[Form 4] CRESCENT BIOPHARMA, INC. Insider Trading Activity

Rhea-AI Filing Summary

Crescent Biopharma, Inc. reported new equity awards to its Chief Medical Officer, Ellie Im. On December 15, 2025, she acquired a total of 21,298 Ordinary Shares in the form of Restricted Stock Units (RSUs), shown as two grants of 16,298 and 5,000 shares. Each RSU represents a contingent right to receive one Ordinary Share, vesting in approximately equal three-month installments over four years from December 15, 2025, as long as she continues to work for the company or its subsidiaries.

She also received a stock option covering 65,190 Ordinary Shares at an exercise price of $13.21 per share. This option vests as to 1/48th of the grant on each monthly anniversary of December 15, 2025, subject to continued service, and is exercisable until December 15, 2035.

Insider Trade Summary

3 transactions reported

Mixed 3 txns

Insider Im Ellie Eunkyung

Role Chief Medical Officer

Type	Security	Shares	Price	Value
Grant/Award	Stock Option (Right to Buy)	65,190	$0.00	--
Grant/Award	Ordinary Shares	16,298	$0.00	--
Grant/Award	Ordinary Shares	5,000	$0.00	--

Holdings After Transaction: Stock Option (Right to Buy) — 65,190 shares (Direct); Ordinary Shares — 16,298 shares (Direct)

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 Ordinary Shares. The RSUs shall vest in approximately equal three-month installments through the four-year anniversary of December 15, 2025, subject to the Reporting Person remaining continuously employed by or providing services to the Issuer or its subsidiaries from December 15, 2025 through each such vesting date. This Option represents a right to purchase shares of the Issuer's Ordinary Shares and vests with respect to 1/48th of the Option on each monthly anniversary of December 15, 2025, subject to the Reporting Person remaining continuously employed by or providing services to the Issuer or its subsidiaries from December 15, 2025 through each such vesting 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^*

Im Ellie Eunkyung

(Last) (First) (Middle)

C/O CRESCENT BIOPHARMA, INC.

300 FIFTH AVENUE

(Street)

WALTHAM MA 02451

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
CRESCENT BIOPHARMA, INC. [ CBIO ]

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

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

3. Date of Earliest Transaction (Month/Day/Year)
12/15/2025

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
Ordinary Shares	12/15/2025		A		16,298	A	(1)	16,298	D
Ordinary Shares	12/15/2025		A		5,000	A	(1)	21,298	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)	$13.21	12/15/2025		A		65,190		(2)	12/15/2035	Ordinary Shares	65,190	$0	65,190	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 Ordinary Shares. The RSUs shall vest in approximately equal three-month installments through the four-year anniversary of December 15, 2025, subject to the Reporting Person remaining continuously employed by or providing services to the Issuer or its subsidiaries from December 15, 2025 through each such vesting date.

2. This Option represents a right to purchase shares of the Issuer's Ordinary Shares and vests with respect to 1/48th of the Option on each monthly anniversary of December 15, 2025, subject to the Reporting Person remaining continuously employed by or providing services to the Issuer or its subsidiaries from December 15, 2025 through each such vesting date.

Remarks:

	/s/ Barbara Bispham, as attorney-in-fact for Ellie Im	12/17/2025
	** 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).
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