Milestone Pharmaceuticals Inc.

Previous wording

We are a biopharmaceutical company focused on the development and commercialization of innovative cardiovascular medicines. Our objective is to commercialize and develop CARDAMYST (also known as etripamil) in the United States as a fast-acting, portable nasal spray treatment for use by patients anywhere, anytime an attack of supraventricular tachycardia, or “SVT” occurs. We are also developing etripamil for the indication of atrial fibrillation with rapid ventricular rate, or “AFib-RVR.”

Current wording

We are a biopharmaceutical company focused on the development and commercialization of innovative cardiovascular medicines. Our approved product CARDAMYSTTM (etripamil) nasal spray is available in the United States and is the first and only U.S. Food and Drug Administration, or the “FDA,” approved self-administered treatment for use by patients anywhere, anytime an attack of paroxysmal supraventricular tachycardia, or “PSVT,” occurs. We continue to seek, either directly or through collaboration with our partners, marketing approval from regulatory agencies responsible for regions outside the United States. We are also developing etripamil for the indication of atrial fibrillation with rapid ventricular rate, or “AFib-RVR”.

Previous wording

PSVT is a condition that causes a patient’s heart to suddenly start beating faster than normal. It can be life-altering as PSVT is highly symptomatic, characterized by unpredictable attacks of a racing heart, often exceeding 150 beats per minute. Symptoms of PSVT arise suddenly and may include palpitations, sweating, chest pressure or pain, shortness of breath, sudden onset of fatigue, lightheadedness or dizziness, fainting, and anxiety, causing many patients to interrupt their daily activities at the time of symptom-onset. The impact and morbidity from an episode of PSVT can be especially detrimental in patients with underlying cardiovascular or medical conditions, such as heart failure, obstructive coronary disease, or dehydration. The uncertainty of when such an attack of PSVT will strike or how long it will persist is often anxiety-provoking, reducing patients’ quality of life and preventing participation in many desired activities. Drugs approved for the treatment of attacks of PSVT include adenosine, verapamil, and diltiazem, with all being administered intravenously under medical supervision, usually in the emergency department. Other oral drugs are sometimes used to treat attacks in a concept called “pill in the pocket.” However, those drugs have never been proven effective or safe and are not approved for this use. Doctors are often frustrated by the lack of effective treatment options besides a prolonged, unpleasant, and costly trip to the emergency department or, for some patients, an invasive ablation procedure. PSVT can be traumatic for patients, frustrating for healthcare providers, and costly for payors. With no pharmaceutical innovation in the treatment of PSVT for more than 30 years and a movement in the healthcare system to enable patient-centered care, we believe there is an opportunity to help patients living with PSVT to take greater control over their PSVT.

Current wording

On December 12, 2025, we announced the FDA approved our first commercial product, CARDAMYST™ (etripamil) nasal spray, a prescription medication for the conversion of acute symptomatic episodes of PSVT to sinus rhythm in adults. We have currently begun focusing on the commercialization of CARDAMYST, which became available in retail pharmacies in the first quarter of 2026. PSVT is a condition that causes a patient’s heart to suddenly start beating faster than normal. It can be life-altering as PSVT is highly symptomatic, characterized by unpredictable attacks of a racing heart, often exceeding 150 beats per minute. Symptoms of PSVT arise suddenly and may include palpitations, sweating, chest pressure or pain, shortness of breath, sudden onset of fatigue, lightheadedness or dizziness, fainting, and anxiety, causing many patients to interrupt their daily activities at the time of symptom-onset. The impact and morbidity from an episode of PSVT can be especially detrimental in patients with underlying cardiovascular or medical conditions, such as heart failure, obstructive coronary disease, or dehydration. The uncertainty of when such an attack of PSVT will strike or how long it will persist is often anxiety-provoking, reducing patients’ quality of life and preventing participation in many desired activities. Drugs approved for the treatment of attacks of PSVT include adenosine, verapamil, and diltiazem, with all being administered intravenously under medical supervision, usually in the emergency department. Other oral drugs are sometimes used to treat attacks in a concept called “pill in the pocket.” However, those drugs have never been proven effective or safe and are not approved for this use. Doctors are often frustrated by the limited effective treatment options with the only approved options involving prolonged, unpleasant, and costly trips to the emergency department or, for some patients, an invasive ablation procedure. PSVT can be traumatic for patients, frustrating for healthcare providers, and costly for payors. With no pharmaceutical innovation in the treatment of PSVT for more than 30 years and a movement in the healthcare system to enable patient-centered care, we believe there is an opportunity to help patients living with PSVT to take greater control over their PSVT.

Previous wording

We believe that PSVT is a large and under-recognized market which we estimate affects more than two million Americans. From this diagnosed population, we define the immediate target addressable market for CARDAMYST as approximately 60% of patients who are actively managed by clinical cardiologists, interventional cardiologists and electrophysiologists. The remaining patients with PSVT can become addressable over time, as they are inconsistently managed (cycling in and out of the healthcare system) and/or being managed less frequently by primary care healthcare providers. Furthermore, PSVT is expected to increase in prevalence in coming years as wearable electrocardiogram, or “ECG,” technology (e.g., smartphone, watches) becomes both more adept at diagnosing PSVT and more widely used by patients and clinical practitioners, in turn shortening the current two to three year average time to diagnosis.

Current wording

We believe that PSVT is a large and under-recognized market which we estimate affects more than two million Americans. From this diagnosed population, we define the immediate target addressable market for CARDAMYST as approximately 50% of patients with PSVT who have sufficient disease burden that they are compelled to seek care for their condition and are primarily managed by approximately 40,000 healthcare providers composed primarily of clinical cardiologists, interventional cardiologists and electrophysiologists. The remaining patients with PSVT can become addressable over time, as they are inconsistently managed (cycling in and out of the healthcare system). Furthermore, PSVT is expected to

Previous wording

Current treatment for PSVT also consumes significant healthcare resources. Research published in the American Journal of Cardiology in 2020 shows that total healthcare expenditures in the year following a diagnosis of PSVT ranged from $20,000 to $30,000 per patient which were significantly higher than the expenditures observed for patients without PSVT. These significant increases included increased emergency department visits and hospitalization costs. Of note, catheter ablations following diagnosis represented only 23% of this increased spend, meaning most costs were unrelated to ablations. Recent data from the Healthcare Cost and Utilization Project (HCUP) database indicate that in 2019 there were approximately 140,000 emergency department, or “ED,” visits for PSVT when coded in the primary diagnostic position, and a total of approximately 525,000 ED visits when PSVT was coded in any diagnostic position. Of these, approximately 25% of ED admissions for PSVT resulted in a hospital admission. HCUP estimates a total of approximately 40,000 to approximately 120,000 inpatient admissions for PSVT in 2019 (based again if PSVT were found in the primary v. any diagnostic position). Despite the effectiveness of catheter ablation, claims data suggests that only approximately 15% of patients with PSVT are ablated over a three-year period, leading to a total of approximately 100,000 catheter ablations annually. In total, at least $5 billion is spent annually in the United States on the management of PSVT.

Current wording

Current treatment for PSVT also consumes significant healthcare resources. Research published in the American Journal of Cardiology in 2020 shows that total healthcare expenditures in the year following a diagnosis of PSVT ranged from $20,000 to $30,000 per patient which were significantly higher than the expenditures observed for patients without PSVT. These significant increases included increased emergency department visits and hospitalization costs. Of note, catheter ablations following diagnosis represented only 23% of this increased spend, meaning most costs were unrelated to ablations. Recent data from the Healthcare Cost and Utilization Project, or “HCUP,” database indicate that in 2019 there were approximately 140,000 emergency department, or “ED,” visits for PSVT when coded (for billing) in the primary diagnostic position, and a total of approximately 525,000 ED visits when PSVT was coded in any diagnostic position. Of these, approximately 25% of ED admissions for PSVT resulted in a hospital admission. HCUP estimates a total of approximately 40,000 to approximately 120,000 inpatient admissions for PSVT in 2019 (based again if a PSVT billing code was found in the primary versus any diagnostic position). Despite the effectiveness of catheter ablation, claims data suggests that only approximately 15% of patients with PSVT are ablated over a three-year period, leading to a total of approximately 100,000 catheter ablations annually. In total, up to $15.0 billion is spent annually in the United States on the management of PSVT.

Previous wording

In September 2024, our licensing partner, Corxel (formerly Ji Xing Pharmaceuticals Limited, JIXING), a clinical-stage biopharmaceutical company announced positive topline data from the Phase 3 JX02002 clinical trial of etripamil nasal spray in patients with PSVT in China.

Current wording

In January 2025, our licensing partner, Corxel Pharmaceuticals, or “Corxel,” formerly Ji Xing Pharmaceuticals Limited, JIXING, announced that the Center for Drug Evaluation, or “CDE,” of the National Medical Products Administration, or “NMPA,” of the People’s Republic of China has accepted the New Drug Application, or “NDA,” for etripamil nasal spray for the treatment of PSVT. The NDA to the NMPA included data from the successful Phase 3 JX02002 clinical trial of etripamil nasal spray in patients with PSVT in China in addition to data included in the NDA that Milestone submitted to the FDA.

Previous wording

The 500-patient Phase 3 trial (JX02002) met its primary endpoint, with a Kaplan Meier analysis shows a statistically significantly greater proportion of patients who self-administered etripamil converted from PSVT to sinus rhythm within 30 minutes compared to placebo (40.5% vs. 15.9%, respectively; hazard ratio [HR] = 3.00; 95% CI 1.58-5.71; p<0.001).

Current wording

The 500-patient Phase 3 trial (JX02002) met its primary endpoint, with a Kaplan Meier analysis shows a statistically significantly greater proportion of patients who self-administered etripamil converted from PSVT to sinus rhythm within 30 minutes compared to placebo (40.5% vs. 15.9%, respectively; hazard ratio [HR] = 3.00; 95% CI 1.58-5.71; p<0.001). Statistically significant (p<0.05) results were also shown for the secondary efficacy endpoints for percent of patients’ PSVT converted to sinus rhythm by 10, 15, 45 and 60 minutes after self-administration of study drug.

Previous wording

We are also developing etripamil nasal spray for a subsequent indication to treat patients with AFib-RVR. Similar to our approach for PSVT, we believe that etripamil has the potential to help the person experiencing a symptomatic episode of AFib-RVR to self-treat themselves and to conveniently, reliably, and quickly, reduce their elevated heart rate, with the goal of reducing the need for emergency department utilization. We completed a successful Phase 2 study in patients presenting urgently with AFib-RVR, i.e., to an emergency department. We publicly presented these positive Phase 2 data in November 2023, which demonstrated that patients receiving etripamil nasal spray experienced rapid and statistically superior ventricular rate reduction and improved symptom-relief compared to placebo, with safety and tolerability findings generally consistent with those observed in our PSVT program. This data supports the development of etripamil, self-administered in the medically unmonitored setting, for the treatment of AFib-RVR and, following dialogue with FDA, have finalized a Phase 3, potentially registrational study.

Current wording

Similar to our approach for PSVT, we believe that etripamil has the potential to help people experiencing a symptomatic episode of AFib-RVR to self-treat and to conveniently, reliably, and quickly reduce their elevated heart rate, with the goal of reducing the need for emergency department utilization. We completed a successful Phase 2 study, named “ReVeRA” or the “ReVeRA study”, in patients presenting urgently with episodes of AFib-RVR to the emergency department. We have published the ReVeRA study and results, which demonstrated that patients receiving etripamil nasal spray experienced rapid and statistically superior ventricular rate reduction and improved symptom-relief compared to placebo, with safety and tolerability findings generally consistent with those observed in our PSVT program. We believe these data support the continued development of etripamil, self-administered in the medically unmonitored setting, for the treatment of AFib-RVR.

Previous wording

Atrial Fibrillation, or “AFib,” is a common cardiac arrhythmia with an irregular and often rapid heart rate that is often markedly symptomatic and, without proper treatment, can increase the risk of stroke, heart failure, and other cardiovascular complications. A common complication of AFib is a rapid heart rate, also referred to as AFib-RVR, which is frequently defined as a heart rate ≥ 110 beats per minute. The occurrence of a rapid ventricular rate, or “RVR,” in patients with atrial fibrillation increases the likelihood of marked symptoms including heart palpitations, shortness of breath and weakness. There are two commonly used pharmacological approaches to chronically manage AFib, rhythm control and rate control. Regardless of the chronic approach, break-through episodes of rapid heart rate occur frequently; and when faced with a sudden episode of AFib-RVR, acute rate control is needed, with most treatments being AV-nodal targeted drugs such as a beta blocker or calcium channel blocker. These treatments can be given intravenously; however, this requires a burdensome trip to an emergency department which may lead to a hospital admission. Acute treatment can be attempted by administration of an oral rate control drug; however, such drugs do not adequately provide immediate or adequate ventricular rate control due to a 30- to 90-minute delayed onset of action, and, as a result, many patients need faster and more certain rate-reduction and symptom-resolution and so seek acute-medical care by going to the emergency department for treatment utilizing intravenous rate control and/or electrical cardioversion of their atrial fibrillation. Furthermore, the chronic administration of oral rate-control drugs does not broadly prevent episodes of AFib-RVR. Similar to PSVT, patients may feel a loss of control by needing to visit the emergency department for overcoming their AFib-RVR episode and the unpredictable nature of these episodes, which can occur anytime and anywhere. Doctors have expressed frustration

Current wording

Atrial Fibrillation, or “AFib,” is a common cardiac arrhythmia with an irregular and often rapid heart rate that is often markedly symptomatic and, without proper treatment, can increase the risk of stroke, heart failure, and other cardiovascular complications. A common complication of AFib is a rapid heart rate, also referred to as AFib-RVR, which is frequently defined as a heart rate ≥ 110 beats per minute. The occurrence of a rapid ventricular rate, or “RVR,” in patients with atrial fibrillation increases the likelihood of marked symptoms including heart palpitations, shortness of breath and weakness. There are two commonly used pharmacological approaches to chronically manage AFib, rhythm control and rate control. Regardless of the chronic approach, break-through episodes of rapid heart rate occur frequently; and when faced with a sudden episode of AFib-RVR, acute rate control is needed, with most treatments being AV-nodal targeted drugs such as a beta blocker or calcium channel blocker. These treatments can be given intravenously; however, this requires a burdensome trip to an emergency department which may lead to a hospital admission. Acute treatment can be attempted with an oral rate-control drug; however, such agents often fail to provide immediate or dependable ventricular rate control because they have a 30- to 90-minute delayed onset of action. As a result, many patients require faster and more reliable rate reduction and symptom resolution, leading them to seek acute medical care in the emergency department for intravenous rate control and/or electrical cardioversion of their atrial fibrillation. Furthermore, the chronic administration of oral rate-control drugs does not broadly prevent episodes of AFib-RVR. Similar to PSVT, patients may feel a loss of control by needing to visit the emergency department for overcoming their AFib-RVR episode and the unpredictable nature of these episodes, which can occur anytime and anywhere. Doctors have expressed frustration at the lack of options for patients to self-manage these acute rate attacks; and payor organizations would prefer to treat the AFib-RVR attacks in a more cost effective and time-efficient manner.

Previous wording

An estimated 10 million Americans suffer from AFib. The prevalence of AFib is expected to grow to greater than 12 million by 2030. A subset of patients with AFib experiences episodes of abnormally high heart rate, most often accompanied by palpitations, shortness of breath, dizziness, and weakness. While these episodes, known as AFib-RVR, may be treated by oral calcium channel blockers and/or beta blockers, patients frequently seek acute care in the ED to address symptoms. In 2019, nearly 1.1 million patients were admitted to the ED due to AFib symptoms. Initial data suggests that approximately 60% of all AFib ED visits were attributable to AFib-RVR, as symptoms driving patients to seek care generally become more pronounced at higher heart rates. Treatment for such symptoms typically includes medically supervised intravenous administration of calcium channel blockers or beta blockers, or electrical cardioversion. With little available data for AFib-RVR, we believe, based on our initial market research, that 30% to 40% of patients with AFib experience one or more symptomatic episodes of RVR per year that require treatment, suggesting a target addressable market of up to approximately four to five million patients by 2030 for etripamil in patients with AFib-RVR.

Current wording

An estimated 10 million Americans suffer from AFib. The prevalence of AFib is expected to grow to greater than 12 million by 2030. A subset of patients with AFib experiences episodes of abnormally high heart rate, most often accompanied by palpitations, shortness of breath, dizziness, and weakness. While these episodes, known as AFib-RVR, may be treated by oral calcium channel blockers and/or beta blockers, patients frequently seek acute care in the ED to address symptoms. In 2019, nearly 1.1 million patients were admitted to the emergency department due to AFib symptoms. Initial data suggests that approximately 60% of all AFib emergency department visits were attributable to AFib-RVR, as symptoms driving patients to seek care generally become more pronounced at higher heart rates. Treatment for such symptoms typically includes medically supervised intravenous administration of calcium channel blockers or beta blockers, or electrical cardioversion. With little available data for AFib-RVR, we believe, based on our initial market research, that 30% to 40% of patients with AFib experience one or more symptomatic episodes of RVR per year that require treatment, suggesting a current target addressable market of approximately three to four million patients for etripamil in patients with AFib-RVR.

Previous wording

We believe that etripamil has the potential to be developed such that it can be used by patients to rapidly reduce their heart rate at home, self-administered, to provide a supplemental option to either the acute oral rate or rhythm control strategy their physician would use. When presented with a target product profile reflecting this potential use case, cardiologists and electrophysiologists in a 2021 market research study perceived utility in the product profile and indicated that they would prescribe to approximately 67% of their patients that experience episodes of AFib-RVR. They further indicated that a rapidly-acting intranasal calcium channel blocker could serve as a “bridge” to the longer onset times of acute oral agents. According to physicians, it can take hours for patients to feel an alleviation of symptoms using acute oral rate or rhythm control. During this time, patients may experience concerning symptoms that often prompt them to seek emergency care. We believe that the combination of convenient delivery, potency, rapid onset and short duration of action of etripamil has the potential to move the current treatment setting for some acute episodes of AFib out of the burdensome and costly emergency department.

Current wording

We believe that etripamil has the potential to be developed such that it can be used by patients to rapidly reduce their heart rate to provide a supplemental option to either the acute oral rate or rhythm control strategy their physician would use. When presented with a target product profile reflecting this potential use case, cardiologists and electrophysiologists, in a 2021 market research study perceived utility in the product profile and indicated that they would prescribe to approximately two-thirds of their patients that experience episodes of AFib-RVR. They further indicated that a rapidly-acting intranasal calcium channel blocker could serve as a “bridge” to the longer onset times of acute oral agents. According to physicians, it can take hours for patients to feel an alleviation of symptoms using acute oral rate or rhythm control. During this time, patients may experience concerning symptoms that often prompt them to seek emergency care. We believe that the combination of convenient delivery, potency, rapid onset and short duration of action of etripamil has the potential to move the current treatment setting for some acute episodes of AFib out of the burdensome and costly emergency department.

Previous wording

During 2024, we met with the FDA on the ReVeRA study, during which the FDA confirmed its guidance from our Pre-IND meeting (2023) regarding the availability of a supplemental new drug application, or “sNDA,” pathway for the marketing approval for etripamil for the indication of AFib-RVR. The sNDA pathway potentially permits a single pivotal efficacy study to be sufficient for filing for marketing approval if etripamil is already approved for PSVT. FDA further concurred with respect to key proposed study elements including powering, inclusion criteria, patient population, and statistical analyses, and offered clarification with respect to the endpoints to guide the design of the Phase 3 study. In our mid-2023 Pre-IND meeting, the FDA provided guidance that our primary endpoint can be the reduction of ventricular rate, and the primary analysis would be performed on the intent to treat, or “ITT,” population. In addition, the study would have to show statistical significance (p<0.05) on the key secondary endpoint of symptom relief as a patient benefit, also in the ITT population. The secondary endpoint could use a PRO measure, and the application of a seven-point anchored scale was discussed with the FDA. We have finalized the Phase 3 study protocol following FDA’s review, obtained concurrence with the FDA to proceed, are operationally starting the study, and anticipating enrolling patients in 2025.

Current wording

During 2024, we met with the FDA on the ReVeRA study, during which the FDA confirmed its guidance from our Pre-IND meeting (2023) regarding the availability of a sNDA pathway for the marketing approval for etripamil for the indication of AFib-RVR. The sNDA pathway potentially permits a single pivotal efficacy study to be sufficient for filing for marketing approval if etripamil is already approved for PSVT. FDA further concurred with respect to key proposed study elements including powering, inclusion criteria, patient population, and statistical analyses, and offered clarification with respect to the endpoints to guide the design of the Phase 3 study. In our mid-2023 Pre-IND meeting, the FDA provided guidance that our primary endpoint can be the reduction of ventricular rate, and the primary analysis would be performed on the intent to treat, or “ITT,” population. In addition, the study would have to show statistical significance (p<0.05) on the key secondary endpoint of symptom relief as a patient benefit, also in the ITT population. The secondary endpoint could use a PRO measure, and various PROs were discussed with the FDA. We have finalized the Phase 3 study protocol following FDA’s review and obtained concurrence with the FDA to proceed.

Previous wording

Since the commencement of our operations in 2003, we have devoted substantially all of our resources to performing research and development activities in support of our product development efforts, hiring personnel, raising capital to support and expand such activities, providing general and administrative support for these operations and, more recently, preparing for commercialization. We operate our business using a significant outsourcing model. As such, our team is composed of a relatively smaller core of employees who direct a significantly larger number of team members who are outsourced in the forms of vendors and consultants to enable execution of our operational plans. We do not currently have any products approved for sale, and we continue to incur significant research and development and general administrative expenses related to our operations.

Current wording

Since the commencement of our operations in 2003, we have devoted substantially all of our resources to performing research and development activities in support of our product development efforts, hiring personnel, raising capital to support and expand such activities, providing general and administrative support for these operations and, more recently, preparing for commercialization. We have historically operated our business using a significant outsourcing model. As such, our team is currently composed of a relatively smaller core of employees who direct a significantly larger number of team members who are outsourced in the forms of vendors and consultants to enable execution of our operational plans. On December 12, 2025, we announced that the FDA approved our first commercial product, CARDAMYST™ (etripamil) nasal spray, a prescription medication for the conversion of acute symptomatic episodes of paroxysmal supraventricular tachycardia, or “PSVT,” to sinus rhythm in adults. As a result, we expectour future commercial expenses will increase as we invest in the infrastructure, personnel, and operational expenses required to commercialize CARDAMYST in the United States. We also expect inventory balances to increase as we capitalize costs related to the production of CARDAMYST for commercial sale in the United States. In addition, we expect to continue to incur significant research and development and general administrative expenses related to our operations as we advance etripamil nasal spray for the treatment AFib-RVR and continue to invest in the resources needed to support a developing commercialized public company.

Previous wording

Since inception, we have incurred significant operating losses. For the years ended December 31, 2024 and 2023, we recorded net losses of $41.5 million and $59.7 million, respectively. As of December 31, 2024, we had an accumulated deficit of $367.5 million. We expect to continue to incur significant losses for the foreseeable future. We anticipate that a substantial portion of our capital resources and efforts in the foreseeable future will be focused on completing the necessary development activities required for obtaining regulatory approval and preparing for potential commercialization of our product candidates. We had $25.3 million of cash and cash equivalents and $44.4 million of short-term investments at December 31, 2024.

Current wording

Since inception, we have incurred significant operating losses. For the years ended December 31, 2025 and 2024, we recorded net losses of $63.1 million and $41.5 million, respectively. As of December 31, 2025, we had an accumulated deficit of $430.6 million. We expect to continue to incur significant losses for the foreseeable future. We anticipate that a substantial portion of our capital resources and efforts in the foreseeable future will be focused on commercialization of CARDAMYST and the development of an additional etripamil indication. We had $73.0 million of cash and cash equivalents and $32.9 million of short-term investments at December 31, 2025.

Previous wording

We expect to continue to incur significant expenses and increasing operating losses for at least the next several years. Our net losses may fluctuate significantly from period to period, depending on the timing of our planned clinical trials and expenditures on other research and development activities. We expect our expenses will increase over time as we:

Current wording

We expect to continue to incur significant expenses and increasing operating losses for the foreseeable future. Our net losses may fluctuate significantly from period to period, depending on the timing of our planned clinical trials and expenditures on other research and development activities. We expect our expenses will increase over time as we:

Previous wording

Inflation rates may also materially adversely affect our business and corresponding financial position and cash flows. Inflationary factors, changes to interest rates and overhead costs may adversely affect our operating results. Interest and inflation rates also present a recent challenge impacting the U.S. economy and could make it more difficult for us to obtain traditional financing on acceptable terms, if at all, in the future. Additionally, geopolitical events such as the Russia-Ukraine war and unrest and/or further escalation in Israel and Gaza, recent banking instabilities, new or changing international tariffs, and other U.S. geopolitical issues affecting other territories and employee availability and wage increases, and economic markets all of which may result in additional stress on our working capital resources.

Current wording

Inflation rates may materially adversely affect our business and corresponding financial position and cash flows. Inflationary factors, changes to interest rates, and overhead costs may adversely affect our operating results. Interest and inflation rates also present a recent challenge impacting the U.S. economy and could make it more difficult for us to obtain traditional financing on acceptable terms, if at all, in the future. Additionally, geopolitical events, including war and terrorism, banking instabilities, ongoing changes to U.S. and international tariffs and other trade restrictions and trade barriers, renegotiation of international trade agreements, or further escalations of trade tensions, and other U.S. geopolitical issues affecting other territories and employee availability and wage increases, and economic markets all of which may result in additional stress on our working capital resources. The ongoing trade tensions between the U.S. and other jurisdictions have resulted in multiple rounds of tariffs and anticipated tariffs affecting pharmaceuticals and pharmaceutical ingredients, including finished drug products, manufacturing equipment, and related supplies. In any event, the dynamic and unpredictable tariff and trade landscape may create substantial uncertainty and planning challenges for our operations.

Previous wording

Research and development expenses consist primarily of salaries and fees paid to external service providers and also include personnel costs, including share-based compensation expense and other related compensation expenses. We expense research and development costs in the periods in which they are incurred. Costs for certain development activities are recognized based on an evaluation of the progress to completion of specific tasks using information and data provided to us by our vendors, collaborators and third-party service providers.

Current wording

Research and development expenses consist primarily of salaries and fees paid to external service providers, as well as personnel costs, including share-based compensation expense, and other related compensation expenses. We expense research and development costs in the periods in which they are incurred. Costs for certain development activities are recognized based on an evaluation of the progress to completion of specific tasks using information and data provided to us by our vendors, collaborators and third-party service providers.

Previous wording

To date, substantially all of our research and development expenses have been related to the preclinical and clinical development of etripamil. As we advance etripamil or other product candidates for other indications, we expect to allocate our direct external research and development costs across each of the indications or product candidates. Further, we expect our research and development costs to increase for the development of etripamil in atrial fibrillation with rapid ventricular rate, and we expect our research and development expenses related to the development of etripamil for PSVT decrease as a percentage of our total research and development expenses.

Current wording

To date, the majority of our research and development expenses have been related to the preclinical and clinical development of etripamil inclusive of manufacturing costs pre-FDA approval. As we advance etripamil or other product candidates for other indications, we expect to allocate our direct external research and development costs across each of the indications or product candidates. Further, we expect our research and development costs to increase for the development of etripamil in AFib-RVR, and we expect our research and development expenses related to the development of etripamil for PSVT to decrease as a percentage of our total research and development expenses.

Previous wording

General and administrative expenses include personnel and related compensation costs, expenses for outside professional services, lease expense, insurance expense and other general administrative expenses. Personnel costs consist of salaries, bonuses, benefits, related payroll taxes and share-based compensation. Outside professional services consist of legal, accounting and audit services and other consulting fees.

Current wording

General and administrative expenses include personnel and related compensation costs, expenses for outside professional services, lease expenses, insurance expenses and other general administrative expenses. Personnel costs consist of salaries, bonuses, benefits, related payroll taxes, and share-based compensation. Outside professional services consist of legal, accounting, and audit services and other consulting fees.

Previous wording

Commercial expenses consist primarily of personnel and related compensation costs, market and health economic research, and market development activities for PSVT and, to a lesser extent, AFib-RVR. The focus of these expenses is three-fold: first, we want to leverage rigorous primary and secondary research to fully understand our target disease states from the perspective of the patient, healthcare provider, and payer; second, we want to understand and document the burden of disease posed by PSVT and AFib-RVR from an epidemiology, healthcare resource use, and cost perspective; and third, we want to engage our target patient, physician, and payer stakeholders with evidence-based and compliant educational materials that serve to increase the awareness and understanding of the impact of PSVT and AFib-RVR on patients and the overall healthcare system.

Current wording

Commercial expenses consist primarily of personnel and related compensation costs, market and health economic research, and market development activities for PSVT and, to a lesser extent, AFib-RVR. The focus of these expenses is three-fold: first, we want to leverage rigorous primary and secondary research to fully understand our target disease states from the perspective of the patient, healthcare provider, and payer; second, we want to understand and document the burden of

Previous wording

If the FDA approves the NDA, we anticipate our commercial expenses will increase as we invest in the infrastructure, personnel, and operational expenses required to launch our first product in the United States.

Current wording

We anticipate our commercial expenses will increase as we invest in the infrastructure, personnel, and operational expenses required to commercialize CARDAMYST in the United States.

Previous wording

We recorded no revenue for the year ended December 31, 2024, compared to revenue of $1.0 million for the year ended December 31, 2023. This prior year revenue was the result of having reached a milestone pursuant to our License and Collaboration Agreement, dated May 15, 2021, with Corxel Pharmaceuticals, or “Corxel,” formerly known as Ji Xing Pharmaceuticals Limited, such party being referred to as “Ji Xing” and, such agreement, as the “Ji Xing License Agreement”, due upon the successful initiation of a Phase 1 Clinical Trial of a pharmaceutical product that uses a device to deliver etripamil by nasal spray by or on behalf of Corxel for the treatment of PSVT in the People’s Republic of China, or “the Territory,” including mainland China, Hong Kong Special Administrative Region, Macau Special Administrative Region and Taiwan.

Current wording

We recorded $1.5 million of license revenue for the year ended December 31, 2025, compared to no revenue recorded for the year ended December 31, 2024. The license revenue for the year ended December 31, 2025 was the result of having reached a milestone pursuant to our License and Collaboration Agreement, dated May 15, 2021, with Corxel Pharmaceuticals, or “Corxel,” formerly known as Ji Xing Pharmaceuticals Limited, such party being referred to as “Ji Xing” and, such agreement, as the “Ji Xing License Agreement,” due upon the successful NDA approval by the FDA for CARDAMYST for the treatment of PSVT in the United States.

Previous wording

General and administrative expenses increased $0.8 million, or 5.1%, for the for the year ended December 31, 2024, compared to the year ended December 31, 2023. This increase was driven primarily by an increase in outside service costs, partially offset by a decrease in personnel costs.

Current wording

General and administrative expenses increased $0.5 million, or 3.2%, for the year ended December 31, 2025, compared to the year ended December 31, 2024. This increase was driven primarily by an increase in outside service costs and higher personnel costs.

Previous wording

Interest income was $4.2 million and $4.0 million for the year ended December 31, 2024 and 2023, respectively. The increase in interest income was due to higher average interest rates earned on investments in 2024 when compared to 2023.

Current wording

Interest income was $2.9 million and $4.2 million for the year ended December 31, 2025 and 2024, respectively. The decrease in interest income in 2025 was driven decreasing interest rates and a smaller average investment balance in 2025 when compared to 2024.

Previous wording

We have incurred operating losses and experienced negative operating cash flows since our inception, and we anticipate continuing to incur losses for at least the next several years. As of December 31, 2024, we had cash, cash equivalents and short-term investments of $69.7 million and an accumulated deficit of $367.5 million.

Current wording

We have incurred operating losses and experienced negative operating cash flows since our inception, and we anticipate continuing to incur losses for the foreseeable future. As of December 31, 2025, we had cash, cash equivalents, and short-term investments of $106.0 million and an accumulated deficit of $430.6 million.

Previous wording

On February 28, 2024, we entered into an underwriting agreement, or the “Underwriting Agreement,” related to an underwritten public offering, or the “Offering,” of 16,666,667 of our common shares, without par value, at a public offering price of $1.50 per share and, in lieu of common shares to certain investors, pre-funded warrants to purchase 3,333,333 Shares at a public offering price of $1.499 per pre-funded warrant. Under the terms of the Underwriting Agreement, we granted the Underwriters an option to purchase up to an additional 3,000,000 common shares at the same price per share as the other common shares sold in the Offering, which was exercised by the Underwriters in full on February 29, 2024.

Current wording

On February 28, 2024, we entered into an underwriting agreement related to an underwritten public offering, or the “February 2024 Offering,” of 16,666,667 of our common shares, without par value, at a public offering price of $1.50 per share and, in lieu of common shares to certain investors, pre-funded warrants to purchase 3,333,333 common shares, or the “2024 Pre-Funded Warrants,” at a public offering price of $1.499 per 2024 Pre-Funded Warrants. Each of the 2024 Pre-Funded Warrants has an exercise price of $0.001 per share. The 2024 Pre-Funded Warrants were exercisable immediately upon issuance, subject to certain beneficial ownership limitations. Under the terms of the agreement, we granted the underwriters party thereto an option to purchase up to an additional 3,000,000 common shares at the same price per share as the other common shares sold in this offering, which was exercised by such underwriters in full on February 29, 2024.

Previous wording

The net proceeds to the Company from the Offering, including the proceeds from the exercise by the Underwriters of their option to purchase the additional 3,000,000 common shares in full, was $31.9 million after deducting underwriting commissions and offering expenses payable by the Company.

Current wording

The net proceeds to us from the February 2024 Offering, including the proceeds from the exercise by the underwriters of their option to purchase the additional 3,000,000 common shares in full, was $31.9 million after deducting underwriting commissions and offering expenses payable by us.

Previous wording

On July 29, 2020, we entered into an Open Market Sale Agreement SM, or the “Sales Agreement,” with respect to an at-the-market offering program, or the “ATM Program,” under which the Company may issue and sell its common shares having an aggregate offering price of up to $50 million through Jefferies as its sales agent or principal. On May 31, 2023, we filed a prospectus supplement (File No. 333-261049) that amended and restated the information in our prospectus supplement dated July 29, 2020, and, accordingly, the information in this prospectus supplement superseded the information contained in that prospectus supplement, or the prior prospectus supplement. Pursuant to that prior prospectus supplement and accompanying base prospectus contained in our Registration Statement on Form S-3 (File No. 333-239318), we issued 361,236 common shares under the Sales Agreement, resulting in net proceeds of $2.6 million (net of issuance costs of $0.1 million). No common shares were sold under the Sales Agreement during the year ended December 31, 2024.

Current wording

On July 29, 2020, we entered into an Open Market Sale Agreement SM, or the “Original Sale Agreement,” with respect to an at-the-market offering program, or the “ATM Program,” under which we could issue and sell our common shares having an aggregate offering price of up to $50.0 million through Jefferies LLC, or “Jefferies,” as sales agent or principal. On March 18, 2025, we entered into an Amended and Restated Open Market Sale Agreement SM, or the “Amended Agreement,” with Jefferies. The Amended Agreement amends and restates, in its entirety, the Original Sale Agreement. Under the Amended Agreement, we may issue and sell its common shares, no par value per share, for an aggregate offering price of up to $77.8 million (which includes the $2.8 million of sales previously made pursuant to the Original Sale Agreement through the date the Amended Agreement was entered into), or the “ATM Shares.” The ATM Shares will be sold pursuant to our shelf registration statement on Form S-3 (File No. 333-283162). We previously issued 361,236 common shares under the Original Sale Agreement, resulting in net proceeds of approximately $2.6 million (net of issuance costs of approximately $0.1 million). We issued 5,690,920 shares under the amended agreement resulting in net proceeds of $14.5 million, after deducting sales agent commissions payable by us of $0.4 million, during the year ended December 31, 2025.

Previous wording

Pursuant to the Royalty Purchase Agreement, RTW agreed to purchase, following FDA approval of etripamil (subject to certain conditions), in exchange for a purchase price of $75.0 million, the right to receive a tiered quarterly royalty payments, or “royalty interest,” on the annual net product sales of etripamil in the United States. This represents a contingent future source of funding, in order for the Company to receive the $75 million, the closing conditions specified in the Royalty Purchase Agreement, which includes the Company receiving marketing approval from the FDA on or prior to September 30, 2025, must be met.

Current wording

Pursuant to the Royalty Purchase Agreement, RTW agreed to purchase, following FDA approval of etripamil (subject to certain conditions), in exchange for a purchase price of $75.0 million, the right to receive a tiered quarterly royalty payments, or “royalty interest,” on the annual net product sales of etripamil in the United States.

Previous wording

We use our cash primarily to fund research and development expenditures. We expect our expenses to increase as we continue the development of etripamil and prepare for regulatory approval. We expect to incur increasing operating losses for the foreseeable future as we continue the clinical development of our product candidate. At this time, due to the inherently unpredictable nature of clinical development, we cannot reasonably estimate the costs we will incur and the timelines that will be required to complete development, obtain marketing approval, and commercialize etripamil or any future product candidates, if at all. For the same reasons, we are also unable to predict when, if ever, we will generate revenue from product sales or whether, or when, if ever, we may achieve profitability. Clinical and preclinical development timelines, the probability of success, and development costs can differ materially from expectations.

Current wording

We anticipate that we will use our cash and cash equivalents primarily to fund commercialization and research and development expenditures. We expect our expenses to increase as we continue the development of etripamil and invest in the infrastructure, personnel, and operational expenses required to commercialize CARDAMYST in the United States. We expect to incur increasing operating losses for the foreseeable future as we continue the clinical development of subsequent etripamil indications or any future product candidates. At this time, due to the inherently unpredictable nature of clinical development, we cannot reasonably estimate the costs we will incur and the timelines that will be required to complete development, obtain marketing approval, and commercialize subsequent etripamil indications or any future product candidates, if at all. For the same reasons, we are also unable to predict when, if ever, we may achieve profitability generated from product sales. Clinical and preclinical development timelines, the probability of success, and development costs can differ materially from expectations.

Previous wording

In addition, we have exclusive development and commercialization rights for etripamil for all indications that we may pursue and as such have the potential to license development and or commercialization rights for etripamil to a potential partner in regions outside of Greater China. We plan to establish commercialization and marketing capabilities using a direct sales force to commercialize etripamil in the United States. Outside of the United States, we are considering commercialization strategies that may include collaborations with other companies.

Current wording

In addition, we have exclusive development and commercialization rights for etripamil for all indications that we may pursue, and as such, have the potential to license development and or commercialization rights for etripamil to a potential partner in regions outside of Greater China. We have established commercialization and marketing capabilities using a direct sales force to commercialize CARDAMYST in the United States. Outside of the United States, we are considering commercialization strategies that may include collaborations with other companies.

Previous wording

Until such time, if ever, as we can generate substantial revenue from product sales, we expect to fund our operations and capital funding needs through equity and/or debt financing. We may also consider entering into collaboration arrangements or selectively partnering for clinical development and commercialization. The sale of additional equity would result in additional dilution to our shareholders. The incurrence of debt financing would result in debt service obligations and the instruments governing such debt could provide for operating and financing covenants that restrict our operations or our ability to incur additional indebtedness or pay dividends, among other items. If we are not able to secure adequate additional funding, we may be forced to make reductions in spending, extend payment terms with suppliers, liquidate assets where possible, and/or suspend or curtail planned programs. Any of these actions could materially and adversely affect our business, financial condition and results of operations.

Current wording

instruments governing such debt could provide for operating and financing covenants that restrict our operations or our ability to incur additional indebtedness or pay dividends, among other items. If we are not able to secure adequate additional funding, we may be forced to make reductions in spending, extend payment terms with suppliers, liquidate assets where possible, and/or suspend or curtail planned programs. Any of these actions could materially and adversely affect our business, financial condition and results of operations.

Previous wording

Net cash used in operating activities during the year ended December 31, 2023, was $46.4 million, which consisted primarily of a net loss of $59.7 million. The net loss was partially offset by a net cash increase of $1.2 million related to the change in assets and liabilities, non-cash charges of $9.5 million related to share-based compensation and non-cash interest charges of $2.3 million related to the 2029 Convertible Notes.

Current wording

Net cash used in operating activities during the year ended December 31, 2025, was $49.0 million, which consisted primarily of a net loss of $63.1 million. The net loss was partially offset by a net cash increase of $2.7 million related to the change in assets and liabilities, non-cash charges of $7.5 million related to share-based compensation and non-cash interest and debt charges of $3.8 million related to the 2029 Convertible Notes.

Previous wording

During the year ended December 31, 2023, we redeemed $142.0 million of short-term investments, and we acquired $137.1 million of short-term investments. In addition, we acquired $0.1 million in property and equipment.

Current wording

During the year ended December 31, 2025, we redeemed $94.5 million of short-term investments, and we acquired $82.9 million of short-term investments. In addition, we acquired $0.3 million in property and equipment.

Previous wording

During the year ended December 31, 2024, our financing activities provided cash proceeds of $32.1 million. These proceeds were primarily a result of the $31.9 million received from the issuance of common shares and pre-funded warrants, net of $2.6 million in issuance costs paid under the Underwriting Agreement.

Current wording

During the year ended December 31, 2024, our financing activities provided cash proceeds of $32.1 million. These proceeds were primarily a result of the $31.9 million received from the issuance of common shares and pre-funded warrants, net of $2.6 million in issuance costs paid under the February 2024 Offering.

Previous wording

We enter into contracts in the normal course of business with clinical research organizations, or “CROs,” contract manufacturing organizations, or “CMOs,” and other third parties for clinical trials, preclinical research studies and testing and manufacturing services. These contracts are generally cancelable at our option with various notice requirements as defined in the contract. Payments due upon cancellation consist of payments for services provided or expenses incurred, including noncancelable obligations of our service providers, up to and through the date of cancellation. These payments are not included as the amount and timing of these payments are not known.

Current wording

manufacturing organizations, or “CMOs,” and other third parties for clinical trials, preclinical research studies, and testing and manufacturing services. These contracts are generally cancelable at our option with various notice requirements as defined in the contract. Payments due upon cancellation consist of payments for services provided or expenses incurred, including noncancelable obligations of our service providers, up to and through the date of cancellation. These payments are not included as the amount and timing of these payments are not known.

Previous wording

Research and development costs are charged against income in the period of expenditure. Our research and development costs consist primarily of salaries and fees paid to CROs and to CMO.

Current wording

Research and development costs are charged against income in the period of expenditure. Our research and development costs consist primarily of salaries and fees paid to CROs and to CMO for clinical trial expenses and manufacturing costs prior to FDA approval.

Previous wording

Clinical trial expenses include direct costs associated with CROs, direct CMO costs for the formulation and packaging of clinical trial material, as well as investigator and patient-related costs at sites at which our trials are being conducted. Direct costs associated with our CROs and CMOs are generally payable on a time-and-materials basis, or when milestones are achieved. The invoicing from clinical trial sites can lag several months. We record expenses for our clinical trial activities performed by third parties based upon estimates of the percentage of work completed of the total work over the life of the individual trial in accordance with agreements established with CROs and clinical trial sites. We determine the estimates through discussions with internal clinical personnel, CROs and CMOs as to the progress or stage of completion of trials or services and the agreed-upon fee to be paid for such services based on facts and circumstances known to us as of each consolidated balance sheet date. The actual costs and timing of clinical trials are highly uncertain, subject to risks and may change depending upon a number of factors, including our clinical development plan. If the actual timing of the performance of services of the level of effort varies from the estimate, we will adjust the accrual accordingly. Adjustments to prior period estimates have not been material. We recognize the benefit of Canadian research and development tax credits as a reduction of research and development costs for fully refundable investment tax credits and as a reduction of income taxes for investment tax credits that can only be claimed against income taxes payable when there is reasonable assurance that the claim will be recovered.

Current wording

Clinical trial expenses include direct costs associated with CROs, direct CMO costs for the formulation and packaging of clinical trial material, as well as investigator and patient-related costs at sites at which our trials are being conducted. Direct costs associated with our CROs and CMOs are generally payable on a time-and-materials basis, or when milestones are achieved. The invoicing from clinical trial sites can lag several months. We record expenses for our clinical trial activities performed by third parties based upon estimates of the percentage of work completed of the total work over the life of the individual trial in accordance with agreements established with CROs and clinical trial sites. We determine the estimates through discussions with internal clinical personnel, CROs, and CMOs as to the progress or stage of completion of trials or services and the agreed-upon fee to be paid for such services based on facts and circumstances known to us as of each consolidated balance sheet date. The actual costs and timing of clinical trials are highly uncertain, subject to risks and may change depending upon a number of factors, including our clinical development plan. If the actual timing of the performance of services and of the level of effort varies from the estimate, we will adjust the accrual accordingly. Adjustments to prior period estimates have not been material. We recognize the benefit of Canadian research and development tax credits as a reduction of research and development costs for fully refundable investment tax credits and as a reduction of income taxes for investment tax credits that can only be claimed against income taxes payable when there is reasonable assurance that the claim will be recovered.