[Form 4] SELLAS Life Sciences Group, Inc. Insider Trading Activity

Rhea-AI Filing Summary

SELLAS Life Sciences Group, Inc. director reports open-market stock purchase. Director Katherine Bach Kalin bought 63,400 shares of SELLAS common stock on 11/19/2025 in an open-market transaction coded as a purchase. The filing shows a weighted average purchase price of $1.59 per share, with individual trades executed between $1.555 and $1.625 per share. Following this transaction, she beneficially owns 104,400 shares of SELLAS common stock in direct ownership.

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

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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^*

Kalin Katherine Bach

(Last) (First) (Middle)

C/O SELLAS LIFE SCIENCES GROUP, INC., 7

TIMES SQUARE, SUITE 2503

(Street)

NEW YORK NY 10036

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
SELLAS Life Sciences Group, Inc. [ SLS ]

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

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

3. Date of Earliest Transaction (Month/Day/Year)
11/19/2025

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 Stock	11/19/2025		P		63,400	A	$1.59(1)	104,400	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

Explanation of Responses:

1. The price reflects the weighted average purchase price of the shares of common stock purchased. These shares of common stock were purchased in multiple transactions at prices ranging from $1.555 to $1.625 per share. Ms. Kalin undertakes to provide, upon request by the staff of the Securities and Exchange Commission, the Issuer or any security holder of the Issuer, full information regarding the number of shares of common stock purchased at each price.

	/s/ Kostantinos Skordalos, Power of Attorney For: Katherine Bach Kalin	11/21/2025
	** 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 transaction did SELLAS Life Sciences Group (SLS) report?

A director of SELLAS Life Sciences Group, Inc., Katherine Bach Kalin, reported purchasing 63,400 shares of the company’s common stock on 11/19/2025 in an open-market transaction.

At what price did the SLS director buy the 63,400 shares?

The shares were bought at a weighted average price of $1.59 per share, with multiple trades executed at prices ranging from $1.555 to $1.625 per share.

How many SELLAS (SLS) shares does the director own after this transaction?

After the reported purchase, Katherine Bach Kalin beneficially owns 104,400 shares of SELLAS Life Sciences Group common stock in direct ownership.

What type of SEC form was filed for this SELLAS (SLS) insider trade?

The transaction was disclosed on an SEC Form 4, which reports changes in the beneficial ownership of a company’s equity securities by its directors, officers, and certain shareholders.

What is the relationship of the reporting person to SELLAS Life Sciences Group (SLS)?

The reporting person, Katherine Bach Kalin, is listed as a director of SELLAS Life Sciences Group, Inc. on the Form 4.

Was this SELLAS (SLS) insider trade executed as a purchase or a sale?

The Form 4 shows the transaction code P, indicating an open-market or private purchase of SELLAS common stock.