Exhibit 99.1 Etripamil for patients with atrial fibrillation with rapid ventricular rate (AFib-RVR) Milestone Pharmaceuticals Reports First Quarter 2025 Financial Results and Provides Regulatory and Corporate Update Resolution of CRL Manufacturing issues in progress - Type A meeting requested No clinical safety or ef icacy concerns raised by FDA MONTREAL and CHARLOTTE, N.C., May 14, 2025 (GLOBE NEWSWIRE) -- Milestone Pharmaceuticals Inc. (Nasdaq: MIST) today reported financial results for the first quarter ...

Core Viewpoint - Milestone Pharmaceuticals is actively addressing the Chemistry, Manufacturing, and Controls (CMC) issues raised by the FDA regarding its lead product CARDAMYST for the treatment of paroxysmal supraventricular tachycardia (PSVT) and is preparing for a Type A meeting with the FDA to resolve these issues [1][2][6]. Financial Results - As of March 31, 2025, the company reported cash, cash equivalents, and short-term investments totaling $56.0 million, a decrease from $69.7 million as of December 31, 2024 [11]. - The company reported no revenue for the first quarter of 2025, consistent with the same period in 2024 [11]. - Research and development expenses increased to $5.0 million in Q1 2025 from $3.6 million in Q1 2024, primarily due to higher consulting costs [11]. - General and administrative expenses rose to $5.2 million in Q1 2025 from $4.0 million in the prior year, driven by increased outside service costs [11]. - Commercial expenses surged to $10.4 million in Q1 2025 from $2.9 million in Q1 2024, reflecting preparations for the launch of CARDAMYST [11]. - The net loss for the first quarter of 2025 was $20.8 million, compared to a net loss of $10.4 million in the same period last year [11]. Product Development and Regulatory Updates - The FDA issued a Complete Response Letter (CRL) for CARDAMYST in March 2025, citing two key CMC issues: the need for additional information on nitrosamine impurities and a new facility inspection to ensure compliance with Good Manufacturing Practices (GMP) [6]. - The Phase 3 study protocol for etripamil in patients with atrial fibrillation with rapid ventricular rate (AFib-RVR) has been finalized, but enrollment is paused to focus on resolving the CRL for PSVT [4]. - A new method of use patent for etripamil nasal spray was issued, potentially extending intellectual property protection until July 2042 [6]. - CARDAMYST was recognized in an independent survey as a new drug expected to significantly impact patient health, with 40% of respondents selecting it [6]. Company Overview - Milestone Pharmaceuticals is focused on developing innovative cardiovascular solutions, with etripamil as its lead investigational product designed for self-administration in treating symptomatic episodes of PSVT and AFib-RVR [9][8].

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, DC 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2025 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-38899 Milestone Pharmaceuticals Inc. (Exact Name of Registrant as Specified in its Charter) (State or other jur ...

Key Takeaways Shares of MIST plunged 66.2% since the CRL issuance, reflecting the delay in the launch of Cardamyst. The company's shares have lost 67.8% so far this year against the industry's 2.2% growth. Despite this regulatory roadblock, analysts remain cautiously optimistic about the drug's prospects. Milestone Pharmaceuticals (MIST) recently announced that the FDA has issued a Complete Response Letter (“CRL”) for its New Drug Application (“NDA”) seeking approval for CARDAMYST (etripamil) nasal spray. ...

Core Viewpoint - Milestone Pharmaceuticals received a Complete Response Letter (CRL) from the FDA regarding its New Drug Application (NDA) for CARDAMYST™ (etripamil) nasal spray, which is intended for the treatment of acute episodes of PSVT in adults, with no clinical safety or efficacy issues raised by the FDA [1][2] Company Overview - Milestone Pharmaceuticals Inc. is a biopharmaceutical company focused on developing innovative cardiovascular solutions to improve the lives of patients with complex heart conditions [4] - The company's lead investigational product, etripamil, is a novel calcium channel blocker nasal spray designed for self-administration to treat symptomatic episodes associated with PSVT and AFib-RVR [3][4] Financial Position - As of December 31, 2024, Milestone Pharmaceuticals had $69.7 million in cash, cash equivalents, and short-term investments [1][2] Regulatory Feedback - The FDA's CRL highlighted two key Chemistry, Manufacturing and Controls (CMC) issues that need to be addressed, but did not raise concerns regarding the clinical safety or efficacy of etripamil [2][6] - The company plans to request a Type A meeting with the FDA to discuss the issues raised in the CRL and is committed to addressing these concerns for a potential resubmission [2][6] Product Development - Etripamil is designed as a self-administered rapid response therapy, allowing patients to manage their condition without immediate medical oversight [3] - The product has undergone a robust clinical trial program, including a completed Phase 3 clinical-stage program for PSVT and a Phase 2 trial for AFib-RVR [3]

Group 1 - The focus is on small and microcap biopharmaceutical companies where mispricing is most intense and institutional attention is minimal [1] - These companies are often in clinical stages and experience significant market movements due to retail ownership and analyst coverage from investment banks with vested interests [1] - The research team consists mainly of high-ranking Life Sciences students from top UK universities, aiming to improve the accuracy of clinical stage equity research [1] Group 2 - Excidium Research maintains a long position in Milestone Pharmaceuticals, indicating a potential bias in their analysis [2] - The report emphasizes the importance of conducting independent due diligence and considering multiple perspectives before making investment decisions [2] - Investing in biotechnology and pharmaceutical companies carries significant risks, including clinical trial failures and regulatory challenges [2]

Core Insights - Milestone Pharmaceuticals Inc. is set to present findings on etripamil's effectiveness in treating Paroxysmal Supraventricular Tachycardia (PSVT) at the American College of Cardiology annual meeting [1][2] - The data suggests that etripamil can convert multiple PSVT episodes to restore normal sinus rhythm, potentially enhancing patient quality of life [2][3] Company Overview - Milestone Pharmaceuticals focuses on developing innovative cardiovascular solutions aimed at improving the lives of patients with complex heart conditions [3] - The company's lead product, etripamil, is a novel calcium channel blocker nasal spray designed for self-administration by patients experiencing symptomatic episodic attacks associated with PSVT and AFib-RVR [3] Presentation Details - The moderated poster presentation titled "Consistency and Predictiveness of Conversion Among Multiple Episodes of Paroxysmal Supraventricular Tachycardia (PSVT) Treated with Etripamil: Outcomes from the NODE-303 trial" will be presented by Dr. James Ip [2] - The presentation is scheduled for March 30, 2025, from 11:42 to 11:49 AM Central Time at the ACC25 event in Chicago [2]

Financial Performance - Milestone Pharmaceuticals reported a net loss of $41.5 million or $0.67 per share for the full year ended December 31, 2024, compared to a net loss of $59.7 million or $1.39 per share for the prior year[6]. - The company recorded no revenue for the fourth quarter or full year 2024, compared to $1.0 million in 2023, which was related to a milestone payment from Corxel Pharmaceuticals[5]. - General and administrative expenses for the full year 2024 were $16.7 million, compared to $15.9 million in 2023, driven by increased outside service costs[5]. - Commercial expenses for the full year 2024 were $11.0 million, down from $15.1 million in the prior year, reflecting cost reductions following the resolution of a Refusal to File letter from the FDA[5]. Cash and Investments - As of December 31, 2024, Milestone had cash, cash equivalents, and short-term investments totaling $69.7 million, an increase from $66.0 million on December 31, 2023[5]. - Total assets as of December 31, 2024, were $75.5 million, slightly up from $75.2 million on December 31, 2023[12]. Research and Development - Research and development expenses decreased to $14.4 million for the full year 2024, down from $31.1 million in 2023, primarily due to lower clinical expenses following the completion of phase 3 studies[5]. - Milestone is preparing for the potential FDA approval of CARDAMYST™ (etripamil) nasal spray for Paroxysmal Supraventricular Tachycardia (PSVT), with a PDUFA review goal date set for March 27, 2025[1]. - A new Method of Use patent for etripamil nasal spray has been allowed, potentially extending intellectual property protection until July 2042[2]. - The company plans to initiate a Phase 3 trial for etripamil in AFib-RVR in 2025, with the protocol finalized and study start-up commenced[4].

Core Insights - Milestone Pharmaceuticals is awaiting FDA approval for CARDAMYST™ (etripamil) nasal spray for the treatment of Paroxysmal Supraventricular Tachycardia (PSVT), with a PDUFA review goal date set for March 27, 2025, and a proposed launch targeted for mid-2025 [1][5] - The company is well-capitalized to commercialize CARDAMYST upon approval, having secured resources for its launch preparations [2][5] - Milestone is also on track to initiate a Phase 3 trial for etripamil in patients with AFib-RVR in 2025, with the study protocol finalized [3] Financial Performance - As of December 31, 2024, Milestone reported cash, cash equivalents, and short-term investments totaling $69.7 million, an increase from $66.0 million at the end of 2023 [4] - The company recorded no revenue for the fourth quarter or full year ended December 31, 2024, compared to $1.0 million in 2023, which was related to a milestone payment [10] - Research and development expenses for Q4 2024 were $3.9 million, down from $5.5 million in the prior year, while full-year expenses were $14.4 million compared to $31.1 million in 2023 [10] - The net loss for Q4 2024 was $12.4 million or $0.19 per share, compared to a net loss of $13.6 million or $0.32 per share for the same period in 2023 [10] Regulatory and Intellectual Property Updates - The New Drug Application (NDA) for CARDAMYST is currently under review by the FDA, with acceptance received in May 2024 [5] - A Notice of Allowance was received from the U.S. Patent and Trademark Office for a new Method of Use patent for etripamil nasal spray, potentially extending intellectual property protection until July 2042 [5] Product Overview - Etripamil is a novel calcium channel blocker nasal spray designed for self-administration to treat symptomatic episodes of PSVT and AFib-RVR, allowing patients to manage their condition without immediate medical oversight [7][8] - The product has undergone a robust clinical trial program, including a completed Phase 3 study for PSVT and a Phase 2 trial for AFib-RVR [7]

Financial Performance - The company incurred a net loss of $41.5 million for the year ended December 31, 2024, compared to a net loss of $59.7 million for 2023, resulting in an accumulated deficit of $367.5 million as of December 31, 2024[162]. - The company expects its existing cash and cash equivalents will be sufficient to fund operations for at least the next 12 months, but substantial additional funding will be required for ongoing operations and planned activities[172]. - Economic uncertainty, including inflation and geopolitical tensions, may adversely affect the company's results of operations and access to capital[178]. - The company may need to raise additional capital through equity or debt financing, which could dilute shareholder ownership and restrict operational flexibility[179]. Product Development and Regulatory Approval - Etripamil is the only product candidate currently under development, with no regulatory approval obtained yet[184]. - The FDA accepted the NDA for etripamil in May 2024 after a resubmission following a Refusal to File letter in December 2023[189]. - The lengthy and unpredictable approval process may significantly harm the company's business and financial condition if regulatory approvals are not obtained[186]. - The FDA may require additional clinical trials or impose restrictions on marketing approvals, which could adversely affect the company's prospects[207]. - The company plans to conduct Phase 3 development for etripamil in treating AFib-RVR, anticipating patient enrollment in the first half of 2025[192]. - The establishment of sales and marketing capabilities is critical for the successful commercialization of etripamil, but this process is expected to be expensive and time-consuming[224]. Clinical Trials and Safety Concerns - The NODE-301 trial of etripamil for PSVT did not meet its primary endpoint, highlighting the uncertainty in achieving commercial success for etripamil and future product candidates[174]. - Clinical trials are expensive and time-consuming, with the possibility of delays impacting the commercialization timeline of product candidates[206]. - Three serious adverse events were reported in the Phase 2 clinical trial, which were considered possibly related to etripamil, highlighting potential safety concerns[214]. - In the Phase 2 clinical trial of etripamil for PSVT, only 104 out of 199 enrolled patients completed the trials, with 70 patients unable to induce or sustain episodes of SVT during the trial period[211]. Market and Competitive Landscape - The company anticipates that sales of etripamil will generate substantially all of its revenues for the foreseeable future, making market acceptance vital for business sustainability[229]. - The company faces substantial competition from major pharmaceutical and biotechnology companies, which may hinder its ability to develop and commercialize drugs successfully[232]. - Coverage and adequate reimbursement for etripamil and future candidates may not be available, impacting market acceptance and sales[243]. - The market opportunities for etripamil and future product candidates may be smaller than estimated, potentially adversely affecting the business[231]. Intellectual Property and Patent Risks - The patent protection for etripamil is critical, and any failure to maintain or obtain sufficient patent rights could allow competitors to develop similar products[302]. - The company may need to defend its patents against challenges, which could result in loss of exclusivity or patent claims being invalidated, limiting its ability to prevent competitors from using similar technologies[309]. - Changes in patent laws may affect the scope and enforceability of the company's patent rights, creating uncertainty in the commercial value of its intellectual property[304]. - The company may face claims asserting that its employees have wrongfully used or disclosed trade secrets, which could result in litigation and substantial costs[324]. Regulatory Compliance and Legal Risks - Compliance with federal and state healthcare laws is critical, as non-compliance could lead to substantial penalties and affect business operations[263]. - The company must navigate complex healthcare regulations that vary by state and country, complicating compliance efforts[271]. - The company is dependent on third-party manufacturers for the production of clinical supplies, which must comply with FDA regulations[283]. - Ongoing regulatory oversight will apply to etripamil and future candidates even after obtaining approval, which may impose additional costs and requirements[255]. Cybersecurity and Data Privacy - Cybersecurity threats pose a significant risk to the company's operations, potentially leading to material disruptions and adverse consequences[346]. - The company has implemented security measures to protect its information technology systems, but future breaches could harm its competitive position and delay product development[349]. - The company is subject to various data privacy laws, including the EU GDPR, UK GDPR, and China's PIPL, which impose strict requirements for processing personal data[357]. - Compliance with evolving data privacy laws may increase operational costs and legal risks for the company and its third-party partners[356].