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* Sofinnova Venture Partners VIII, L.P. (Last) (First) (Middle) SOFINNOVA VENTURES 3000 SAND HILL ROAD, 4-250 (Street) MENLO PARK CA 94025 (City) (State) (Zip)	2. Date of Event Requiring Statement (Month/Day/Year) 09/13/2018	3. Issuer Name and Ticker or Trading Symbol Principia Biopharma Inc. [ PRNB ]
		4. Relationship of Reporting Person(s) to Issuer (Check all applicable) 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-1 Preferred Stock	(1)	(1)	Common Stock	625,482	(1)	D(2)
Series B-2 Preferred Stock	(3)	(3)	Common Stock	521,235	(3)	D(2)
Series B-3 Preferred Stock	(4)	(4)	Common Stock	453,954	(4)	D(2)
Series C Preferred Stock	(5)	(5)	Common Stock	167,537	(5)	D(2)
Warrant to Purchase Series B-3 Preferred Stock	(6)	12/29/2022	Series B-3 Preferred Stock(4)	20,938	8.9931	D(2)

1. Name and Address of Reporting Person* Sofinnova Venture Partners VIII, L.P. (Last) (First) (Middle) SOFINNOVA VENTURES 3000 SAND HILL ROAD, 4-250 (Street) MENLO PARK CA 94025 (City) (State) (Zip)

1. Name and Address of Reporting Person* Sofinnova Management VIII, L.L.C. (Last) (First) (Middle) SOFINNOVA VENTURES 3000 SAND HILL ROAD, 4-250 (Street) MENLO PARK CA 94025 (City) (State) (Zip)

1. Name and Address of Reporting Person* HEALY JAMES (Last) (First) (Middle) SOFINNOVA VENTURES 3000 SAND HILL ROAD, 4-250 (Street) MENLO PARK CA 94025 (City) (State) (Zip)

1. Name and Address of Reporting Person* POWELL MICHAEL (Last) (First) (Middle) SOFINNOVA VENTURES 3000 SAND HILL ROAD, 4-250 (Street) MENLO PARK CA 94025 (City) (State) (Zip)

1. Name and Address of Reporting Person* Mehra Anand (Last) (First) (Middle) SOFINNOVA VENTURES 3000 SAND HILL ROAD, 4-250 (Street) MENLO PARK CA 94025 (City) (State) (Zip)

Explanation of Responses:

1. Each share of the Series B-1 Preferred Stock is convertible, at any time, at the holder's election, into 1 share of the Issuer's common stock. In addition, effective immediately prior to the closing of the Issuer's initial public offering of its common stock, each share of Series B-1 Preferred Stock will automatically convert into 1 share of the Issuer's common stock. The Series B-1 Preferred Stock has no expiration date.

2. The shares are held of record by Sofinnova Venture Partners VIII, L.P. ("SVP VIII"). Sofinnova Management VIII, L.L.C. ("SM VIII") is the general partner of SVP VIII. The individual managing members of SM VIII are Michael Powell, James Healy and Anand Mehra, and they may be deemed to share voting and dispositive power over the shares held by SVP VIII. Such persons and entities disclaim beneficial ownership over the shares held by SVP VIII except to the extent of any pecuniary interest therein.

3. Each share of the Series B-2 Preferred Stock is convertible, at any time, at the holder's election, into 1 share of the Issuer's common stock. In addition, effective immediately prior to the closing of the Issuer's initial public offering of its common stock, each share of Series B-2 Preferred Stock will automatically convert into 1 share of the Issuer's common stock. The Series B-2 Preferred Stock has no expiration date.

4. Each share of the Series B-3 Preferred Stock is convertible, at any time, at the holder's election, into 1 share of the Issuer's common stock. In addition, effective immediately prior to the closing of the Issuer's initial public offering of its common stock, each share of Series B-3 Preferred Stock will automatically convert into 1 share of the Issuer's common stock. The Series B-3 Preferred Stock has no expiration date.

5. Each share of the Series C Preferred Stock is convertible, at any time, at the holder's election, into 1 share of the Issuer's common stock. In addition, effective immediately prior to the closing of the Issuer's initial public offering of its common stock, each share of Series C Preferred Stock will automatically convert into 1 share of the Issuer's common stock. The Series C Preferred Stock has no expiration date.

6. This warrant is exercisable at any time.

Remarks:

	/s/ Nathalie Auber, Attorney-in-Fact for Sofinnova Venture Partners VIII, L.P.	09/13/2018
	/s/ Nathalie Auber, Attorney-in-Fact for Sofinnova Management VIII, L.L.C.	09/13/2018
	/s/ Nathalie Auber, Attorney-in-Fact for James Healy	09/13/2018
	/s/ Nathalie Auber, Attorney-in-Fact for Michael Powell	09/13/2018
	/s/ Nathalie Auber, Attorney-in-Fact for Anand Mehra	09/13/2018
	** Signature of Reporting Person	Date
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