SEC Form 4

FORM 4		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 or Section 30(h) of the Investment Company Act of 1940	OMB APPROVAL OMB Number: 3235-0287 Estimated average burden hours per response: 0.5
	Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

1. Name and Address of Reporting Person* SHEMA SUZANNE M (Last) (First) (Middle) C/O ONYX PHARMACEUTICALS, INC. 249 E. GRAND AVE. (Street) SOUTH SAN FRANCISCO CA 94080 (City) (State) (Zip)	2. Issuer Name and Ticker or Trading Symbol ONYX PHARMACEUTICALS INC [ ONXX ]	5. Relationship of Reporting Person(s) to Issuer (Check all applicable) Director 10% Owner X Officer (give title below) Other (specify below) EVP, GC and Corp. Secretary
	3. Date of Earliest Transaction (Month/Day/Year) 04/08/2013
	4. 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 Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	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	04/08/2013		M		656	A	$30.28	35,274	D
Common Stock	04/08/2013		M		1,214	A	$32.07	36,488	D
Common Stock	04/08/2013		S		1,870(1)(2)	D	$89.1927	34,618	D
Common Stock	04/08/2013		M		583	A	$37.68	35,201	D
Common Stock	04/08/2013		M		796	A	$37.68	35,997	D
Common Stock	04/08/2013		S		1,379(1)(2)	D	$89.1605	34,618	D
Common Stock	04/08/2013		M		803	A	$35.18	35,421	D
Common Stock	04/08/2013		S		803(1)(2)	D	$89.1603	34,618	D

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 (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	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 (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (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: 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 Option (Right to Buy)	$30.28	04/08/2013		M			656	(3)	03/31/2020	Common Stock	656	$0.00	7,875	D
Stock Option (Right to Buy)	$32.07	04/08/2013		M			1,214	(4)	08/31/2019	Common Stock	1,214	$0.00	18,544	D
Stock Option (Right to Buy)	$37.68	04/08/2013		M			583	(5)	03/29/2022	Common Stock	583	$0.00	21,000	D
Stock Option (Right to Buy)	$37.68	04/08/2013		M			796	(6)	03/29/2022	Common Stock	796	$0.00	28,649	D
Stock Option (Right to Buy)	$35.18	04/08/2013		M			803	(7)	03/31/2021	Common Stock	803	$0.00	19,250	D

Explanation of Responses:

1. Shares sold pursuant to a 10b5-1 plan.

2. The shares were sold at prices ranging from $89.0101 to $89.5601. The reporting person will provide upon request to the SEC, the issuer or security holder of the issuer, full information regarding the number of shares sold at each separate price.

3. 12.5% of the shares subject to the option become exercisable 6 months following the date of grant. The remaining shares become exercisable in equal monthly installments over the following 42 months for a total vesting schedule of 48 months.

4. Twenty-Five percent of the shares subject to the option vest and become exercisable one year from the date of grant and vest and beceome exercisable at a rate of 1/48th per month thereafter.

5. The shares vest monthly from the date of grant at a rate of 1/48th per month over a period of 48 months.

6. 12.5% of the shares subject to the option become exercisable 6 months following the date of grant. The remaining shares become exercisable in equal monthly installments over the following 42 months for a total vesting schedule of 48 months.

7. 12.5% of the shares subject to the option become exercisable 6 months following the date of grant. The remaining shares become exercisable in equal monthly installments over the following 42 months for a total vesting schedule of 48 months.

	/s/ Matthew Fust, Attorney-in-fact	04/10/2013
	** 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 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).
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