Form 8-K

8-K — Milestone Pharmaceuticals Inc.

Accession: 0001104659-26-105052

Filed: 2026-09-03

Period: 2026-09-03

CIK: 0001408443

SIC: 2834 (PHARMACEUTICAL PREPARATIONS)

Item: Other Events

Item: Financial Statements and Exhibits

Documents

8-K — tm2624766d1_8k.htm (Primary)

EX-99.1 — EXHIBIT 99.1 (tm2624766d1_ex99-1.htm)

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UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the

Securities Exchange Act of 1934

Date of Report (Date of earliest event reported):

September

3, 2026

MILESTONE

PHARMACEUTICALS INC.

(Exact name of registrant as specified in its

charter)

Québec

001-38899

Not

applicable

(state or other jurisdiction of incorporation)

(Commission File Number)

(I.R.S. Employer Identification No.)

1111

Dr. Frederik-Philips Boulevard,

Suite

420

Montréal,

Québec CA

H4M

2X6

(Address of principal executive offices)

(Zip Code)

Registrant's telephone number, including area

code: (514)

336-0444

(Former

name or former address, if changed since last report.)

Check the appropriate box below if the Form 8-K

filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General

Instruction A.2. below):

¨ Written

communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

¨ Soliciting

material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

¨ Pre-commencement

communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

¨ Pre-commencement

communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b)

of the Act:

Title of each class

Trading Symbol(s)

Name of each exchange on which

registered

Common

MIST

The

Nasdaq Stock Market LLC

Indicate by check mark

whether the registrant is an emerging growth company as defined in as defined in Rule 405 of the Securities Act of 1933 (§ 230.405

of this chapter) or Rule 12b–2 of the Securities Exchange Act of 1934 (§ 240.12b–2 of this chapter).

Emerging growth company

If an emerging growth

company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or

revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ¨

Item 8.01

Other Events

On September

3, 2026, Milestone Pharmaceuticals Inc. issued a press release announcing that China’s National Medical Products Administration

has approved etripamil nasal spray for the treatment of paroxysmal supraventricular tachycardia (PSVT) in adults. A copy of the press

release is filed herewith as Exhibit 99.1 to this Current Report on Form 8-K and incorporated herein by reference.

Item

9.01

Financial

Statements and Exhibits

(d) Exhibits.

Exhibit Number

Description of Exhibit

99.1

Press Release dated September 3, 2026

104

Cover Page Interactive Data (embedded within the Inline XBRL document)

SIGNATURES

Pursuant to the requirements

of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto

duly authorized.

MILESTONE PHARMACEUTICALS INC.

By:

/s/Amit Hasija

Amit Hasija

Chief Financial Officer

Dated: September 3, 2026

EX-99.1 — EXHIBIT 99.1

EX-99.1

Filename: tm2624766d1_ex99-1.htm · Sequence: 2

Exhibit 99.1

Milestone Pharmaceuticals Announces NMPA Approval

of Etripamil Nasal Spray for PSVT in China, Marking First Regulatory Approval of Etripamil Outside of the United States

Everest Medicines to Lead Commercialization

in Greater China, Bringing Novel Innovation to Estimated 3-6 Million Chinese Patients with PSVT

Approval Triggers $2.0 Million Payment to Milestone

Pharmaceuticals

MONTREAL and CHARLOTTE, N.C., –

September 3, 2026 – Milestone® Pharmaceuticals Inc. (Nasdaq: MIST), a biopharmaceutical company focused on

the development and commercialization of innovative cardiovascular medicines, today announced that China’s National Medical Products

Administration (NMPA) has approved etripamil nasal spray for the treatment of paroxysmal supraventricular tachycardia (PSVT) in adults.

Etripamil, marketed in the United States as CARDAMYST® nasal spray, is a self-administered treatment for adults with PSVT.

The NMPA decision marks the first regulatory

approval of etripamil outside the United States and triggers a $2.0 million milestone payment to Milestone Pharmaceuticals. Everest

Medicines has an exclusive license with Milestone to develop etripamil nasal spray in Greater China (including Mainland China, Hong

Kong, Macau and Taiwan). Under the License Agreement with Everest, Milestone is also eligible to receive up to $98.0 million in commercial

and development milestones and tiered royalties of up to 18% on future sales of etripamil in Greater China.

The NMPA approval was based on data from the

global pivotal Phase 3 RAPID study and the Phase 3 JX02002 study conducted in China. JX02002 met its primary endpoint, demonstrating

that etripamil was significantly superior to placebo in converting PSVT to sinus rhythm within 30 minutes of treatment (hazard ratio

= 3.002 [95% CI: 1.578, 5.711]; p = 0.0005). Overall, treatment-emergent adverse events were comparable between the etripamil and placebo

groups, and no serious adverse events were reported within 24 hours after dosing across Phase 3 studies.

“We believe the approval of etripamil nasal

spray in China represents exciting progress toward our vision to help patients around the world living with PSVT,” said Joseph

Oliveto, President and Chief Executive Officer of Milestone Pharmaceuticals. “We congratulate Everest on this achievement and look

forward to continued collaboration as they launch the product in this important market.”

About Paroxysmal Supraventricular Tachycardia

(PSVT)

An estimated three to six million people in

China and two million people in the United States are currently diagnosed with PSVT, which is a type of arrhythmia or abnormal heart

rhythm. PSVT is characterized by episodes of sudden onset rapid heartbeats often exceeding 150 to 200 beats per minute. The heart

rate spike is unpredictable and may last several hours. The rapid heart rate often causes disabling severe palpitations, shortness

of breath, chest discomfort, dizziness or lightheadedness, and distress, forcing patients to limit their daily activities. The

uncertainty of when an episode of PSVT will strike or how long it will persist can provoke anxiety in patients and negatively impact

their day-to-day life between episodes. The impact and morbidity from an attack can be especially detrimental in patients with

underlying cardiovascular or medical conditions, such as heart failure, obstructive coronary disease, or dehydration. Many health

care providers are dissatisfied with the lack of effective treatment options, with patients often electing to pursue prolonged,

burdensome, and costly trips to the emergency department or even undergo invasive cardiac ablation procedures.

About CARDAMYST in the United States

CARDAMYST® (etripamil) nasal spray is approved

by the U.S. Food and Drug Administration (FDA) for the conversion of acute symptomatic episodes of paroxysmal supraventricular

tachycardia (PSVT) to sinus rhythm in adults. It is a novel calcium channel blocker nasal spray designed as a self-administered rapid

response therapy for patients, thereby bypassing the need for immediate medical oversight. The product is intended to provide health

care providers with a new treatment option to enable on-demand care and patient self-management. This portable treatment may provide

patients with active management and a greater sense of control over their condition. CARDAMYST is well studied with a robust clinical

trial program that includes a completed Phase 3 clinical-stage program for the treatment of PSVT. Currently, etripamil is in Phase 2

development for treatment of PSVT in pediatric patients and Phase 3 development for control of acute atrial fibrillation with rapid ventricular

rate (AFib-RVR) in adults. For more information, please visit CARDAMYST.com.

U.S. FDA Indication

CARDAMYST is indicated for the conversion

of acute symptomatic episodes of paroxysmal supraventricular tachycardia (PSVT) to sinus rhythm in adults.

IMPORTANT SAFETY INFORMATION FOR CARDAMYST

(etripamil)

What is CARDAMYST?

CARDAMYST is a prescription medicine used

to help restore normal sinus heart rhythm in adults who have symptoms of sudden episodes of fast heartbeat called paroxysmal supraventricular

tachycardia (PSVT).

It is not known if CARDAMYST is safe and effective

in children.

Do not use CARDAMYST if you:

· are

allergic to CARDAMYST or any of its ingredients. See the Patient Information for a complete

list of ingredients in CARDAMYST.

· have

limitations in activities due to heart failure (moderate to severe heart failure).

· have

Wolff-Parkinson-White (WPW) syndrome, Lown-Ganong-Levine syndrome, or an abnormal heart rhythm

pattern called pre-excitation (delta wave) on an electrocardiogram (ECG).

· have

sick sinus syndrome without a permanent pacemaker.

· have

second degree or higher atrioventricular (AV) block.

Before using CARDAMYST, tell your healthcare

provider about all of your medical conditions, including if you:

· have

a history of fainting.

· have

low blood pressure.

· are

pregnant or plan to become pregnant. It is not known if CARDAMYST will harm your unborn baby.

· are

breastfeeding or plan to breastfeed. It is not known if CARDAMYST passes into your breast

milk. You should stop breastfeeding for 12 hours after treatment with CARDAMYST. During this

time, pump and throw away your breast milk. Talk to your healthcare provider about the best

way to feed your baby after using CARDAMYST.

Tell your healthcare provider about all the

medicines you take, including prescription and over-the-counter medicines, vitamins, and herbal supplements.

What are the possible side effects of CARDAMYST?

CARDAMYST may cause serious side effects,

including:

· Fainting

due to CARDAMYST effects on blood pressure, heart rate, and electrical activity of the heart. CARDAMYST may cause dizziness

and fainting, especially in people with a history of fainting and certain heart problems, or people with a history of fainting during

an episode of PSVT. Use CARDAMYST while sitting in a safe area where you will not fall if you become dizzy or lightheaded. Lie down if

you feel dizzy or lightheaded after using CARDAMYST. If fainting occurs after using CARDAMYST, caregivers should place you on your back

and seek medical help.

The most common side effects of CARDAMYST

include:

· nasal

discomfort

throat

irritation

· nasal

congestion

nosebleed

· runny

nose

These are not all of the possible side effects for CARDAMYST. Call your doctor for medical advice about side effects. You may report

side effects to FDA at 1-800-FDA-1088.

Please see the full Prescribing Information

https://milestonepharma.com/etripamilprescribinginformation.pdf

for CARDAMYST.

About Milestone

Pharmaceuticals

Milestone Pharmaceuticals Inc. (Nasdaq:

MIST) is an emerging commercial-stage biopharmaceutical company advancing innovative cardiovascular medicines to benefit people living

with certain heart conditions. Milestone’s lead product is CARDAMYST® (etripamil) nasal spray, a novel calcium channel

blocker, which is FDA-approved for the conversion of acute symptomatic episodes of paroxysmal supraventricular tachycardia (PSVT) to

sinus rhythm in adults. Etripamil is also in Phase 3 development for the control of symptomatic episodic attacks associated with AFib-RVR.

https://milestonepharma.com/

Cautionary Note on 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 commercialization and adoption of CARDAMYST; the ability of Milestone to receive up to $98 million in milestone payments and royalties

on future sales of etripamil in Greater China; the expected timing of initiation, completion, and results and data of Milestone’s

ongoing and planned clinical studies, including the Phase 3 study in 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, 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 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, international

tariffs and conflicts, and overall fluctuations in the financial markets in the United States and abroad, risks related to pandemics

and public health emergencies, and risks related to 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, 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

Media Relations

Rebecca Novak, rnovak@milestonepharma.com

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