Ownership Submission
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, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940
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(Print or Type Responses)
1. Name and Address of Reporting Person *
  GLAXOSMITHKLINE PLC
2. Date of Event Requiring Statement (Month/Day/Year)
09/13/2018
3. Issuer Name and Ticker or Trading Symbol
Principia Biopharma Inc. [PRNB]
(Last)
(First)
(Middle)
980 GREAT WEST ROAD
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 Original Filed(Month/Day/Year)
(Street)

BRENTFORD MIDDLESEX, X0 TW8 9GS
6. Individual or Joint/Group Filing(Check Applicable Line)
_X_ Form filed by One Reporting Person
___ Form filed by More than One Reporting Person
(City)
(State)
(Zip)
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)

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly. SEC 1473 (7-02)
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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 of Derivative Security: 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 A Preferred Stock   (1)   (1) Common Stock 1,070,771 $ (1) I See footnote (7)
Series B-1 Preferred Stock   (2)   (2) Common Stock 312,741 $ (2) I See footnote (7)
Series B-2 Preferred Stock   (3)   (3) Common Stock 260,617 $ (3) I See footnote (7)
Series B-3 Preferred Stock   (4)   (4) Common Stock 544,047 $ (4) I See footnote (7)
Series C Preferred Stock   (5)   (5) Common Stock 167,537 $ (5) I See footnote (7)
Stock Purchase Warrant (Right to Buy) 08/01/2016 12/29/2022 Common Stock 28,623 (6) $ 8.99 I See footnote (7)

Reporting Owners

Reporting Owner Name / Address Relationships
Director 10% Owner Officer Other
GLAXOSMITHKLINE PLC
980 GREAT WEST ROAD
BRENTFORD MIDDLESEX, X0 TW8 9GS
    X    

Signatures

/s/ Simon Dingemans, Chief Financial Officer GlaxoSmithKline plc 09/13/2018
**Signature of Reporting Person Date

Explanation of Responses:

* If the form is filed by more than one reporting person, see Instruction 5(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).
(1) The Series A Preferred Stock is convertible into Common Stock on a 9.0839-for-one basis into the number of shares of Common Stock shown in Column 3 at any time at the holder's election and automatically upon the closing of the Issuer's initial public offering. The shares have no expiration date.
(2) The Series B-1 Preferred Stock is convertible into Common Stock on a 9.0839-for-one basis into the number of shares of Common Stock shown in Column 3 at any time at the holder's election and automatically upon the closing of the Issuer's initial public offering. The shares have no expiration date.
(3) The Series B-2 Preferred Stock is convertible into Common Stock on a 9.0839-for-one basis into the number of shares of Common Stock shown in Column 3 at any time at the holder's election and automatically upon the closing of the Issuer's initial public offering. The shares have no expiration date.
(4) The Series B-3 Preferred Stock is convertible into Common Stock on a 9.0839-for-one basis into the number of shares of Common Stock shown in Column 3 at any time at the holder's election and automatically upon the closing of the Issuer's initial public offering. The shares have no expiration date.
(5) The Series C Preferred Stock is convertible into Common Stock on an 9.0839-for-one basis into the number of shares of Common Stock shown in Column 3 at any time at the holder's election and automatically upon the closing of the Issuer's initial public offering. The shares have no expiration date.
(6) The warrant is currently exercisable, with an expiration date of December 29, 2022, and an exercise price of $8.99 per share.
(7) The shares reported herein are held of record by S.R. One, Limited, an indirect, wholly-owned subsidiary of GlaxoSmithKline plc (the "Reporting Person").

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