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).

1. Name and Address of Reporting Person ^*

Portman David J.

(Last)

(First)

(Middle)

250 E. BROAD ST., SUITE 250

(Street)

COLUMBUS

43215

(City)

(State)

(Zip)

2. Issuer Name and Ticker or Trading Symbol
LeonaBio, Inc. [ LONA ]

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)
10/26/2026

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)
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	Code	V	Amount	(A) or (D)	Price		6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
Common Stock	10/26/2026	10/26/2026	P		3,149,470	A	$ 3,149.47	3,149,470	I	See note

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)
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)	Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	8. Price of Derivative Security (Instr. 5)		10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
Warrant ⁽¹⁾	$ 0.001	10/26/2026	10/26/2026	P			5,502,402	10/26/2026	⁽²⁾	Common Stock	5,502,402	$ 3,149.47	0	I	See note ⁽³⁾

Explanation of Responses:

1. The shares are held by Sermonix Pharmaceuticals, Inc. of which Dr. Portman is the Chief Executive Officer. This Form 4 is being filed to report Dr. Portman's voting control over such securities, but Dr. Portman's personal indirect beneficial ownership does not exceed 10% of the stock in the Issuer.

2. The Warrant does not expire.

3. The Warrant was held by Sermonix Pharmaceuticals, Inc. of which Dr. Portman is the Chief Executive Officer. The Warrant was exercised on October 26, 2026, in part, into 3,149,740 Common Shares of Issuer, and the balance of the Warrant was assigned to Perceptive Xentogeny Venture Fund II, LP as a distribution-in-kind pursuant to a plan of distribution to the Sermonix Pharmaceuticals equity holders. Following the partial exercise and the assignment of the remaining Warrant rights, Sermonix Pharmaceuticals holds 3,149,740 Common Shares of Issuer.

	David J. Portman	10/28/2026
	** Signature of Reporting Person	Date
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