FDA approval vests Cardamyst PSUs for Milestone (MIST) Chief Commercial Officer

Rhea-AI Filing Summary

Milestone Pharmaceuticals Chief Commercial Officer Muller Lorenz reported multiple equity compensation events tied to regulatory and service milestones. On December 12, 2025, a performance stock unit award for 100,000 common shares vested after the U.S. Food and Drug Administration issued a New Drug Application Approval Letter for Cardamyst (etripamil), and a separate employee stock option for 100,000 shares with a $1.74 exercise price was granted, vesting in two halves on June 12, 2026 and December 12, 2026.

On January 26, 2026, 20,100 restricted stock units converted into common shares as part of an award that vests in four annual installments through January 26, 2029. Shares totaling 53,566 at a weighted average price of $2.32 and 11,180 at $1.93 were sold solely to cover tax liabilities from PSU and RSU vesting. After these transactions, Lorenz directly owned 205,406 common shares, 100,000 stock options, and 60,300 restricted stock units.

Positive

• FDA approval of Cardamyst (etripamil) is confirmed by the vesting trigger for 100,000 performance stock units, marking a major regulatory milestone for Milestone Pharmaceuticals.
• Equity incentives for the Chief Commercial Officer (PSUs, RSUs, and 100,000 stock options at a $1.74 exercise price) further align management compensation with Cardamyst’s approval and ongoing service.

Negative

• None.

Insights

Biopharmaceutical equity analyst

FDA approval of Cardamyst triggered significant equity vesting for Milestone’s CCO.

The filing shows that a performance stock unit award for 100,000 common shares vested when the U.S. Food and Drug Administration granted a New Drug Application Approval Letter for Cardamyst (etripamil). This ties management compensation directly to achieving a key regulatory milestone.

In addition, 100,000 employee stock options with a $1.74 exercise price were granted, vesting in two tranches on June 12, 2026 and December 12, 2026, contingent on continued service. Further RSU vesting and related sell-to-cover sales indicate routine tax-driven liquidity rather than discretionary selling.

From an incentive perspective, the combination of vested PSUs, remaining RSUs, and options concentrates Muller Lorenz’s exposure on Cardamyst’s commercialization and the company’s longer-term performance. Future company filings may provide additional detail on how FDA approval of Cardamyst influences revenue and profitability.

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

OMB Number:			3235-0287
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hours per response:			0.5

Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Muller Lorenz

(Last) (First) (Middle)

C/O MILESTONE PHARMACEUTICALS INC.

1111 DR. FREDERIK-PHILIPS BLVD, STE 420

(Street)

MONTREAL A8 H4M 2X6

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
Milestone Pharmaceuticals Inc. [ MIST ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	Chief Commercial Officer

3. Date of Earliest Transaction (Month/Day/Year)
12/12/2025

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Shares	12/12/2025		A		100,000(1)	A	(2)	250,052	D
Common Shares	12/15/2025		S(3)		53,566	D	$2.32(4)	196,486	D
Common Shares	01/26/2026		M		20,100	A	(5)	216,586	D
Common Shares	01/26/2026		S(3)		11,180	D	$1.93(4)	205,406	D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Employee Stock Option (right to buy)	$1.74	12/12/2025		A		100,000		(6)	05/06/2034	Common Shares	100,000	$0	100,000	D
Restricted Stock Units	(5)	01/26/2026		M			20,100	(7)	(7)	Common Shares	20,100	$0	60,300	D

Explanation of Responses:

1. Represents a performance stock unit ("PSU") award that vested upon the certification by the Compensation Committee of the Board of Directors of the Issuer that the U.S. Food and Drug Administration has provided a New Drug Application Approval Letter granting approval of Cardamyst (etripamil).

2. Each PSU represents a contingent right to receive one common share.

3. Represents shares sold pursuant to a sell-to-cover arrangement for the purpose of satisfying income tax liabilities incurred upon vesting of PSUs or restricted stock unit ("RSU") awards only, respectively.

4. The price reported is a weighted average price. These shares were sold in multiple transactions. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote.

5. Each RSU represents a contingent right to receive one common share.

6. 50% of the option will vest on June 12, 2026 and 50% will vest on December 12, 2026, subject to the Reporting Person continuing to provide service through each such date.

7. One-fourth (1/4th) of the shares subject to the RSU award vested or will vest on each of January 26, 2026, January 26, 2027, January 26, 2028 and January 26, 2029, subject to the Reporting Person continuing to provide service through each such date.

	/s/ Joseph Oliveto, Attorney-in-Fact	01/28/2026
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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FAQ

What insider transactions did Milestone Pharmaceuticals (MIST) report for Muller Lorenz?

The filing reports vesting of 100,000 performance stock units, grant of 100,000 stock options at a $1.74 exercise price, vesting of 20,100 restricted stock units, and related share sales to cover tax liabilities from PSU and RSU vesting events.

How is FDA approval of Cardamyst reflected in this Milestone Pharmaceuticals (MIST) Form 4?

A performance stock unit award for 100,000 shares vested after the Compensation Committee certified that the FDA issued a New Drug Application Approval Letter granting approval for Cardamyst (etripamil), directly tying the vesting condition to this regulatory milestone.

What stock option grant did Muller Lorenz receive from Milestone Pharmaceuticals (MIST)?

Muller Lorenz received an employee stock option for 100,000 common shares at a $1.74 exercise price. Half vests on June 12, 2026 and the other half on December 12, 2026, subject to continued service with the company through those dates.

Why did Muller Lorenz sell Milestone Pharmaceuticals (MIST) shares in December 2025 and January 2026?

The filing states that 53,566 shares at a weighted average of $2.32 and 11,180 shares at $1.93 were sold under sell-to-cover arrangements solely to satisfy income tax liabilities from vesting PSUs and RSUs, not as discretionary open-market sales.

How many Milestone Pharmaceuticals (MIST) shares and units does Muller Lorenz hold after these transactions?

After the reported transactions, Muller Lorenz directly beneficially owned 205,406 common shares, 100,000 employee stock options with a $1.74 exercise price, and 60,300 restricted stock units that vest in four annual installments through January 26, 2029.

What are the vesting terms for Muller Lorenz’s restricted stock units at Milestone Pharmaceuticals (MIST)?

One-fourth of the RSU award vests or will vest on each of January 26, 2026, January 26, 2027, January 26, 2028, and January 26, 2029, provided Muller Lorenz continues to provide service to Milestone Pharmaceuticals through each applicable vesting date.