[Form 4] Cullinan Therapeutics, Inc. Insider Trading Activity

Rhea-AI Filing Summary

Cullinan Therapeutics (CGEM): Lynx1-affiliated reporting persons disclosed open‑market purchases of Common Stock across four days, increasing their indirect holdings. Following the most recent transaction, beneficial ownership stood at 8,797,833 shares, held indirectly through Lynx1 Master Fund LP as described in the filing.

• 10/14/2025: 15,032 shares at a weighted avg price of $7.587 (purchases ranged $7.50–$7.68).
• 10/15/2025: 51,500 shares at $7.9427 (range $7.88–$8.00).
• 10/16/2025: 150,000 shares at $8.855 (range $8.68–$9.22).
• 10/17/2025: 32,217 shares at $7.8395 (range $7.78–$7.85).

The filing lists the transactions as purchases and notes the indirect ownership structure via Lynx1 Capital Management LP and related entities.

Insights

Insider Transactions Analyst

Open-market purchases by a director via a fund increased indirect holdings; generally a favorable governance signal.

Lynx1 Master Fund LP reported open-market purchases of Common Stock of Cullinan Therapeutics, Inc. (CGEM) across four dates. The buys were: 15,032 shares on 10/14/2025 at a weighted average of $7.587 (range $7.50–$7.68), 51,500 shares on 10/15/2025 at $7.9427 (range $7.88–$8.00), 150,000 shares on 10/16/2025 at $8.855 (range $8.68–$9.22), and 32,217 shares on 10/17/2025 at $7.8395 (range $7.78–$7.85). After these, indirect beneficial ownership reported is 8,797,833 shares.

The holdings are reported as indirect through Lynx1 Master Fund LP, with Lynx1 Capital Management LP as investment manager and Weston Nichols as sole member of the GP of the investment manager. Each reporting person disclaims beneficial ownership beyond any pecuniary interest. No derivative transactions were reported. Weighted-average pricing indicates multiple executions within the stated ranges; detailed breakdowns are available upon request to the issuer or the SEC staff.

This filing signals incremental insider-aligned buying and a sizable reported indirect position. Key dependencies include the indirect nature of ownership and the disclaimers, which limit control implications. Items to watch: any subsequent Form 4 filings altering the 8,797,833-share figure, and whether future transactions maintain open-market purchase patterns through Q4 2025.

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^*

Lynx1 Capital Management LP

(Last) (First) (Middle)

D81 CALLE C

SUITE 301 PMB 1202

(Street)

DORADO PR 00646-2051

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
Cullinan Therapeutics, Inc. [ CGEM ]

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

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

3. Date of Earliest Transaction (Month/Day/Year)
10/14/2025

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

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

	Form filed by One Reporting Person
X	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, $0.0001 par value per share ("Common Stock")	10/14/2025		P		15,032	A	$7.587(1)	8,564,116	I	See footnote(2)
Common Stock	10/15/2025		P		51,500	A	$7.9427(3)	8,615,616	I	See footnote(2)
Common Stock	10/16/2025		P		150,000	A	$8.855(4)	8,765,616	I	See footnote(2)
Common Stock	10/17/2025		P		32,217	A	$7.8395(5)	8,797,833	I	See footnote(2)

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

1. Name and Address of Reporting Person^*

Lynx1 Capital Management LP

(Last) (First) (Middle)

D81 CALLE C

SUITE 301 PMB 1202

(Street)

DORADO PR 00646-2051

(City) (State) (Zip)

Relationship of Reporting Person(s) to Issuer

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

1. Name and Address of Reporting Person^*

Nichols Weston

(Last) (First) (Middle)

D81 CALLE C

SUITE 301 PMB 1202

(Street)

DORADO PR 00646-2051

(City) (State) (Zip)

Relationship of Reporting Person(s) to Issuer

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

Explanation of Responses:

1. The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $7.50 to $7.68 inclusive. The Reporting Persons undertake to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission (the "SEC"), upon request, full information regarding the number of shares purchased at each separate price within the range set forth herein.

2. The securities to which this filing relates are held directly by Lynx1 Master Fund LP to which Lynx1 Capital Management LP (the "Investment Manager") serves as investment manager. Weston Nichols ("Mr. Nichols") is the sole member of Lynx1 Capital Management GP LLC, the general partner of the Investment Manager. Each of the Investment Manager and Mr. Nichols disclaims beneficial ownership of the securities to which this filing relates for purposes of Section 16 of the Securities and Exchange Act of 1934, as amended, except to the extent of his or its pecuniary interest therein, if any.

3. The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $7.88 to $8.00 inclusive. The Reporting Persons undertake to provide to the Issuer, any security holder of the Issuer, or the staff of the SEC, upon request, full information regarding the number of shares purchased at each separate price within the range set forth herein.

4. The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $8.68 to $9.22 inclusive. The Reporting Persons undertake to provide to the Issuer, any security holder of the Issuer, or the staff of the SEC, upon request, full information regarding the number of shares purchased at each separate price within the range set forth herein.

5. The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $7.78 to $7.85 inclusive. The Reporting Persons undertake to provide to the Issuer, any security holder of the Issuer, or the staff of the SEC, upon request, full information regarding the number of shares purchased at each separate price within the range set forth herein.

	Lynx1 Capital Management LP, By: Lynx1 Capital Management GP LLC, its general partner, By: /s/ Weston Nichols, Sole Member	10/21/2025
	/s/ Weston Nichols	10/21/2025
	** 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 did CGEM insiders report on Form 4?

Reporting persons affiliated with Lynx1 disclosed open‑market purchases of Cullinan Therapeutics Common Stock over four dates in October 2025.

How many CGEM shares were held after the last transaction?

Beneficial ownership following the 10/17/2025 transaction was 8,797,833 shares (indirect).

On which dates and at what prices were shares purchased?

Purchases and weighted average prices: 10/14 at $7.587, 10/15 at $7.9427, 10/16 at $8.855, 10/17 at $7.8395.

What were the transaction price ranges for each date?

Ranges: $7.50–$7.68 (10/14), $7.88–$8.00 (10/15), $8.68–$9.22 (10/16), $7.78–$7.85 (10/17).

How is the ownership structured according to the filing?

The securities are held by Lynx1 Master Fund LP; Lynx1 Capital Management LP is the investment manager, with related disclaimers of beneficial ownership as stated.

Were these reported as purchases or sales?

They were reported as purchases (transaction code P), increasing the reported beneficial holdings after each date.