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 September 30, 2023 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 ...

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION FORM 10-Q WASHINGTON, DC 20549 (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2023 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 juri ...

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, 2023 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 ...

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K (Mark One) ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2022 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Commission file number 001-38899 For the transition period from to Milestone Pharmaceuticals Inc. (Exact name of registrant as specified in its charter) | Québec | Not applicab ...

Forward Looking Statement • Chest pressure or pain Need for simple, fast-acting treatment, reduce trips to ED and calls to physicians • Oral Beta Blockers and Calcium Channel Blockers (CCB) to reduce episodes • Catheter ablation The Presentation contains forward-looking statements within the meaning of the safe harbor provisions of the Private Securities Litigation Reform Act of 1995, as amended. Words such as ''aim,'' ''anticipate,'' ''assume,'' ''believe,'' ''contemplate,'' ''continue,'' ''could,'' ''desi ...

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 September 30, 2022 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 ...

PART I. FINANCIAL INFORMATION [Financial Statements (Unaudited)](index=7&type=section&id=Item%201.%20Financial%20Statements%20(Unaudited)) Unaudited H1 2022 financial statements reflect a decrease in total assets to **$91.3 million** and a net loss of **$30.7 million** Condensed Consolidated Balance Sheets As of June 30, 2022, total assets decreased to **$91.3 million**, primarily due to reduced cash and cash equivalents Condensed Consolidated Balance Sheet Highlights (in thousands of US dollars) | Account | June 30, 2022 | December 31, 2021 | | :--- | :--- | :--- | | **Assets** | | | | Cash and cash equivalents | $63,237 | $114,141 | | Total current assets | $90,502 | $118,923 | | **Total assets** | **$91,299** | **$119,849** | | **Liabilities & Equity** | | | | Total current liabilities | $4,256 | $6,775 | | **Total liabilities** | **$4,640** | **$7,249** | | **Total shareholders' equity** | **$86,659** | **$112,600** | Condensed Consolidated Statements of Earnings (Loss) Q2 2022 net loss was **$16.6 million** due to no revenue, and H1 2022 net loss increased to **$30.7 million** Statement of Earnings (Loss) Summary (in thousands of US dollars, except per share data) | Metric | Three Months Ended June 30, 2022 | Three Months Ended June 30, 2021 | Six Months Ended June 30, 2022 | Six Months Ended June 30, 2021 | | :--- | :--- | :--- | :--- | :--- | | Revenue | $0 | $15,000 | $0 | $15,000 | | Research and development | $10,657 | $9,427 | $19,425 | $18,022 | | General and administrative | $3,918 | $3,018 | $7,561 | $5,651 | | Commercial | $2,231 | $1,843 | $3,867 | $3,209 | | **Net earnings (loss)** | **$(16,648)** | **$770** | **$(30,655)** | **$(11,744)** | | **Net earnings (loss) per share, basic** | **$(0.39)** | **$0.02** | **$(0.73)** | **$(0.28)** | Condensed Consolidated Statements of Cash Flows H1 2022 net cash used in operations was **$28.0 million**, resulting in a **$50.9 million** net decrease in cash and cash equivalents Cash Flow Summary (in thousands of US dollars) | Activity | Six Months Ended June 30, 2022 | Six Months Ended June 30, 2021 | | :--- | :--- | :--- | | Net cash used in operating activities | $(28,034) | $(11,455) | | Net cash provided by (used in) investing activities | $(23,059) | $32,000 | | Cash provided by financing activities | $189 | $4,939 | | **Net decrease in cash and cash equivalents** | **$(50,904)** | **$25,484** | | **Cash and cash equivalents – End of period** | **$63,237** | **$97,794** | Notes to Unaudited Condensed Consolidated Financial Statements Notes detail operations, accounting policies, and financial position, including a **$237.0 million** accumulated deficit and **$86.2 million** cash - The company is a biopharmaceutical firm focused on developing and commercializing its lead product candidate, etripamil, a nasal spray for treating paroxysmal supraventricular tachycardia (PSVT), atrial fibrillation, and other cardiovascular indications[27](index=27&type=chunk) - As of June 30, 2022, the company had cash, cash equivalents, and short-term investments of **$86.2 million** and an accumulated deficit of **$237.0 million**[37](index=37&type=chunk) - No revenue was recognized in Q2 2022, unlike Q2 2021 which included **$15 million** in revenue from a non-refundable upfront cash payment related to a license agreement[38](index=38&type=chunk) Share-Based Compensation Expense (in thousands of US dollars) | Category | Three Months Ended June 30, 2022 | Six Months Ended June 30, 2022 | | :--- | :--- | :--- | | Administration | $880 | $1,792 | | Research and development | $1,105 | $1,953 | | Commercial activities | $426 | $780 | | **Total** | **$2,411** | **$4,525** | [Management's Discussion and Analysis of Financial Condition and Results of Operations](index=22&type=section&id=Item%202.%20Management%27s%20Discussion%20and%20Analysis%20of%20Financial%20Condition%20and%20Results%20of%20Operations) Management discusses etripamil's clinical progress and H1 2022 financial results, including a **$30.7 million** net loss Overview and Clinical Program Updates Milestone develops etripamil for cardiac arrhythmias, with the RAPID Phase 3 trial reaching its target events and data expected in H2 2022 - The pivotal Phase 3 RAPID trial for etripamil in PSVT reached its target of **180 confirmed events** in July 2022, with topline data anticipated in the mid-second half of 2022[61](index=61&type=chunk) - The open-label safety extension trial, NODE-302, showed a PSVT conversion rate of **60.2% at 30 minutes**, with a median time to conversion of **15.5 minutes**[68](index=68&type=chunk) - A Phase 2 proof-of-concept trial (ReVeRA) is ongoing to evaluate etripamil for reducing ventricular rate in patients with atrial fibrillation with rapid ventricular rate (AFib-RVR)[74](index=74&type=chunk) - Partner Ji Xing Pharmaceuticals initiated a Phase 3 study of etripamil for PSVT in China, enrolling the first patient in July 2022[71](index=71&type=chunk)[73](index=73&type=chunk) Results of Operations Q2 2022 operating loss was **$16.8 million** due to no revenue, and H1 2022 operating loss increased to **$30.9 million** Comparison of Operating Results (in thousands of US dollars) | Metric | Three Months Ended June 30, 2022 | Three Months Ended June 30, 2021 | Six Months Ended June 30, 2022 | Six Months Ended June 30, 2021 | | :--- | :--- | :--- | :--- | :--- | | Revenue | $0 | $15,000 | $0 | $15,000 | | R&D Expenses | $10,657 | $9,427 | $19,425 | $18,022 | | G&A Expenses | $3,918 | $3,018 | $7,561 | $5,651 | | Commercial Expenses | $2,231 | $1,843 | $3,867 | $3,209 | | **Earnings (loss) from operations** | **$(16,806)** | **$712** | **$(30,853)** | **$(11,882)** | - R&D expenses for the six months ended June 30, 2022 increased by **$1.4 million (7.8%)** year-over-year, primarily due to advancing the RAPID Phase 3 trials for etripamil in PSVT[100](index=100&type=chunk) - G&A expenses for the six months ended June 30, 2022 increased by **$1.9 million (33.8%)** year-over-year, mainly from a **$1.7 million** increase in personnel-related costs and consulting fees[103](index=103&type=chunk) Liquidity and Capital Resources As of June 30, 2022, the company had **$86.2 million** in cash and investments, expected to fund operations into H2 2023 - The company had **$86.2 million** in cash, cash equivalents, and short-term investments as of June 30, 2022[107](index=107&type=chunk) - Based on the current operating plan, the company expects its existing cash to be sufficient to fund operations into the **second half of 2023**[108](index=108&type=chunk) - Future funding needs are expected to be met through equity/debt financing or potential collaboration agreements, similar to the one with Ji Xing[113](index=113&type=chunk) [Quantitative and Qualitative Disclosures About Market Risk](index=42&type=section&id=Item%203.%20Quantitative%20and%20Qualitative%20Disclosures%20About%20Market%20Risk) The company faces interest rate and foreign currency risks, but a **10%** change in either is not expected to be material - The company is exposed to interest rate risk on its **$86.2 million** in cash, cash equivalents, and short-term investments, but a **10% change** in rates is not expected to be material due to the short-term nature of these assets[133](index=133&type=chunk) - The company is subject to foreign currency risk from transactions in Canadian dollars (CAD); as of June 30, 2022, net monetary exposure in CAD was **$2.8 million**, and a **10% change** is not expected to have a material effect[134](index=134&type=chunk)[136](index=136&type=chunk) [Controls and Procedures](index=42&type=section&id=Item%204.%20Controls%20and%20Procedures) Management concluded disclosure controls were effective as of June 30, 2022, with no material changes to internal controls - Management concluded that the company's disclosure controls and procedures were **effective** as of June 30, 2022[138](index=138&type=chunk) - There were **no material changes** during the quarter that materially affected the company's internal control over financial reporting[139](index=139&type=chunk) PART II. OTHER INFORMATION [Legal Proceedings](index=44&type=section&id=Item%201.%20Legal%20Proceedings) The company is not currently involved in any material legal proceedings or aware of any pending actions - The company is not currently involved in any material legal proceedings[141](index=141&type=chunk) [Risk Factors](index=44&type=section&id=Item%201A.%20Risk%20Factors) No material changes have occurred in the risk factors since the last Annual Report on Form 10-K - No material changes have occurred in the risk factors since the last Annual Report on Form 10-K[142](index=142&type=chunk) [Unregistered Sales of Equity Securities and Use of Proceeds](index=44&type=section&id=Item%202.%20Unregistered%20Sales%20of%20Equity%20Securities%20and%20Use%20of%20Proceeds) The company reported no unregistered sales of equity securities during the period - None[143](index=143&type=chunk) [Defaults Upon Senior Securities](index=44&type=section&id=Item%203.%20Defaults%20Upon%20Senior%20Securities) This section is not applicable to the company [Mine Safety Disclosures](index=44&type=section&id=Item%204.%20Mine%20Safety%20Disclosures) This section is not applicable to the company [Other Information](index=46&type=section&id=Item%205.%20Other%20Information) This section is not applicable to the company [Exhibits](index=46&type=section&id=Item%206.%20Exhibits) The report lists various exhibits filed, including corporate governance documents and CEO/CFO certifications - Exhibits filed include corporate governance documents, CEO/CFO certifications, and XBRL data files[146](index=146&type=chunk)

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, 2022 (State or other jurisdiction of incorporation or organization) Québec Not applicable (I.R.S. Employer Identification No.) 1111 Dr. Frederik-Philips Boulevard, Suite 420 Montréal, Québec CA H4M 2X6 (514) 336-0444 (Address, including zip code, and telephone number, inc ...

Corporate Overview March 24, 2022 Joseph Oliveto Chief Executive Officer Disclaimers The Presentation contains forward-looking statements within the meaning of the safe harbor provisions of the Private Securities Litigation Reform Act of 1995, as amended. Words such as ''aim,'' ''anticipate,'' ''assume,'' ''believe,'' ''contemplate,'' ''continue,'' ''could,'' ''design,'' ''due,'' ''estimate,'' ''expect,'' ''goal,'' ''intend,'' ''may,'' ''objective,'' ''plan,'' ''predict,'' ''positioned,'' ''potential,'' ''p ...

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K (Mark One) ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF For the fiscal year ended December 31, 2021 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) Québec Not applicable (State ...