Sec Form 4 Filing - Beddingfield III Frederick @ Sienna Biopharmaceuticals, Inc. - 2019-08-06

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 Beddingfield III Frederick 2. Issuer Name and Ticker or Trading Symbol Sienna Biopharmaceuticals, Inc. [ SNNA] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X __ Director _____ 10% Owner X __ Officer (give title below) _____ Other (specify below) President & CEO (Last) (First) (Middle) C/O SIENNA BIOPHARMACEUTICALS, INC., 30699 RUSSELL RANCH ROAD, SUITE 140 3. Date of Earliest Transaction (MM/DD/YY) 08/06/2019 (Street) WESTLAKE VILLAGE, CA91362 4. If Amendment, Date Original Filed (MM/DD/YY) 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 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 08/06/2019 A 150,000 A 967,599 ( 2 ) D Common Stock 112,614 I See Footnote ( 3 )

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 Stock Options (Right to buy) $ 15.08 08/06/2019 D( 4 ) 190,910 ( 5 ) 06/01/2028 Common Stock 190,910 ( 4 ) 0 D Stock Options (Right to buy) $ 15 08/06/2019 D( 4 ) 42,590 ( 6 ) 07/26/2027 Common Stock 42,590 ( 4 ) 0 D Stock Options (Right to buy) $ 2.32 08/06/2019 D( 4 ) 40,968 01/01/2019 01/01/2029 Common Stock 40,968 ( 4 ) 0 D Stock Options (Right to buy) $ 2.32 08/06/2019 D( 4 ) 93,750 ( 7 ) 01/01/2029 Common Stock 93,750 ( 4 ) 0 D Stock Options (Right to buy) $ 2.32 08/06/2019 D( 4 ) 93,750 ( 8 ) 01/01/2029 Common Stock 93,750 ( 4 ) 0 D Stock Options (Right to buy) $ 0.71 08/06/2019 A( 4 ) 42,590 ( 6 ) 07/26/2027 Common Stock 42,590 ( 4 ) 42,590 D Stock Options (Right to buy) $ 0.71 08/06/2019 A( 4 ) 190,910 ( 5 ) 06/01/2028 Common Stock 190,910 ( 4 ) 190,910 D Stock Options (Right to buy) $ 0.71 08/06/2019 A( 4 ) 40,968 01/01/2019 01/01/2029 Common Stock 40,968 ( 4 ) 40,968 D Stock Options (Right to buy) $ 0.71 08/06/2019 A( 4 ) 93,750 ( 7 ) 01/01/2029 Common Stock 93,750 ( 4 ) 93,750 D Stock Options (Right to buy) $ 0.71 08/06/2019 A( 4 ) 93,750 ( 8 ) 01/01/2029 Common Stock 93,750 ( 4 ) 93,750 D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Beddingfield III Frederick C/O SIENNA BIOPHARMACEUTICALS, INC. 30699 RUSSELL RANCH ROAD, SUITE 140 WESTLAKE VILLAGE, CA91362 X President & CEO Signatures /s/ Timothy K. Andrews, attorney-in-fact for Frederick C. Beddingfield III 08/08/2019 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Award of restricted stock units ("RSUs") granted under the Issuer's 2017 Incentive Award Plan. Each RSU entitles the Reporting Person to receive one share of Issuer common stock upon vesting. The award vests as to fifty percent (50%) of the total number of RSUs on February 6, 2020, twenty-five percent (25%) of the total number of RSUs on August 6, 2020, and the remaining twenty-five percent (25%) of the total number of RSUs on February 6, 2021, in each case, subject to the Reporting Person's continued employment or service relationship with the Issuer through the applicable vesting date. ( 2 )Includes a total of 5,916 shares of the Issuer's common stock acquired pursuant to the Issuer's Employee Stock Purchase Plan. ( 3 )The shares are directly held by the Beddingfield Family Trust. ( 4 )The transaction reported herein reflect a one-time stock option repricing (the "Option Repricing") that became effective on August 6, 2019 and are being reported in this manner solely to comply with the technical reporting requirements under Section 16(a) of the Securities Exchange Act of 1934. Pursuant to the Option Repricing, the exercise price of each relevant option has been amended to reduce such exercise price to $0.71. There have been no other changes to the terms of the relevant options. ( 5 )Twenty-Five percent (25%) of the shares subject to the option vest and become exercisable on the first anniversary measured from June 1, 2018, and the remaining shares subject to the option vest and become exercisable in 36 successive, equal monthly installments thereafter, subject to the Reporting Person's continued employment or service relationship with the Issuer on each such vesting date. ( 6 )Twenty-Five percent (25%) of the share subject to the option vest and become exercisable on the first anniversary measured from July 26, 2017, and the remaining shares subject to the option vest and become exercisable in 36 successive, equal monthly installments thereafter, subject to the Reporting Person's continued employment or service relationship with the Issuer on each such vesting date. ( 7 )Twenty percent (20%) of the shares subject to the option vest and become exercisable upon satisfaction of one performance-based milestone, forty percent (40%) of the shares vest and become exercisable upon satisfaction of a second performance-based milestone, and the remaining forty percent (40%) of the shares vest and become exercisable upon satisfaction of a third performance-based milestone, subject to the Reporting Person's continued employment or service relationship with the Issuer on each such vesting date. ( 8 )Twenty-five percent (25%) of the shares subject to the option vest and become exercisable on July 1,2019, twenty-five percent (25%) of the shares vest and become exercisable on January 1, 2020, and the remaining shares vest and become exercisable in 12 successive, equal monthly installments thereafter, subject to the Reporting Person's continued employment or service relationship with the Issuer on each such vesting date.

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.