Sec Form 4 Filing - New Leaf Ventures II, L.P. @ Principia Biopharma Inc. - 2019-08-13

FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

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, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL OMB Number: 3235-0287 Expires: November 30, 2011 Estimated average burden hours per response... 0.5

1. Name and Address of Reporting Person New Leaf Ventures II, L.P. 2. Issuer Name and Ticker or Trading Symbol Principia Biopharma Inc. [ PRNB] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director X __ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) C/O NEW LEAF VENTURES, 420 LEXINGTON AVENUE, SUITE 408 3. Date of Earliest Transaction (MM/DD/YY) 08/13/2019 (Street) NEW YORK, NY10170 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) _____ Form filed by One Reporting Person __ X __ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 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 Common Stock 08/13/2019 S 250,009 D $ 35 1,938,167 I See footnote ( 1 ) ( 2 ) Common Stock 08/13/2019 S 49,991 D $ 35 387,546 I See footnote ( 3 ) ( 4 )

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 (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 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 (MM/DD/YY) 7. Title and Amount of Underlying Securities (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 of Derivative Security: 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

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other New Leaf Ventures II, L.P. C/O NEW LEAF VENTURES 420 LEXINGTON AVENUE, SUITE 408 NEW YORK, NY10170 X New Leaf Venture Associates II, L.P. C/O NEW LEAF VENTURES 420 LEXINGTON AVENUE, SUITE 408 NEW YORK, NY10170 X New Leaf Venture Management II, L.L.C. C/O NEW LEAF VENTURES 420 LEXINGTON AVENUE, SUITE 408 NEW YORK, NY10170 X New Leaf Biopharma Opportunities II, L.P. C/O NEW LEAF VENTURES 420 LEXINGTON AVENUE, SUITE 408 NEW YORK, NY10170 X New Leaf BPO Associates II, L.P. C/O NEW LEAF VENTURES 420 LEXINGTON AVENUE, SUITE 408 NEW YORK, NY10170 X New Leaf BPO Management II, L.L.C C/O NEW LEAF VENTURES 420 LEXINGTON AVENUE, SUITE 408 NEW YORK, NY10170 X Signatures New Leaf Ventures II, L.P., By: New Leaf Venture Associates II, L.P., its general partner, By: New Leaf Venture Management II, L.L.C., its general partner, By: /s/ Craig Slutzkin, Chief Financial Officer 08/15/2019 Signature of Reporting Person Date New Leaf Venture Associates II, L.P., By: New Leaf Venture Management II, L.L.C., its general partner, by /s/ Craig Slutzkin, Chief Financial Officer 08/15/2019 Signature of Reporting Person Date New Leaf Venture Management II, L.L.C., By: /s/ Craig Slutzkin, Chief Financial Officer 08/15/2019 Signature of Reporting Person Date New Leaf Biopharma Opportunities II, L.P., By: New Leaf BPO Associates II, L.P., its general partner, By: New Leaf BPO Management II, L.L.C., its general partner, By: /s/ Craig Slutzkin, Chief Financial Officer 08/15/2019 Signature of Reporting Person Date New Leaf BPO Associates II, L.P., By: New Leaf BPO Management II, L.L.C., its general partner, By: /s/ Craig Slutzkin, Chief Financial Officer 08/15/2019 Signature of Reporting Person Date New Leaf BPO Management II, L.L.C., By: /s/ Craig Slutzkin, Chief Financial Officer 08/15/2019 Signature of Reporting Person Date

Explanation of Responses:

( 1 )These shares are held directly by New Leaf Ventures II, L.P. ("NLV-II"). The general partner of NLV-II is New Leaf Venture Associates II, L.P. ("NLVA-II"). The general partner of NLVA-II is New Leaf Venture Management II, L.L.C. ("Management-II"). Each of NLVA-II and Management-II disclaim beneficial ownership of these securities and this report shall not be deemed an admission that NLVA-II or Management-II are beneficial owners of such securities for purposes of Section 16 or any other purpose, except to the extent of their respective pecuniary interests therein. Each of Ronald M. Hunt and Vijay K. Lathi, the managers of Management-II (each, a "NLV-II Manager" and collectively, the "NLV-II Managers"), New Leaf Venture Partners, L.L.C. (together with its affiliates, "New Leaf Ventures"), may each, by virtue of their respective affiliations with and/or interests in New Leaf Ventures, be deemed to have shared voting and investment power with respect to these securities. ( 2 )Each of the NLV-II Managers disclaims beneficial ownership of these securities and this report shall not be deemed an admission that any of them is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of their respective pecuniary interests therein. ( 3 )These shares are held directly by New Leaf Ventures Biopharma Opportunities II, L.P. ("BPO-II"). The general partner of BPO-II is New Leaf BPO Associates II, L.P. ("NLBA-II"). The general partner of NLBA-II is New Leaf BPO Management II, L.L.C. ("BPO Management-II"). Each of NLBA-II and BPO Management-II disclaim beneficial ownership of these securities and this report shall not be deemed an admission that NLBA-II or BPO Management-II are beneficial owners of such securities for purposes of Section 16 or any other purpose, except to the extent of their respective pecuniary interests therein. Each of Ronald M. Hunt, Vijay K. Lathi and Isaac J. Manke, the managers of BPO Management-II (each, a "BPO-II Manager" and collectively, the "BPO-II Managers"), each, by virtue of their respective affiliations with and/or interests in New Leaf Ventures, be deemed to have shared voting and investment power with respect to these securities. ( 4 )Each of the BPO-II Managers disclaims beneficial ownership of these securities and this report shall not be deemed an admission that any of them is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of their respective pecuniary interests therein.

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).

Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.