FDA Accepted the Company’s Response to the CRL for CARDAMYST™ (etripamil) Nasal Spray; New PDUFA Target Date of December 13, 2025 Milestone Strengthens Balance Sheet to Fully Commercialize CARDAMYST if Approved Public Offering Raised Total Gross Proceeds of up to $170 Million if all Warrants are Exercised $75 Million Royalty Purchase Agreement Payment from RTW Extended Through End of 2025 MONTREAL and CHARLOTTE, N.C., Aug. 12, 2025 (GLOBE NEWSWIRE) — Milestone Pharmaceuticals Inc. (Nasdaq: MIST) today reported financial results for the second quarter ended June 30, 2025 and provided corporate and regulatory updates. “With the FDA’s recent acceptance of our response to the CRL, our team is energized as we work toward the potential approval of CARDAMYST in its first indication, PSVT,” said Joe Oliveto, President and Chief Executive Officer of Milestone. “In parallel to our regulatory progress, we completed an equity financing in July with high-quality investors which strengthened our balance sheet and extended our operating runway. Our goal is to make CARDAMYST quickly available to PSVT patients, should the FDA grant approval this year.” Second Quarter and Recent Program Updates Etripamil for patients with PSVT FDA accepted the Company’s response to the Complete Response Letter (CRL) for CARDAMYST™ (etripamil) Nasal Spray and set a new Prescription Drug User Fee Act (PDFUA) target date of December 13, 2025.  In June, Milestone submitted to the FDA its response to a CRL for CARDAMYST, its lead investigational product for the management of paroxysmal supraventricular tachycardia (PSVT). On July 11, 2025, the Company announced the FDA accepted the response to issues raised in the CRL and assigned a new PDUFA target date of December 13, 2025. Milestone has maintained its launch infrastructure that was in place prior to the CRL and has restarted targeted pre-launch activities given the new potential approval date of CARDAMYST. Etripamil for patients with atrial fibrillation with rapid ventricular rate (AFib-RVR) Phase 3 protocol of etripamil in AFib-RVR finalized. Milestone has finalized the Phase 3 study protocol following FDA’s review and obtained concurrence with the Agency to proceed. The Company has paused initiation of enrollment in the study to prioritize resources for the preparation of the expected launch of etripamil in PSVT. Second Quarter and Recent Corporate Updates In July 2025, Milestone completed a public equity offering, raising total gross proceeds of up to $170 million, if all Series A and B warrants are exercised for cash, including immediate net proceeds of approximately $48.7 million. Milestone intends to use the proceeds from the underwritten public offering (the “Offering”), together with existing cash and cash equivalents, to fund the continued development and commercial launch of CARDAMYST in its lead indication of PSVT, as well as for working capital and other general corporate purposes. The Offering consisted of the sale and issuance of (i) 31,500,000 of its common shares (the “Shares”), accompanying Series A common warrants (the “Series A Common Warrants”) to purchase an aggregate of 31,500,000 common shares and accompanying Series B common warrants (the “Series B Common Warrants”) to purchase an aggregate of 31,500,000 common shares , at a combined public offering price of $1.50 per share and accompanying Series A Common Warrant and Series B Common Warrant and (ii) in lieu of common shares to certain investors that so choose, pre-funded warrants to purchase 3,502,335 common shares, accompanying Series A Common Warrants to purchase an aggregate of 3,502,335 common shares and accompanying Series B Common Warrants to purchase an aggregate of 3,502,335 common shares, at a combined public offering price of $1.499 per pre-funded warrant and accompanying Series A Common Warrant and Series B Common Warrant, which represented the combined public offering price for the Shares and accompanying common warrants less the $0.001 per share exercise price for each such pre-funded warrant. The net proceeds to the Company received from the Offering were approximately $48.7 million after deducting underwriting commissions and estimated offering expenses payable by the Company.Amended Royalty Agreement with RTW. Milestone extended the marketing approval deadline in its $75 million purchase and sale agreement (the “Royalty Purchase Agreement”) with existing shareholder, RTW Investments, LP, and certain of its affiliates (RTW) from September 30, 2025 to December 31, 2025. The proceeds from the Royalty Purchase Agreement are expected to fund the continued development and commercial launch of CARDAMYST in its lead indication of PSVT, following potential FDA approval and satisfaction of other customary closing conditions. Second Quarter 2025 Financial Results   As of June 30, 2025, Milestone had cash, cash equivalents, and short-term investments of $43.4 million, compared to $69.7 million as of December 31, 2024. Subsequent to the end of the quarter, the company raised net proceeds of approximately $48.7 million from the Offering, as described above.There was no revenue for the second quarter ended June 30, 2025 or for the second quarter of 2024.Research and development expense for the second quarter of 2025 was $3.7 million, compared with $2.8 million for the prior year period. For the six months ended June 30, 2025, research and development expense was $8.6 million compared with $6.5 million for the same period in 2024. The increase was primarily due to higher consulting and outside service costs that were partially offset by lower personnel-related costs.General and administrative expense for the second quarter of 2025 was $3.8 million, compared with $5.0 million for the prior year period. For the six months ended June 30, 2025, general and administrative expense was $8.9 million, compared with the $9.0 million for the prior year period.  The decrease between the quarters is primarily due to a decrease in legal fees, professional fees, and personnel costs.Commercial expense for the second quarter of 2025 was $5.1 million, compared with $1.8 million for the prior year period. For the six months ended June 30, 2025, commercial expense was $15.5 million compared with $4.7 million for the prior year period. These increases are a result of additional personnel costs, professional costs and other operational expenses related to preparation for the launch of CARDAMYST. As a result of the CRL, Milestone temporarily paused the ramping of operational expenditures related to launch, but has maintained the capability to launch quickly, pending approval of CARDAMYST by the FDA.For the second quarter of 2025, net loss was $13.0 million, compared to $9.4 million for the prior year period. For the six months ended June 30, 2025, Milestone’s net loss was $33.7 million, compared to $19.7 million in the prior year period. For further details on the Company’s financials, refer to the Quarterly Report on Form 10-Q for the quarter ended June 30, 2025, filed with the SEC. About EtripamilEtripamil is Milestone’s lead investigational product. It is a novel calcium channel blocker nasal spray under clinical development for frequent and often highly symptomatic episodes of PSVT and AFib-RVR. It is designed as a self-administered rapid response therapy for patients thereby bypassing the need for immediate medical oversight. If approved, etripamil is intended to provide health care providers with a new treatment option to enable on-demand care and patient self-management. This portable, self-administered treatment may provide patients with active management and a greater sense of control over their condition. CARDAMYST™, the conditionally approved brand name for etripamil nasal spray, is well studied with a robust clinical trial program that includes a completed Phase 3 clinical-stage program for the treatment of PSVT and Phase 2 trial for the treatment of patients with AFib-RVR. About Milestone PharmaceuticalsMilestone Pharmaceuticals Inc. (Nasdaq: MIST) is a biopharmaceutical company developing and commercializing innovative cardiovascular solutions to improve the lives of people living with complex and life-altering heart conditions. The Company’s focus on understanding unmet patient needs and improving the patient experience has led us to develop new treatment approaches that provide patients with an active role in self-managing their care. Milestone’s lead investigational product is etripamil, a novel calcium channel blocker nasal spray that is being studied for patients to self-administer without medical supervision to treat symptomatic episodic attacks associated with PSVT and AFib-RVR. Forward-Looking Statements This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Words such as “believe,” “continue,” “could,” “demonstrate,” “designed,” “develop,” “estimate,” “expect,” “may,” “pending,” “plan,” “potential,” “progress,” “will”, “intend” and similar expressions (as well as other words or expressions referencing future events, conditions, or circumstances) are intended to identify forward-looking statements. These forward-looking statements are based on Milestone’s expectations and assumptions as of the date of this press release. Each of these forward-looking statements involves risks and uncertainties. Actual results may differ materially from these forward-looking statements. Forward-looking statements contained in this press release include statements regarding: the outcomes of future interactions with the FDA, including the potential approval of the NDA for CARDAMYST for PSVT; Milestone’s ability to receive additional cash proceeds from the warrants issued in the Offering; Milestone’s ability to receive the $75.0 million royalty payment under the Royalty Purchase Agreement on the timeline provided, or at all; Milestone’s expected operating runway; CARDAMYST’s potential as a novel treatment option to help patients with PSVT; Milestone’s ability to make CARDAMYST quickly available to PSVT patients following FDA approval, if received; the success of Milestone’s launch infrastructure; the timing of patient enrollment in the Phase 3 study of etripamil for AFib-RVR; and other statements not related to historical facts. Important factors that could cause actual results to differ materially from those in the forward-looking statements include, but are not limited to, whether our future interactions with the FDA will have satisfactory outcomes; whether and when, if at all, our NDA for etripamil will be approved by the FDA; uncertainties related to the timing of initiation, enrollment, completion, evaluation and results of our clinical trials; risks and uncertainty related to the complexity inherent in cleaning, verifying and analyzing trial data; and whether the clinical trials will validate the safety and efficacy of etripamil for PSVT or other indications, among others, general economic, political, and market conditions, including deteriorating market conditions due to investor concerns regarding inflation, international tariffs, Russian hostilities in Ukraine and ongoing disputes in Israel and Gaza and overall fluctuations in the financial markets in the United States and abroad, risks related to pandemics and public health emergencies, and risks related the sufficiency of Milestone’s capital resources and its ability to raise additional capital in the current economic climate. These and other risks are set forth in Milestone’s filings with the U.S. Securities and Exchange Commission (SEC), including in its annual report on Form 10-K for the year ended December 31, 2025 and its quarterly report on Form 10-Q for the quarter ended June 30, 2025, in each case under the caption “Risk Factors,” as such discussions may be updated from time to time by subsequent filings Milestone may make with the SEC. Except as required by law, Milestone assumes no obligation to update any forward-looking statements contained herein to reflect any change in expectations, even as new information becomes available. Contact:  Investor Relations Kevin Gardner, kgardner@lifesciadvisors.com        Milestone Pharmaceuticals Inc.Condensed Consolidated Balance Sheets (Unaudited)(in thousands of US dollars, except share data)       June 30, 2025 December 31, 2024Assets           Current assets     Cash and cash equivalents$42,499  $25,314 Short-term investments918  44,381 Research and development tax credits receivable1,079  901 Prepaid expenses748  1,840 Other receivables924  1,490 Total current assets46,168  73,926 Operating lease right-of-use assets1,090  1,376 Property and equipment159  197 Total assets$47,417  $75,499       Liabilities, and Shareholders’ (Deficit) Equity           Current liabilities     Accounts payable and accrued liabilities$8,768  $7,555 Operating lease liabilities515  571 Total current liabilities9,283  8,126 Operating lease liabilities, net of current portion641  874 Senior secured convertible notes55,238  53,352 Total liabilities65,162  62,352             Shareholders’ (Deficit) Equity     Common shares, no par value, unlimited shares authorized, 53,494,261 shares issued and outstanding as of June 30, 2025, 53,353,984 shares issued and outstanding as of December 31, 2024288,263  288,048 Pre-funded warrants – 12,910,590 issued and outstanding as of June 30, 2025 and 12,910,590 as of December 31, 202453,076  53,076 Additional paid-in capital42,188  39,568 Accumulated deficit(401,272) (367,545)      Total shareholders’ (deficit) equity(17,745) 13,147       Total liabilities and shareholders’ equity$47,417  $75,499       Milestone Pharmaceuticals Inc.Condensed Consolidated Statements of Loss (Unaudited)(in thousands of US dollars, except share and per share data)                 Three months ended June 30, Six months ended June 30, 2025 2024 2025 2024                Revenue$—  $—  $—  $—                 Operating expenses               Research and development, net of tax credits 3,669   2,815   8,647   6,454 General and administrative 3,759   5,046   8,926   8,999 Commercial 5,103   1,801   15,481   4,685                 Loss from operations (12,531)  (9,662)  (33,054)  (20,138)                Interest income 516   1,186   1,213   2,180 Interest expense (951)  (887)  (1,886)  (1,759)                Net loss and comprehensive loss$(12,966) $(9,363) $(33,727) $(19,717)                Weighted average number of shares and pre-funded warrants outstanding, basic and diluted  66,380,118   66,165,461   66,333,024   58,160,286                 Net loss per share, basic and diluted$(0.20) $(0.14) $(0.51) $(0.34)                

MONTREAL and CHARLOTTE, N.C., July 11, 2025 (GLOBE NEWSWIRE) — Milestone® Pharmaceuticals Inc. (“Milestone”) (Nasdaq: MIST), a biopharmaceutical company focused on the development and commercialization of innovative cardiovascular medicines, today announced the pricing of its previously announced underwritten public offering (the “Offering”) of (i) 31,500,000 of its common shares (the “Shares”), accompanying Series A common warrants (the “Series A Common Warrants”) to purchase an aggregate of 31,500,000 common shares and accompanying Series B common warrants (the “Series B Common Warrants”) to purchase an aggregate of 31,500,000 common shares , at a combined public offering price of $1.50 per share and accompanying Series A Common Warrant and Series B Common Warrant and (ii) in lieu of common shares to certain investors that so choose, pre-funded warrants to purchase 3,502,335 common shares, accompanying Series A Common Warrants to purchase an aggregate of 3,502,335 common shares and accompanying Series B Common Warrants to purchase an aggregate of 3,502,335 common shares, at a combined public offering price of $1.499 per pre-funded warrant and accompanying Series A Common Warrant and Series B Common Warrant, which represents the combined public offering price for the Shares and accompanying common warrants less the $0.001 per share exercise price for each such pre-funded warrant. The proceeds to Milestone from the Offering, before deducting underwriting commissions and offering expenses payable by Milestone, are expected to be approximately $52.5 million. The Offering is expected to close on or about July 14, 2025, subject to satisfaction of customary closing conditions. Milestone intends to use the net proceeds from the Offering together with existing cash and cash equivalents, to fund the clinical development and commercial launch of etripamil in its lead indication of paroxysmal supraventricular tachycardia (PSVT), as well as for working capital and other general corporate purposes. TD Cowen, Piper Sandler & Co. and Wells Fargo Securities are acting as joint book-running managers for the Offering. H.C. Wainwright & Co. is acting as lead manager for the Offering. The securities described above are being offered by Milestone pursuant to a shelf registration statement on Form S-3 (File No. 333-283162), including a base prospectus, that was declared effective by the U.S. Securities and Exchange Commission (the “SEC”) on November 22, 2024. The Offering is being made only by means of a prospectus supplement and accompanying prospectus that form a part of the registration statement. A final prospectus supplement related to the Offering will be filed with the SEC and will be available on the SEC’s website located at www.sec.gov. A copy of the final prospectus supplement and the accompanying prospectus relating to the Offering may also be obtained, when available, from: TD Securities (USA) LLC, 1 Vanderbilt Avenue, New York, NY 10017, by telephone at 855-495-9846, or by email at TD.ECM_Prospectus@tdsecurities.com; Piper Sandler, Attention: Prospectus Department, 800 Nicollet Mall, J12S03, Minneapolis, Minnesota 55402, or by telephone at (800) 747-3924, or by email at prospectus@psc.com; and Wells Fargo Securities, LLC, 90 South 7th Street, 5th Floor, Minneapolis, MN 55402, or by telephone at 800-645-3751 (option #5), or by email at WFScustomerservice@wellsfargo.com. This press release shall not constitute an offer to sell or a solicitation of an offer to buy any of the securities described herein, nor shall there be any sale of these securities in any state or jurisdiction in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such state or jurisdiction. Any offering in Canada of the securities described herein will be made only on a private placement basis to certain accredited investors. About Milestone Pharmaceuticals  Milestone Pharmaceuticals Inc. (Nasdaq: MIST) is a biopharmaceutical company developing and commercializing innovative cardiovascular medicines to benefit people living with certain heart conditions. Milestone recently submitted a New Drug Application (NDA) to the U.S. Food and Drug Administration (FDA) for etripamil for treatment of an abnormal heart rhythm, paroxysmal supraventricular tachycardia or PSVT.  Forward-Looking Statements This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Words such as “believe,” “continue,” “could,” “demonstrate,” “designed,” “develop,” “estimate,” “expect,” “may,” “pending,” “plan,” “potential,” “progress,” “will” and similar expressions (as well as other words or expressions referencing future events, conditions, or circumstances) are intended to identify forward-looking statements. These forward-looking statements are based on Milestone’s expectations and assumptions as of the date of this press release. Each of these forward-looking statements involves risks and uncertainties. Actual results may differ materially from these forward-looking statements. Forward-looking statements contained in this press release include statements regarding the timing and closing of the Offering, and the anticipated use of proceeds from the Offering. Important factors that could cause actual results to differ materially from those in the forward-looking statements include, but are not limited to, market and other financial conditions; satisfaction of customary closing conditions related to the Offering; whether Milestone’s future interactions with the FDA, including with regard of the new drug application for etripamil for PSVT, will have satisfactory outcomes; uncertainties related to the timing of initiation, enrollment, completion, evaluation and results of Milestone’s clinical trials; risks and uncertainty related to the complexity inherent in cleaning, verifying and analyzing trial data; and whether the clinical trials will validate the safety and efficacy of etripamil for PSVT or other indications, among others, general economic, political, and market conditions, including deteriorating market conditions due to investor concerns regarding inflation, Russian hostilities in Ukraine and ongoing disputes in Israel and Gaza and overall fluctuations in the financial markets in the United States and abroad, risks related to pandemics and public health emergencies, and risks related the sufficiency of Milestone’s capital resources and its ability to raise additional capital in the current economic climate. These and other risks are set forth in Milestone’s filings with the U.S. Securities and Exchange Commission, including in the preliminary prospectus related to the Offering, annual report on Form 10-K for the year ended December 31, 2022 and quarterly report on Form 10-K for the quarterly period ended September 30, 2023, under the caption “Risk Factors,” as such discussion may be updated from time to time by subsequent filings, we may make with the U.S. Securities and Exchange Commission. Milestone cautions you not to place undue reliance on any forward-looking statements, which speak only as of the date they are made. Except as required by law, Milestone assumes no obligation to update any forward-looking statements contained herein to reflect any change in expectations, even as new information becomes available. Contact Investor Relations Kevin Gardner, kgardner@lifesciadvisors.com

Resolution of CRL Manufacturing issues in progress – Type A meeting requested No clinical safety or efficacy 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 ended March 31, 2025. The Company also announced the submission of a meeting request to the U.S. Food and Drug Administration (FDA) as the next step in the resolution of CRL issues. “Our immediate priority is to engage with the U.S. FDA in order to address the CMC-related issues raised in the CRL received for CARDAMYST as a treatment for PSVT,” said Joe Oliveto, President and Chief Executive Officer of Milestone Pharmaceuticals. “We are confident we can work with the FDA to fully respond to the CRL and remain committed to the potential of CARDAMYST. If approved, it will be the first and only self-administered therapy for the rapid termination of episodes of PSVT.” First Quarter and Recent Program Updates Etripamil for Patients with PSVT CRL for CARDAMYST™ for PSVT received from FDA.  In March 2025, Milestone received a CRL regarding its NDA for CARDAMYST, its lead investigational product for the management of paroxysmal supraventricular tachycardia (PSVT). In the letter, the Agency highlighted two key Chemistry, Manufacturing and Controls (CMC) issues to be addressed: 1) additional information on nitrosamine impurities was requested, based on new draft guidance that was issued during the review of the NDA , and 2) a new inspection of a facility listed in the NDA is required, to ensure it is in compliance with current Good Manufacturing Practices (GMP).  The facility, which previously performed a portion of the testing required to release etripamil final product, changed ownership during the review of the NDA. Milestone is prepared to discuss the issues raised in the CRL during the Type A meeting with the FDA.Patent Issued by the U.S. Patent and Trademark Office (USPTO) on a new Method of Use patent for etripamil nasal spray. The new patent (U.S. Patent No. 12,257,224) covers the repeat dose regimen that was used in the RAPID Phase 3 study that evaluated etripamil in PSVT and is included in the proposed package insert for CARDAMYST. The issued patent potentially extends the intellectual property protection for CARDAMYST in the United States until July 2042, which would be an additional six years of protection for the company’s intellectual property portfolio.CARDAMYST highlighted in independent Survey of Managed Care professionals. Results from an independent survey conducted by Managed Healthcare Executive and The American Journal of Managed Care were published on May 6, 2025. CARDAMYST was selected by 40% of respondents (which included payers, providers and academics) when asked which new drug is expected to make the biggest difference in patient health.   A copy of the article can be accessed here.Commercial Launch Plan investor event held in February. The event, held on February 25, 2025 in New York City, provided an in-depth overview of the Company’s commercial strategy for CARDAMYST nasal spray, if approved. A replay of the event, as well as a copy of the slides, can be found on the corporate website here.Poster on etripamil presented at American College of Cardiology Annual Meeting (ACC.25). The poster titled, “Consistency and Predictiveness of Conversion Among Multiple Episodes of Paroxysmal Supraventricular Tachycardia (PSVT) treated with Etripamil: Outcomes from the NODE-303 trial,” was presented at the meeting on March 30, 2025 by James Ip, M.D., Professor, Division of Cardiology, Weill Cornell Medicine, New York Presbyterian Hospital. A copy of the poster can be accessed here. Etripamil for patients with atrial fibrillation with rapid ventricular rate (AFib-RVR) Phase 3 protocol in AFib-RVR finalized Milestone has finalized the Phase 3 study protocol following FDA’s review and obtained concurrence with the Agency to proceed. The Company is pausing initiation of enrollment of the study due to prioritizing resources to resolve the CRL received on the NDA for etripamil in PSVT. First Quarter 2025 Financial Results   As of March 31, 2025, Milestone had cash, cash equivalents, and short-term investments of $56.0 million, compared to $69.7 million as of December 31, 2024.There was no revenue for the first quarter ended March 31, 2025 or for the first quarter of 2024.Research and development expense for the first quarter of 2025 was $5.0 million, compared with $3.6 million for the prior year period. The increase was primarily due to higher consulting costs in drug manufacturing and regulatory costs.General and administrative expense for the first quarter of 2025 was $5.2 million, compared with $4.0 million for the prior year period. This increase was driven primarily by an increase in outside service costs, partially offset by a decrease in personnel costs.Commercial expense for the first quarter of 2025 was $10.4 million, compared with $2.9 million for the prior year period. This increase is a result of additional personnel costs, professional costs and other operational expenses related to preparation for the launch of CARDAMYST. As a result of the CRL, Milestone has temporarily paused the ramping of operational expenditures related to launch, but will maintain the capability to launch quickly, pending approval of CARDAMYST by the FDA.For the first quarter of 2025, net loss was $20.8 million, compared to $10.4 million for the prior year period. For further details on the Company’s financials, refer to the Quarterly Report on Form 10-Q for the quarter ended March 31, 2025, filed with the SEC. About EtripamilEtripamil is Milestone’s lead investigational product. It is a novel calcium channel blocker nasal spray under clinical development for frequent and often highly symptomatic episodes of PSVT and AFib-RVR. It is designed as a self-administered rapid response therapy for patients thereby bypassing the need for immediate medical oversight. If approved, etripamil is intended to provide health care providers with a new treatment option to enable on-demand care and patient self-management. This portable, self-administered treatment may provide patients with active management and a greater sense of control over their condition. CARDAMYST™, the conditionally approved brand name for etripamil nasal spray, is well studied with a robust clinical trial program that includes a completed Phase 3 clinical-stage program for the treatment of PSVT and Phase 2 trial for the treatment of patients with AFib-RVR. About Milestone PharmaceuticalsMilestone Pharmaceuticals Inc. (Nasdaq: MIST) is a biopharmaceutical company developing and commercializing innovative cardiovascular solutions to improve the lives of people living with complex and life-altering heart conditions. The Company’s focus on understanding unmet patient needs and improving the patient experience has led us to develop new treatment approaches that provide patients with an active role in self-managing their care. Milestone’s lead investigational product is etripamil, a novel calcium channel blocker nasal spray that is being studied for patients to self-administer without medical supervision to treat symptomatic episodic attacks associated with PSVT and AFib-RVR. Forward-Looking Statements This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Words such as “believe,” “continue,” “could,” “demonstrate,” “designed,” “develop,” “estimate,” “expect,” “may,” “pending,” “plan,” “potential,” “progress,” “will”, “intend” and similar expressions (as well as other words or expressions referencing future events, conditions, or circumstances) are intended to identify forward-looking statements. These forward-looking statements are based on Milestone’s expectations and assumptions as of the date of this press release. Each of these forward-looking statements involves risks and uncertainties. Actual results may differ materially from these forward-looking statements. Forward-looking statements contained in this press release include statements regarding: the outcomes of future interactions with the FDA, including the potential Type A meeting; Milestone’s ability to address the issues raised in the CRL on a timely basis, if at all; the outcome of the potential NDA resubmission; CARDAMYST’s potential as a novel treatment option to help patients with PSVT; potential protections afforded by U.S. patents; CARDAMYST’s ability to make the biggest difference in patient health, as compared to other available treatment options; the timing of patient enrollment in the Phase 3 study of etripamil for AFib-RVR; and other statements not related to historical facts. Important factors that could cause actual results to differ materially from those in the forward-looking statements include, but are not limited to, whether our future interactions with the FDA will have satisfactory outcomes; whether and when, if at all, our NDA for etripamil will be approved by the FDA; uncertainties related to the timing of initiation, enrollment, completion, evaluation and results of our clinical trials; risks and uncertainty related to the complexity inherent in cleaning, verifying and analyzing trial data; and whether the clinical trials will validate the safety and efficacy of etripamil for PSVT or other indications, among others, general economic, political, and market conditions, including deteriorating market conditions due to investor concerns regarding inflation, international tariffs, Russian hostilities in Ukraine and ongoing disputes in Israel and Gaza and overall fluctuations in the financial markets in the United States and abroad, risks related to pandemics and public health emergencies, and risks related the sufficiency of Milestone’s capital resources and its ability to raise additional capital in the current economic climate. These and other risks are set forth in Milestone’s filings with the U.S. Securities and Exchange Commission (SEC), including in its annual report on Form 10-K for the year ended December 31, 2025 and its quarterly report on Form 10-Q for the quarter ended March 31, 2025, in each case under the caption “Risk Factors,” as such discussions may be updated from time to time by subsequent filings Milestone may make with the SEC. Except as required by law, Milestone assumes no obligation to update any forward-looking statements contained herein to reflect any change in expectations, even as new information becomes available. Contact: Kim Fox, Vice President, Communications, kfox@milestonepharma.com Investor Relations Kevin Gardner, kgardner@lifesciadvisors.com   Milestone Pharmaceuticals Inc.Condensed Consolidated Balance Sheets (Unaudited)(in thousands of US dollars, except share data)         March 31, 2025 December 31, 2024Assets             Current assets      Cash and cash equivalents $45,085  $25,314 Short-term investments  10,873   44,381 Research and development tax credits receivable  994   901 Prepaid expenses  2,356   1,840 Other receivables  1,167   1,490 Total current assets  60,475   73,926 Operating lease right-of-use assets  1,234   1,376 Property and equipment  176   197 Total assets $61,885  $75,499        Liabilities, and Shareholders’ (Deficit) Equity             Current liabilities      Accounts payable and accrued liabilities $12,421  $7,555 Operating lease liabilities  542   571 Total current liabilities  12,963   8,126 Operating lease liabilities, net of current portion  758   874 Senior secured convertible notes  54,287   53,352 Total liabilities  68,008   62,352               Shareholders’ (Deficit) Equity      Common shares, no par value, unlimited shares authorized, 53,464,273 shares issued and outstanding as of March 31, 2025, 53,353,984 shares issued and outstanding as of December 31, 2024  288,188   288,048 Pre-funded warrants – 12,910,590 issued and outstanding as of March 31, 2025 and 12,910,590 as of December 31, 2024  53,076   53,076 Additional paid-in capital  40,919   39,568 Accumulated deficit  (388,306)  (367,545)       Total shareholders’ (deficit) equity  (6,123)  13,147        Total liabilities and shareholders’ equity $61,885  $75,499           Milestone Pharmaceuticals Inc.Condensed Consolidated Statements of Loss (Unaudited)(in thousands of US dollars, except share and per share data)     Three months ended March 31,       2025    2024        Revenue $—  $—        Operating expenses      Research and development, net of tax credits  4,978   3,639 General and administrative  5,167   3,953 Commercial  10,378   2,884        Loss from operations  (20,523)  (10,476)       Interest income  697   994 Interest expense  (935)  (872)       Net loss and comprehensive loss $(20,761) $(10,354)       Weighted average number of shares and pre-funded warrants outstanding, basic and diluted   66,285,406   50,155,111        Net loss per share, basic and diluted $(0.31) $(0.21)

MONTREAL and CHARLOTTE, N.C., Sept. 04, 2024 (GLOBE NEWSWIRE) — Milestone® Pharmaceuticals Inc. (Nasdaq: MIST), a biopharmaceutical company focused on the development and commercialization of innovative cardiovascular medicines, today announced the appointment of Joseph Papa to its Board of Directors (“Board”), effective September 3, 2024.

– Two New Independent Directors, Stuart Duty and Andrew Saik, Appointed – Third New Independent Director to Be Appointed to Board in Near Term MONTREAL and CHARLOTTE, N.C., July 15, 2024 (GLOBE NEWSWIRE) — Milestone® Pharmaceuticals Inc. (Nasdaq: MIST) (“Milestone” or the “Company”), a biopharmaceutical company focused on the development and commercialization of innovative cardiovascular medicines, today announced steps to refresh its Board of Directors (“Board”). Stuart Duty and Andrew Saik have been appointed to its Board, effective immediately, and will stand for election at the Company’s 2024 Annual Meeting of Shareholders (the “Annual Meeting”). The Company will appoint a third independent director to its Board in the near term. In conjunction with the announcement, the Company entered into a Cooperation Agreement (the “Agreement”) with Alta Fundamental Advisers LLC (“Alta”), one of the Company’s shareholders. Mr. Duty has over 30 years of experience in investment banking and operations primarily in the biotechnology and specialty pharmaceuticals sectors. Most recently, he served as a Senior Managing Director at Guggenheim Securities, LLC from 2012 to 2023 where he advised senior executives and boards on a range of financing activities and strategic transactions. Mr. Saik has over 25 years of accounting and finance experience, including as Chief Financial Officer of biopharmaceutical companies Arvinas, Inc., Intercept Pharmaceuticals, Vyne Therapeutics Inc., PDS Biotechnology, Inc. and Vertice Pharma, LLC, where he has led numerous capital structure transformations. “We welcome Stuart and Andrew to our Board and look forward to benefitting from their varied perspectives and experiences,” said Robert J. Wills, PhD, Chairman of the Milestone Board of Directors. “We believe Stuart and Andrew will provide important insights to the Board and are great additions as we approach this particularly exciting time for Milestone.” The Company also announced that Debra K. Liebert and Richard C. Pasternak, MD, will not stand for reelection at the Annual Meeting. Dr. Wills added, “We want to thank Debra and Richard for their years of service and significant contributions as members of the Board. Their invaluable insights in the boardroom brought us closer to realizing our mission of providing a new treatment option for patients with paroxysmal supraventricular tachycardia and atrial fibrillation. We wish them all the best for the future.” Pursuant to the Agreement, Alta has agreed to customary standstill, voting and other related provisions. The Agreement will be included as an exhibit to the Company’s current report on Form 8-K, which will be filed with the U.S. Securities and Exchange Commission (the “SEC”). About Stuart Duty Stuart Duty brings over 30 years of experience in investment banking and operations primarily in the biotechnology and specialty pharmaceuticals sectors. Mr. Duty most recently served as a Senior Managing Director at Guggenheim Securities, LLC from 2012 to 2023, where he advised senior executives and boards on a range of financing activities and strategic transactions, including significant in-country and cross-border transactions in the U.S., Japan, China, Canada and many European countries. Prior to joining Guggenheim, he was a Managing Director, Co-Head, Healthcare Investment Banking at Piper Jaffray from 2007 to 2012, returning to the firm after serving in the same role from 1999 to 2002. Mr. Duty served as Chief Operating Officer of Oracle Partners from 2002 to 2007. Earlier in his career, he served as a Managing Director, Healthcare Investment Banking at Montgomery Securities, as Director, Business Development at Curative Technologies and as a healthcare investment banking analyst at Kidder Peabody. Mr. Duty has served on the board of directors of Achieve Life Sciences, Inc. (Nasdaq: ACHV) since March 2023, where he serves as the chair of the audit committee and sits on the nominating and corporate governance committee, and on the board of directors of EyePoint Pharmaceuticals (Nasdaq: EYPT) since November 2023, where he sits on the audit committee. Mr. Duty holds a BA in Biochemistry from Occidental College and an MBA from Harvard Business School. About Andrew Saik Andrew Saik brings over 25 years of accounting and finance experience at biopharmaceutical companies. Mr. Saik is currently Chief Financial Officer at Arvinas, Inc. (Nasdaq: ARVN). Prior to joining Arvinas, Mr. Saik served as Chief Financial Officer at Intercept Pharmaceuticals from 2021 to 2023, where he led a restructuring of the company’s balance sheet that included the sale of its international business and recapitalization of the company’s debt. Mr. Saik served as Chief Financial Officer of Vyne Therapeutics Inc. from 2020 to 2021. He was Chief Financial Officer and served on the board of directors of PDS Biotechnology, Inc. (formerly Edge Therapeutics) from 2017 to 2020. Before joining PDS, he was Chief Financial Officer at Vertice Pharma, LLC, a Warburg Pincus-backed company, from 2015 to 2017. Mr. Saik was Chief Financial Officer of Auxilium Pharmaceuticals, Inc. from 2014 to 2015, where he helped lead the execution of Auxilium’s growth strategy culminating in the sale of the company. Before joining Auxilium, he was Senior Vice President, Finance and Treasurer at Endo Pharmaceuticals from 2013 to 2014. Earlier in his career, Mr. Saik served in senior financial management roles with increasing responsibility at Valeant Pharmaceuticals International from 2001 to 2012, including as Senior Vice President, Finance. He was a Finance Manager at Nexgenix from 1999 to 2001 and began his career at Atlantic Richfield as Finance Consultant from 1996 to 1999. Mr. Saik holds a BA from the University of California, Los Angeles and an MBA from the University of Southern California. About Milestone Pharmaceuticals Milestone Pharmaceuticals Inc. (Nasdaq: MIST) is a biopharmaceutical company developing and commercializing innovative cardiovascular solutions to improve the lives of people living with complex and life-altering heart conditions. The Company’s focus on understanding unmet patient needs and improving the patient experience has led us to develop new treatment approaches that provide patients with an active role in self-managing their care. Milestone’s lead investigational product is etripamil, a novel calcium channel blocker nasal spray that is being studied for patients to self-administer without medical supervision to treat symptomatic episodic attacks associated with PSVT and AFib-RVR. Forward-Looking Statements This press release contains forward-looking statements and forward-looking information within the meaning of the Private Securities Litigation Reform Act of 1995 and applicable Canadian securities laws (“forward-looking statements”). Words such as “believe,” “continue,” “could,” “demonstrate,” “designed,” “develop,” “estimate,” “expect,” “may,” “pending,” “plan,” “potential,” “progress,” “will,” “intend” and similar expressions (as well as other words or expressions referencing future events, conditions, or circumstances) are intended to identify forward-looking statements. These forward-looking statements are based on Milestone’s expectations and assumptions as of the date of this press release. Each of these forward-looking statements involves risks and uncertainties. Actual results may differ materially from these forward-looking statements. Forward-looking statements contained in this press release include statements regarding the timing of upcoming clinical trial milestones and related data; the company’s cash runway; and the company’s plans to maintain a dialogue with its shareholders. Important factors that could cause actual results to differ materially from those in the forward-looking statements include, but are not limited to, whether our future interactions with the FDA will have satisfactory outcomes; whether and when, if at all, our NDA for etripamil will be approved by the FDA; whether the FDA will require additional trials or data which may significantly delay and put at risk our efforts to obtain approval and may not be successful, the risks inherent in biopharmaceutical product development and clinical trials, including the lengthy and uncertain regulatory approval process; uncertainties related to the timing of initiation, enrollment, completion, evaluation and results of our clinical trials; risks and uncertainty related to the complexity inherent in cleaning, verifying and analyzing trial data; and whether the clinical trials will validate the safety and efficacy of etripamil for PSVT or other indications, among others, general economic, political, and market conditions, including deteriorating market conditions due to investor concerns regarding inflation, Russian hostilities in Ukraine and ongoing disputes in Israel and Gaza and overall fluctuations in the financial markets in the United States and abroad, risks related to pandemics and public health emergencies, and risks related the sufficiency of Milestone’s capital resources and its ability to raise additional capital in the current economic climate. These and other risks are set forth in Milestone’s filings with SEC and the Canadian securities regulatory authorities, including in its annual report on Form 10-K for the year ended December 31, 2023, under the caption “Risk Factors,” as such discussion may be updated from time to time by subsequent filings Milestone may make with the SEC and the Canadian securities regulatory authorities, which is available under Milestone’s profile on EDGAR at www.sec.gov and on SEDAR at www.sedarplus.ca. Except as may be expressly required by applicable law, Milestone assumes no obligation to update any forward-looking statements contained herein to reflect any change in expectations, even as new information becomes available or based on future events or otherwise. Participants in the Solicitation This press release is neither a solicitation of a proxy or consent nor a substitute for any proxy statement or other filings that may be made with the SEC and Canadian securities regulatory authorities. Milestone, its directors, certain of its executive officers, and other members of management and employees may be deemed under U.S. securities laws and Canadian securities laws to be participants in the solicitation of proxies with respect to a solicitation by Milestone. Information about Milestone’s executive officers and directors and other participants in the solicitation, including their respective interests, by security holdings or otherwise, is available in the Company’s proxy statement on Schedule 14A for its 2023 annual meeting of shareholders, filed with the SEC on April 28, 2023 (available here). To the extent holdings of Milestone securities reported in the proxy statement have changed, such changes have been or will be reflected on Statements of Change in Ownership on Forms 3, 4 or 5 filed with the SEC and if applicable, on the System for Electronic Disclosure by Insiders (“SEDI”) in accordance with insider reporting requirements of Canadian securities laws. Updated information regarding the identity of potential participants and their direct or indirect interests, by security holdings or otherwise, in Milestone will be set forth in the Company’s definitive proxy statement for the Annual Meeting and other documents to be filed with the SEC and Canadian securities regulatory authorities, when they become available. These documents are or will be available free of charge at the SEC’s website at www.sec.gov and either through the Company’s profile on SEDAR at www.sedarplus.ca or updated filings on SEDI at www.sedi.ca. Contact:Kim Fox, Vice President, Communications kfox@milestonepharma.com 704-803-9295  Investor RelationsChris Calabrese, ccalabrese@lifesciadvisors.comKevin Gardner, kgardner@lifesciadvisors.com