Septerna, Inc. Common Stock (SEPN) Form 3 Septerna / Peter Kolchinsky ownership change

SEC Form 3

FORM 3

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

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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1. Name and Address of Reporting Person^*

RA CAPITAL MANAGEMENT, L.P.

(Last) (First) (Middle)

200 BERKELEY STREET, 18TH FLOOR

(Street)

BOSTON MA 02116

(City) (State) (Zip)

2. Date of Event Requiring Statement (Month/Day/Year)
10/24/2024

3. Issuer Name and Ticker or Trading Symbol
Septerna, Inc. [ SEPN ]

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

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

5. 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 Beneficially Owned
1. Title of Security (Instr. 4)	2. Amount of Securities Beneficially Owned (Instr. 4)	3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	4. Nature of Indirect Beneficial Ownership (Instr. 5)

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 4)	2. Date Exercisable and Expiration Date (Month/Day/Year)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Series B Preferred Stock	(1)	(1)	Common Stock	1,695,515	(1)	I	See Footnotes(2)(3)
Series B Preferred Stock	(1)	(1)	Common Stock	1,130,343	(1)	I	See Footnotes(2)(4)
Stock Option (Right to Buy)	(5)	09/22/2034	Common Stock	13,356	6.81	I	See Footnotes(2)(6)

1. Name and Address of Reporting Person^*

RA CAPITAL MANAGEMENT, L.P.

(Last) (First) (Middle)

200 BERKELEY STREET, 18TH FLOOR

(Street)

BOSTON MA 02116

(City) (State) (Zip)

1. Name and Address of Reporting Person^*

RA Capital Healthcare Fund LP

(Last) (First) (Middle)

200 BERKELEY STREET, 18TH FLOOR

(Street)

BOSTON MA 02116

(City) (State) (Zip)

1. Name and Address of Reporting Person^*

RA Capital Nexus Fund III, L.P.

(Last) (First) (Middle)

200 BERKELEY STREET, 18TH FLOOR

(Street)

BOSTON MA 02116

(City) (State) (Zip)

1. Name and Address of Reporting Person^*

Kolchinsky Peter

(Last) (First) (Middle)

C/O RA CAPITAL MANAGEMENT, L.P.

200 BERKELEY STREET, 18TH FLOOR

(Street)

BOSTON MA 02116

(City) (State) (Zip)

1. Name and Address of Reporting Person^*

Shah Rajeev M.

(Last) (First) (Middle)

C/O RA CAPITAL MANAGEMENT, L.P.

200 BERKELEY STREET, 18TH FLOOR

(Street)

BOSTON MA 02116

(City) (State) (Zip)

Explanation of Responses:

1. Each share of Series B Preferred Stock (the "Preferred Stock") is convertible into shares of Common Stock of the Issuer on a one-for-8.6103 basis without payment of further consideration. Upon the closing of the Issuer's initial public offering, the Preferred Stock will convert into the number of shares of Common Stock of the Issuer shown in column 3. The Preferred Stock has no expiration date.

2. RA Capital Management, L.P. (the "Adviser") is the investment manager for RA Capital Healthcare Fund, L.P. (the "Fund") and RA Capital Nexus Fund III, L.P. (the "Nexus Fund III"). The general partner of the Adviser is RA Capital Management GP, LLC (the "Adviser GP"), of which Dr. Peter Kolchinsky and Mr. Rajeev Shah are the managing members. Each of the Adviser, the Adviser GP, the Fund, the Nexus Fund III, Dr. Kolchinsky and Mr. Shah disclaims beneficial ownership of any of the reported securities, except to the extent of its or his respective pecuniary interest therein.

3. Held directly by the Fund.

4. Held directly by the Nexus Fund III.

5. 1/16th of the shares subject to such option vest and become exercisable in substantially equal quarterly installments following October 28, 2024, contingent upon the consummation of the Issuer's initial public offering, and subject to the Reporting Person's continuous service to the Issuer on each such date.

6. Jake Simson is a Partner of the Adviser who serves on the Issuer's board of directors. Under Dr. Simson's arrangement with the Adviser, Dr. Simson holds the option for the benefit of the Fund and the Nexus Fund III. Dr. Simson is obligated to turn over to the Adviser any net cash or stock received upon exercise of the option, which will offset advisory fees owed by the Fund and the Nexus Fund III to the Adviser. The Reporting Persons therefore disclaim beneficial ownership of the option and underlying common stock.

Remarks:

Dr. Jake Simson, a Partner of the Adviser, serves on the Issuer's board of directors.

	/s/ Peter Kolchinsky, Manager of RA Capital Management, L.P.	10/24/2024
	/s/ Peter Kolchinsky, Manager of RA Capital Healthcare Fund GP, LLC, the General Partner of RA Capital Healthcare Fund, L.P.	10/24/2024
	/s/ Peter Kolchinsky, Manager of RA Capital Nexus Fund III GP, LLC, the General Partner of RA Capital Nexus Fund III, L.P.	10/24/2024
	/s/ Peter Kolchinsky, individually	10/24/2024
	/s/ Rajeev Shah, individually	10/24/2024
	** Signature of Reporting Person	Date
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