SEC FORM 3 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*
Hood Shana

(Last) (First) (Middle)
3611 VALLEY CENTRE DRIVE, SUITE 500

(Street)
SAN DIEGO CA 92130

(City) (State) (Zip)
2. Date of Event Requiring Statement (Month/Day/Year)
01/19/2016
3. Issuer Name and Ticker or Trading Symbol
Mast Therapeutics, Inc. [ MSTX ]
4. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
Director 10% Owner
X Officer (give title below) Other (specify below)
General Counsel & VP
5. If Amendment, Date of Original Filed (Month/Day/Year)
6. Individual or Joint/Group Filing (Check Applicable Line)
X Form filed by One Reporting Person
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
Employee Stock Option (Right to Buy) (1) 01/04/2026 Common Stock 409,000 0.42 D
Employee Stock Option (Right to Buy) (2) 06/11/2025 Common Stock 215,800 0.5 D
Employee Stock Option (Right to Buy) (3) 01/02/2025 Common Stock 176,500 0.58 D
Employee Stock Option (Right to Buy) (4) 06/19/2024 Common Stock 93,650 0.65 D
Employee Stock Option (Right to Buy) (5) 01/02/2024 Common Stock 25,600 0.47 D
Employee Stock Option (Right to Buy) (6) 06/19/2023 Common Stock 95,500 0.5 D
Employee Stock Option (Right to Buy) (7) 01/02/2023 Common Stock 22,400 0.59 D
Employee Stock Option (Right to Buy) (8) 12/07/2021 Common Stock 37,450 0.6 D
Employee Stock Option (Right to Buy) (9) 02/01/2021 Common Stock 27,069 2.29 D
Employee Stock Option (Right to Buy) (10) 03/16/2020 Common Stock 11,250 5.91 D
Explanation of Responses:
1. This option vests and becomes exercisable in 48 substantially equal monthly installments on each monthly anniversary of January 4, 2016, subject to the reporting person's continued service with the issuer.
2. This option vests and becomes exercisable in 48 substantially equal monthly installments on each monthly anniversary of June 11, 2015, subject to the reporting person's continued service with the issuer.
3. This option vests and becomes exercisable in 48 substantially equal monthly installments on each monthly anniversary of January 2, 2015, subject to the reporting person's continued service with the issuer.
4. This option vests and becomes exercisable in 48 substantially equal monthly installments on each monthly anniversary of June 19, 2014, subject to the reporting person's continued service with the issuer.
5. This option vests and becomes exercisable in 48 substantially equal monthly installments on each monthly anniversary of January 2, 2014, subject to the reporting person's continued service with the issuer.
6. This option vests and becomes exercisable in 48 substantially equal monthly installments on each monthly anniversary of June 19, 2013, subject to the reporting person's continued service with the issuer.
7. This option vests and becomes exercisable in 48 substantially equal monthly installments on each monthly anniversary of January 2, 2013, subject to the reporting person's continued service with the issuer.
8. This option vested and became exercisable in 48 substantially equal monthly installments. The first installment vested and became exercisable on January 8, 2012 and the final installment on December 8, 2015.
9. This option vested and became exercisable as to one-fourth of the underlying shares on January 1, 2012, and thereafter in 36 substantially equal monthly installments such that it became fully vested and exercisable on January 1, 2015.
10. This option vested and became exercisable as to one-fourth of the underlying shares on February 16, 2011, and thereafter in 36 substantially equal monthly installments such that it became fully vested and exercisable on February 16, 2014.
Remarks:
/s/ Shana Hood 01/22/2016
** Signature of Reporting Person 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 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).
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.
LIMITED POWER OF ATTORNEY
FOR SECTION 16 REPORTING

	KNOW ALL PERSONS BY THESE PRESENTS, that the undersigned hereby makes,
constitutes and appoints Brian M. Culley and Brandi L. Roberts, and each of
them, as the undersigned's true and lawful attorney-in-fact (the
"Attorney-in-Fact"), with full power of substitution and resubstitution, each
with the power to act alone for the undersigned and in the undersigned's name,
place and stead, in any and all capacities to:

	1.	prepare, execute in the undersigned's name and on the undersigned's behalf,
and submit to the Securities and Exchange Commission ("SEC") a Form ID,
including amendments thereto, and any other documents necessary or appropriate
to obtain codes and passwords enabling the undersigned to make electronic
filings with the SEC of reports required or considered advisable under Section
16(a) of the Securities Exchange Act of 1934 (the "Exchange Act") or any rule or
regulation of the SEC;

	2.	prepare, execute and submit to the SEC, any national securities exchange or
securities quotation system and Mast Therapeutics, Inc. (the "Company") any and
all reports (including any amendment thereto) of the undersigned required or
considered advisable under Section 16(a) of the Exchange Act, and the rules and
regulations thereunder, with respect to the equity securities of the Company,
including Forms 3, 4 and 5; and

	3.	seek or obtain, as the undersigned's representative and on the undersigned's
behalf, information regarding transactions in the Company's equity securities
from any third party, including the Company and any brokers, dealers, employee
benefit plan administrators and trustees, and the undersigned hereby authorizes
any such third party to release any such information to the Attorney-in-Fact.

	The undersigned acknowledges that:

	1.	this Limited Power of Attorney authorizes, but does not require, the
Attorney-in-Fact to act at his or her discretion on information provided to such
Attorney-in-Fact without independent verification of such information;

	2.	any documents prepared or executed by the Attorney-in-Fact on behalf of the
undersigned pursuant to this Limited Power of Attorney will be in such form and
will contain such information as the Attorney-in-Fact, in his or her discretion,
deems necessary or desirable;

	3.	neither the Company nor the Attorney-in-Fact assumes any liability for the
undersigned's responsibility to comply with the requirements of Section 16 of
the Exchange Act, any liability of the undersigned for any failure to comply
with such requirements, or any liability of the undersigned for disgorgement of
profits under Section 16(b) of the Exchange Act; and

	4.	this Limited Power of Attorney does not relieve the undersigned from
responsibility for compliance with the undersigned's obligations under Section
16 of the Exchange Act, including, without, limitation, the reporting
requirements under Section 16(a) of the Exchange Act.

	The undersigned hereby grants to the Attorney-in-Fact full power and authority
to do and perform each and every act and thing requisite, necessary or
convenient to be done in connection with the foregoing, as fully, to all intents
and purposes, as the undersigned might or could do in person, hereby ratifying
and confirming all that the Attorney-in-Fact, or his or her substitute or
substitutes, shall lawfully do or cause to be done by authority of this Limited
Power of Attorney.

	This Limited Power of Attorney shall remain in full force and effect until the
undersigned is no longer required to file Forms 4 or 5 with respect to the
undersigned's holdings of and transactions in equity securities of the Company,
unless earlier revoked by the undersigned in a signed writing delivered to the
Attorney-in-Fact.

	This Limited Power of Attorney shall be governed and construed in accordance
the laws of the State of California without regard to conflict-of-law
principles.

	IN WITNESS WHEREOF, the undersigned has executed this Limited Power of Attorney
as of January 22, 2016.

Signature: /s/ Shana Hood

Printed Name: 	Shana Hood