Milestone Pharmaceuticals Reports Third Quarter 2021 Financial Results and Provides Clinical and Corporate Update Montreal and Charlotte, N.C.

Milestone Pharmaceuticals

Reports Third Quarter 2021 Financial Results and Provides Clinical and Corporate Update

Montreal and Charlotte,

N.C., Nov. 12, 2021 -- Milestone Pharmaceuticals Inc. (Nasdaq: MIST), a biopharmaceutical company focused

on the development and commercialization of innovative cardiovascular medicines, today reported financial results for the third quarter

ended September 30, 2021 and provided a clinical and corporate update.

to make meaningful progress across our etripamil PSVT program. We've advanced our Phase 3 efficacy and safety studies and completed

important patient research which enables a deeper understanding and characterization of the burden experienced by patients," said

Joseph Oliveto, President and Chief Executive Officer of Milestone Pharmaceuticals. "Additionally, we look forward to presenting

data from an analysis of heart rate in patients treated in the NODE-301 trial at the upcoming AHA Scientific Sessions 2021 meeting. We

believe these data underscore the potential of etripamil to serve as an important intervention for patients with episodic cardiovascular

trial, which is targeting a total of 180 adjudicated PSVT events, is expected to randomize approximately 500 patients 1:1 to receive either

etripamil or placebo. To maximize the potential treatment effect of etripamil, patients will be directed to administer a repeat dose of

study drug if they do not experience symptom relief within 10 minutes of the first study drug administration. The primary efficacy analysis

for both the RAPID trial and the completed NODE-301 trial will be time to conversion of supraventricular tachycardia (SVT) over the first

30 minutes following initial study drug administration, with a target p-value of less than 0.05 for each trial. The RAPID and NODE-301

trials could potentially serve to fulfill the efficacy requirement for a future New Drug Application (NDA) for etripamil in patients with

Patients who participated in the study

demonstrated a wide range of annual SVT episode frequency (0 to >50), with a median frequency of 12-15 episodes per year. Based on

internal analysis, Milestone estimates approximately 60% of patients experience multiple 10+ minute episodes each year characterized as

moderate or severe in intensity. In addition, approximately 30% of patients experiencing episodes sought medical care for the episode,

the majority of which were treated in the emergency department.

Supraventricular Tachycardia

Paroxysmal supraventricular

tachycardia (PSVT) is a condition characterized by intermittent episodes of rapid heart beat that starts and stops suddenly and without

warning that affects approximately two million Americans. Episodes of supraventricular tachycardia (SVT) are often associated with palpitations,

sweating, chest pressure or pain, shortness of breath, sudden onset of fatigue, lightheadedness or dizziness, fainting, and anxiety. Adenosine

and certain calcium channel blockers have long been approved for the treatment of PSVT. However, these medications must be administered

intravenously under medical supervision, usually in an emergency department or other acute care setting.

About Atrial Fibrillation

with Rapid Ventricular Rate

(AFib) is a common arrhythmia marked by an irregular and often rapid heartbeat. AFib is estimated to affect five million patients in the

United States, a prevalence projected by the Centers for Disease Control to increase to twelve million patients within the next 10 years.

Atrial fibrillation with rapid ventricular rate (AFib-RVR) is a condition in which patients with AFib experience episodes of abnormally

high heart rate, often with symptoms such as palpitations, shortness of breath, dizziness, and weakness. Oral calcium channel blockers

and/or beta blockers are commonly used to manage the heart rate in this condition. When episodes do occur, the corresponding symptoms

often cause patients to seek care in the acute care setting such as the emergency department, where standard of care procedures include

intravenous administration of calcium channel blockers or beta blockers under medical supervision. Milestone's initial qualitative

market research indicates that approximately 40% of patients with AFib experience one or more symptomatic episodes of RVR per year that

require treatment, suggesting a target addressable market for etripamil in patients with AFib of approximately two million patients.

Etripamil, Milestone's

lead investigational product, is a novel calcium channel blocker designed to be a rapid-response therapy for episodic cardiovascular conditions.

As a nasal spray that is self-administered by the patient, etripamil has the potential to shift the current treatment experience for many

patients from the emergency department to the at-home setting. Milestone is conducting a comprehensive development program for etripamil,

with Phase 3 trials ongoing in paroxysmal supraventricular tachycardia (PSVT) and now a Phase 2 proof-of-concept trial underway in patients

with atrial fibrillation and rapid ventricular rate (AFib-RVR).

Milestone Pharmaceuticals

Inc. (Nasdaq: MIST), is a biopharmaceutical company focused on the development and commercialization of innovative cardiovascular medicines.

Milestone's lead product candidate etripamil is currently in a Phase 3 clinical-stage program for the treatment of paroxysmal supraventricular

tachycardia (PSVT) and in a Phase 2 proof-of-concept trial for the treatment of patients with atrial fibrillation and rapid ventricular

rate (AFib-RVR). Milestone Pharmaceuticals operates in Canada and the United States. For more information, visit www.milestonepharma.com

and follow the Company on Twitter at @MilestonePharma.

This press release contains forward-looking statements

within the meaning of the Private Securities Litigation Reform Act of 1995. Words such as "believe," "will," "expect,"

"continue," "estimate," "potential," "progress" 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 potential of etripamil to serve as a promising therapy for

PSVT patients, the design, progress, timing, scope and results of the RAPID and ReVeRA trials; Milestone's ability to execute on

the remainder of the PSVT program, Milestone's ongoing plans to study etripamil in atrial fibrillation patients, the sufficiency

of Milestone's current cash resources to support its operations, and estimates about the addressable market and commercial potential

for treatments of atrial fibrillation with rapid ventricular rate. Important factors that could cause actual results to differ materially

from those in the forward-looking statements include, but are not limited to, 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 and evaluation of clinical trials, and whether the clinical trials will validate the safety and efficacy of etripamil

for PSVT or other indications, among others, as well as risks related to pandemics and public health emergencies, including those related

to the ongoing COVID-19 pandemic, and risks related the sufficiency of Milestone's capital resources and its ability to raise additional

capital. These and other risks are set forth in Milestone's filings with the U.S. Securities and Exchange Commission, including in its

annual report on Form 10-K for the year ended December 31, 2020, under the caption "Risk Factors." 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.

INTERIM CONDENSED CONSOLIDATED STATEMENTS

OF LOSS AND COMPREHENSIVE LOSS

(Unaudited, in thousands of US dollars,

except share and per share data)

INTERIM CONDENSED CONSOLIDATED BALANCE

(Unaudited, in thousands of US dollars,