Cardamyst approval triggers PSU vesting for Milestone (MIST) COO

Rhea-AI Filing Summary

Milestone Pharmaceuticals Inc. Chief Operating Officer Nelson Jeffrey Edward reported multiple equity award events tied to Cardamyst (etripamil). A 100,000-share performance stock unit award vested after FDA New Drug Application approval of Cardamyst, with each PSU delivering one common share. He also received an option for 100,000 common shares at $1.74 per share, vesting in two equal installments on June 12, 2026 and December 12, 2026, subject to continued service. On January 26, 2026, 20,100 restricted stock units converted into common shares, and 12,245 shares were sold at a weighted average price of $1.93 under a sell-to-cover arrangement to satisfy tax liabilities, following an earlier 58,007-share sell-to-cover sale at $2.32 on December 15, 2025.

Insider Trade Summary

Net Seller: 70,252 shares ($158,209)

Net Sell 6 txns

Insider Nelson Jeffrey Edward

Role Chief Operating Officer

Sold 70,252 shs ($158K)

Type	Security	Shares	Price	Value
Exercise	Restricted Stock Units	20,100	$0.00	--
Exercise	Common Shares	20,100	$0.00	--
Sale	Common Shares	12,245	$1.93	$24K
Sale	Common Shares	58,007	$2.32	$135K
Grant/Award	Employee Stock Option (right to buy)	100,000	$0.00	--
Grant/Award	Common Shares	100,000	$0.00	--

Holdings After Transaction: Restricted Stock Units — 60,300 shares (Direct); Common Shares — 62,093 shares (Direct); Employee Stock Option (right to buy) — 100,000 shares (Direct)

Footnotes (1)

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

Form 4 Insider Transactions: What Each Field Means →

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
Estimated average burden
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^*

Nelson Jeffrey Edward

(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 Operating 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)	100,000	D
Common Shares	12/15/2025		S(3)		58,007	D	$2.32(4)	41,993	D
Common Shares	01/26/2026		M		20,100	A	(5)	62,093	D
Common Shares	01/26/2026		S(3)		12,245	D	$1.93(4)	49,848	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.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.

FAQ

What insider activity did MIST COO Nelson Jeffrey Edward report?

Nelson Jeffrey Edward reported PSU vesting, option grants, RSU conversion, and tax sales. A 100,000-share PSU award vested, a 100,000-share option was granted, RSUs converted into 20,100 common shares, and shares were sold under sell-to-cover arrangements to satisfy income tax liabilities.

How is Cardamyst approval linked to the MIST COO’s PSU award?

The PSU award vested upon FDA approval of Cardamyst (etripamil). Vesting occurred after the compensation committee certified receipt of a New Drug Application Approval Letter granting Cardamyst approval, causing 100,000 performance stock units to convert into an equivalent number of common shares.

What stock options did the MIST COO receive in this Form 4?

He received an option for 100,000 common shares at $1.74 per share. The option vests 50% on June 12, 2026 and 50% on December 12, 2026, contingent on his continued service with Milestone Pharmaceuticals through each vesting date.

Why did the MIST COO sell shares on December 15, 2025 and January 26, 2026?

The sales were made under sell-to-cover tax arrangements. The filing states these transactions were executed solely to cover income tax liabilities triggered by the vesting of performance stock units or restricted stock unit awards, rather than discretionary open-market sales.

What happened to the MIST COO’s restricted stock units on January 26, 2026?

20,100 RSUs were converted into common shares on that date. Each restricted stock unit became one Milestone common share, and separate footnotes explain the broader RSU vesting schedule across four annual installments through January 26, 2029, subject to continued service.

What is the vesting schedule for the MIST COO’s RSU award at Milestone (MIST)?

The RSU award vests in four equal annual installments. One-fourth of the shares vest or will vest on each of January 26, 2026, 2027, 2028, and 2029, provided the executive continues to provide service to Milestone Pharmaceuticals through each scheduled vesting date.