” and the other publication in the online journal, Open Biology, is titled, “Amyloidogenic regions in beta-strands II and III modulate the aggregation and toxicity of SOD1 in living cells.” The Acta Neuropathologica publication can be accessed here, and the Open Biology publication can be accessed here. In April 2024, the Company announced the publication of supportive preclinical data for PMN267 as a potential therapeutic agent for ALS in the Journal of Biological Chemistry in an article titled, “Tryptophan residues in TDP-43 and SOD1 modulate the cross-seeding and toxicity of SOD1." The publication can be accessed here. Corporate In July 2024, ProMIS completed a private investment in public equity (PIPE) financing that will provide up to $122.7 million in gross proceeds, which includes an initial upfront funding of $30.3 million and up to $92.4 million tied to exercise of warrants based on the Company achieving certain milestones, with certain of the warrants being subject to shareholder approval. The PIPE financing included participation from new and existing healthcare specialist investors such as Great Point Partners, LLC, Armistice Capital, Ally Bridge Group, Sphera Healthcare, and other institutional and individual accredited investors. Proceeds from the private placement are expected to be used to advance the clinical development of PMN310, as well as for working capital and other general corporate expenses. Second Quarter 2024 Financial Highlights Cash and cash equivalents were $1.0 million as of June 30, 2024, compared to $12.6 million as of December 31, 2023. Following the close of the quarter, in July 2024, the Company completed a PIPE financing that provided initial upfront funding of $30.3 million and which has the potential to provide an addition $92.4 million tied to exercise of warrants based on the Company achieving certain milestones, with certain of the warrants being subject to shareholder approval. Research and development expenses were $1.6 million for the three-months ended June 30, 2024, compared to $1.0 million for the same period in 2023, primarily attributable to a $0.9 million increase in direct research and development expenses related to PMN310 Phase 1a clinical trial costs, offset by a decrease of $0.2 million in consulting expenses. General and administrative expenses decreased to $1.1 million for the quarter ended June 30, 2024, compared to $1.9 million for the same period in 2023, which included one-time costs of $0.8 million related to expensing previously deferred financing costs. Net loss was $2.6 million for the quarter ended June 30, 2024, compared to a net loss of $2.3 million for the same period in 2023. About ProMIS Neurosciences Inc. ProMIS Neurosciences Inc. is a clinical stage biotechnology company focused on generating and developing antibody therapeutics selectively targeting toxic misfolded proteins in neurodegenerative diseases such as Alzheimer’s disease (AD), amyotrophic lateral sclerosis (ALS) and multiple system atrophy (MSA). The Company’s proprietary target discovery engine applies a thermodynamic, computational discovery platform - ProMIS™ and Collective Coordinates - to predict novel targets known as Disease Specific Epitopes on the molecular surface of misfolded proteins. Using this unique approach, the Company is developing novel antibody therapeutics for AD, ALS and MSA. ProMIS has offices in Cambridge, Massachusetts and Toronto, Ontario. Forward-Looking Statements Nasdaq has not reviewed and does not accept responsibility for the adequacy or accuracy of this release. Certain information in this news release constitutes forward-looking statements and forward-looking information (collectively, ‎‎“forward-looking information”) within the meaning of applicable securities laws. In some cases, but not necessarily in all cases, forward-looking information can be identified by the ‎use of forward-looking terminology such as “plans”, “targets”, “expects” or “does not expect”, “is expected”, “excited about”, “an opportunity exists”, ‎‎“is positioned”, “estimates”, “intends”, “assumes”, “anticipates” or “does not anticipate” or “believes”, or variations of such words and ‎phrases or state that certain actions, events or results “may”, “could”, “would”, “might”, “will” or “will be taken”, “occur” or “be ‎achieved”. In addition, any statements that refer to expectations, projections or other characterizations of future events or ‎circumstances contain forward-looking information. Specifically, this news release contains forward-looking information relating to the announcement of results of all five cohorts of the Company’s Phase 1a study, plans to advance PMN310 into a Phase 1b MAD study in AD patients and expectations of such study results, the potential for such studies to provide the first proof-of-concept data for PMN310, the potential that PMN310 has the potential to positively benefit patients with AD, the targeting of toxic misfolded proteins in neurodegenerative diseases that the Company believes may directly address fundamental AD pathology (including the belief and understanding that toxic oligomers of Aβ are a major driver of AD) and have greater therapeutic potential due to reduction of off-target activity, a computationally-derived Aβ vaccine for AD and the Company’s PMN310 antibody and vaccine candidate, management’s belief that its patented platform technology has created an antibody candidate specific to toxic misfolded oligomers known to be present in AD, therapeutic activity and preferential targeting of toxic soluble aggregates by Aß-directed antibodies and the potential implications thereof, the Company’s pipeline, including application of its platform to other diseases, statements regarding preclinical data, including data announced regarding ALS, the ability to continue its growth and realize the anticipated contribution of the members of its board of directors and executives to its operation and progress, use of capital expenses, including the use of proceeds from the PIPE financing, future accumulated deficit and other financial results in the future, ability to fund operations, the ability to maintain enough liquidity to execute its business plan and its ability to continue as a going concern. Statements containing forward-looking information are not historical facts but instead represent management's current ‎expectations, estimates and projections regarding the future of our business, future plans, strategies, projections, anticipated events ‎and trends, the economy and other future conditions. Forward-looking information is necessarily based on a number of opinions, assumptions and estimates that, while considered reasonable by the Company as of the date of this news release, are subject to ‎known and unknown risks, uncertainties and assumptions and other factors that may cause the actual results, level of activity, ‎performance or achievements to be materially different from those expressed or implied by such forward-looking information, including, but not limited to, the risk that preclinical results or early results may not be indicative of future results, the Company’s ability to fund its operations and continue as a going concern, its accumulated deficit and the expectation for continued losses and future financial results. Important factors that could cause actual results to differ materially from those indicated in the forward-looking information include, among others, the factors discussed throughout the “Risk Factors” section of the Company's most recently filed Annual Report on Form 10-K for the year ended December 31, 2023 and in its subsequent filings filed with the United States Securities and Exchange Commission. Except as required by applicable securities laws, the Company undertakes no obligation to publicly update any forward-looking information, whether written or oral, that may be made from time to time, whether as a result of new information, future developments or otherwise. For further information: Visit us at www.promisneurosciences.com Please submit media inquiries to info@promisneurosciences.com For Investor Relations, please contact: Precision AQAnne Marie Fields, Managing Directorannemarie.fields@precisionaq.comTel. 212-362-1200 PROMIS NEUROSCIENCES INC. Condensed Consolidated Balance Sheets (expressed in US dollars, except share amounts)(Unaudited) June 30, December 31, 2024 2023 Assets Current assets: Cash $992,463 $12,598,146 Short-term investments 32,358 32,358 Prepaid expenses and other current assets 384,776 988,641 Total current assets 1,409,597 13,619,145 Total assets $1,409,597 $13,619,145 Liabilities and Shareholders' (Deficit) Equity Current liabilities: Accounts payable $2,015,167 $7,843,136 Accrued liabilities 1,156,789 1,506,526 Total current liabilities 3,171,956 9,349,662 Share-based compensation liability 465,488 422,002 Warrant liability 49,231 94,185 Total liabilities 3,686,675 9,865,849 Commitments and contingencies Shareholders' (deficit) equity: Series 2 Convertible Preferred Shares, no par value, unlimited shares authorized, 1,166,667 shares issued and outstanding as of June 30, 2024 and December 31, 2023 — — Common shares, no par value, unlimited shares authorized, 18,961,116 and 18,885,254 shares issued and outstanding as of June 30, 2024 and December 31, 2023, respectively — — Additional paid-in capital 97,818,797 97,590,426 Accumulated other comprehensive loss (371,184) (371,184) Accumulated deficit (99,724,691) (93,465,946) Total shareholders' (deficit) equity (2,277,078) 3,753,296 Total liabilities and shareholders' (deficit) equity $1,409,597 $13,619,145 PROMIS NEUROSCIENCES INC. Condensed Consolidated Statements of Operations and Comprehensive Loss (expressed in US dollars, except share amounts)(Unaudited) For the For the For the For the Three Months Ended Three Months Ended Six Months Ended Six Months Ended June 30, June 30, June 30, June 30, 2024 2023 2024 2023 Operating expenses: Research and development $1,625,821 $1,005,715 $3,749,599 $4,515,967 General and administrative 1,087,885 1,894,169 2,640,758 3,354,588 Total operating expenses 2,713,706 2,899,884 6,390,357 7,870,555 Loss from operations (2,713,706) (2,899,884) (6,390,357) (7,870,555) Other income (expense): Change in fair value of financial instruments 59,087 606,214 44,954 564,549 Interest expense — (49,182) (76,774) (49,182) Other income 30,962 30,878 163,432 83,783 Total other income (expense), net 90,049 587,910 131,612 599,150 Net loss (2,623,657) (2,311,974) (6,258,745) (7,271,405) Other comprehensive loss Foreign currency translation adjustment — (171,462) — (175,816) Comprehensive loss $(2,623,657) $(2,483,436) $(6,258,745) $(7,447,221) Net loss per share, basic and diluted $(0.13) $(0.27) $(0.32) $(0.85) Weighted-average shares outstanding of common shares, basic and diluted 19,770,739 8,579,284 19,544,908 8,579,284