Atrium Therapeutics (RNA) director Gallagher granted RSUs and 205,000-share option

Rhea-AI Filing Summary

Atrium Therapeutics, Inc. director and officer Kathleen P. Gallagher reported receiving equity awards as part of her compensation. She was granted 102,500 shares of common stock in the form of restricted stock units, with each unit representing one future share of common stock, subject to vesting.

Gallagher was also granted a stock option for 205,000 shares of common stock at an exercise price of $14.30 per share. Twenty-five percent of both the RSUs and the option vest on March 20, 2027, with the remaining portions vesting over subsequent years, contingent on her continued service. After these grants, she directly owns 131,361 shares of common stock and holds the full 205,000-share stock option.

Insider Trade Summary

2 transactions reported

Mixed 2 txns

Insider Gallagher Kathleen P.

Role See Remarks

Type	Security	Shares	Price	Value
Grant/Award	Stock Option (Right to Buy)	205,000	$0.00	--
Grant/Award	Common Stock	102,500	$0.00	--

Holdings After Transaction: Stock Option (Right to Buy) — 205,000 shares (Direct, null); Common Stock — 131,361 shares (Direct, null)

Footnotes (1)

1. Represents an award of restricted stock units ("RSUs"). Each RSU represents a contingent right to receive one share of the Issuer's common stock. Twenty-five percent (25%) of the RSUs shall vest on March 20, 2027, with the remaining RSUs vesting in three (3) substantially equal yearly installments each year thereafter, subject to the Reporting Person's continuous service to the Issuer on each such vesting date. Twenty-five percent (25%) of the shares underlying this option shall vest and become exercisable on March 20, 2027, with the remaining shares vesting in thirty-six (36) substantially equal monthly installments each month thereafter, subject to the Reporting Person's continuous service to the Issuer on each such vesting date.

Key Figures

RSU grant size: 102,500 shares Stock option grant: 205,000 shares Option exercise price: $14.30/share +3 more

6 metrics

RSU grant size 102,500 shares Restricted stock units awarded to Gallagher

Stock option grant 205,000 shares Option covering common stock granted to Gallagher

Option exercise price $14.30/share Exercise price for 205,000-share stock option

Shares owned after grant 131,361 shares Common stock directly owned following RSU award

RSU initial vesting date March 20, 2027 25% of RSUs vest on this date

Option expiration April 20, 2036 Expiration date of stock option grant

Key Terms

restricted stock units ("RSUs"), Stock Option (Right to Buy), vest, exercise price, +1 more

5 terms

restricted stock units ("RSUs") financial

"Represents an award of restricted stock units ("RSUs"). Each RSU represents a contingent right..."

Restricted stock units (RSUs) are a company promise to give an employee shares of stock (or cash equivalent) in the future, but only after certain conditions—usually staying with the company for a set time or hitting performance goals—are met. Investors watch RSUs because when they vest they increase the number of shares outstanding and can lead insiders to sell shares, affecting share price, company dilution and the true cost of employee pay.

Stock Option (Right to Buy) financial

"Stock Option (Right to Buy) with an exercise price of 14.3000 per share..."

vest financial

"Twenty-five percent (25%) of the RSUs shall vest on March 20, 2027..."

A vest is the process by which an employee earns the right to receive certain benefits or ownership interests, such as stock or retirement funds, over time. It’s similar to earning a reward gradually, ensuring that the benefit becomes fully yours only after a set period or meeting specific conditions. This makes it important for investors because it determines when they can actually claim or use those benefits.

exercise price financial

"conversion_or_exercise_price: "14.3000" for the Stock Option (Right to Buy)..."

The exercise price is the fixed amount at which you can buy or sell an asset, like a stock, when using an options contract. It matters because it helps determine whether exercising the option will be profitable or not, depending on the current market price. Think of it as the set price you agree on today to buy or sell later.

underlying security financial

"underlying_security_title: "Common Stock", underlying_security_shares: "205000.0000"..."

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^*

Gallagher Kathleen P.

(Last) (First) (Middle)

C/O ATRIUM THERAPEUTICS, INC.

10578 SCIENCE CENTER DRIVE, SUITE 125

(Street)

SAN DIEGO CALIFORNIA 92121

(City) (State) (Zip)

UNITED STATES

(Country)

2. Issuer Name and Ticker or Trading Symbol
Atrium Therapeutics, Inc. [ RNA ]

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

X	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	See Remarks

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
04/20/2026

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

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

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

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 Stock	04/20/2026		A		102,500(1)	A	$0	131,361	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
Stock Option (Right to Buy)	$14.3	04/20/2026		A		205,000		(2)	04/20/2036	Common Stock	205,000	$0	205,000	D

Explanation of Responses:

1. Represents an award of restricted stock units ("RSUs"). Each RSU represents a contingent right to receive one share of the Issuer's common stock. Twenty-five percent (25%) of the RSUs shall vest on March 20, 2027, with the remaining RSUs vesting in three (3) substantially equal yearly installments each year thereafter, subject to the Reporting Person's continuous service to the Issuer on each such vesting date.

2. Twenty-five percent (25%) of the shares underlying this option shall vest and become exercisable on March 20, 2027, with the remaining shares vesting in thirty-six (36) substantially equal monthly installments each month thereafter, subject to the Reporting Person's continuous service to the Issuer on each such vesting date.

Remarks:

Chief Executive Officer and President

	/s/ Brendan Winslow, Attorney-in-Fact	04/22/2026
	** 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.
* Form 4: SEC 1474 (03-26)

FAQ

What insider transaction did Atrium Therapeutics (RNA) report for Kathleen P. Gallagher?

Atrium Therapeutics reported that Kathleen P. Gallagher received equity compensation grants. She was awarded restricted stock units covering 102,500 shares of common stock and a stock option for 205,000 shares, both vesting over time based on continued service with the company.

How many Atrium Therapeutics (RNA) RSUs were granted to Kathleen P. Gallagher?

Kathleen P. Gallagher received 102,500 restricted stock units. Each RSU represents a contingent right to receive one share of Atrium Therapeutics common stock, subject to vesting conditions tied to her continued service with the company over several years.

What are the terms of Kathleen P. Gallagher’s stock option grant at Atrium Therapeutics (RNA)?

Gallagher received a stock option covering 205,000 shares of Atrium Therapeutics common stock at an exercise price of $14.30 per share. The option vests over time, starting March 20, 2027, contingent on her ongoing service with the company.

When do Kathleen P. Gallagher’s Atrium Therapeutics (RNA) RSUs begin vesting?

Twenty-five percent of Gallagher’s RSUs vest on March 20, 2027. The remaining RSUs vest in three substantially equal yearly installments after that date, provided she continues to serve Atrium Therapeutics on each scheduled vesting date.

How does the vesting schedule work for Kathleen P. Gallagher’s Atrium Therapeutics (RNA) stock option?

For Gallagher’s stock option, 25% of the underlying 205,000 shares vest and become exercisable on March 20, 2027. The balance vests in 36 substantially equal monthly installments thereafter, conditioned on her continued service with Atrium Therapeutics.

What is Kathleen P. Gallagher’s Atrium Therapeutics (RNA) share ownership after these grants?

Following these awards, Gallagher directly owns 131,361 shares of Atrium Therapeutics common stock. She also holds a stock option for 205,000 additional shares, which will become exercisable over time according to the specified vesting schedule.