SEC FORM 4

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

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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^*

CHANG JOSEPH Y

(Last)

(First)

(Middle)

C/O OPTIMER PHARMACEUTICALS, INC.

101 HUDSON STREET

(Street)

JERSEY CITY

07302

(City)

(State)

(Zip)

2. Issuer Name and Ticker or Trading Symbol
OPTIMER PHARMACEUTICALS INC [ OPTR ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

X	Director	10% Owner
	Officer (give title below)	Other (specify below)

3. Date of Earliest Transaction (Month/Day/Year)
10/24/2013

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)
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	Code	V	Amount	(A) or (D)	Price		6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
Common stock	10/24/2013		D		10,000	D	$10.75⁽¹⁾	7,500	D
Common stock	10/24/2013		D		7,500	D	$10.75⁽²⁾	0	D
Common stock	10/24/2013		D		46,154	D	$10.75⁽¹⁾	0	I	by spouse

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)
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)	Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	8. Price of Derivative Security (Instr. 5)		10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
Stock option (right to buy)	$1.08	10/24/2013		D			3,461	⁽³⁾	10/01/2014	Common stock	3,461	$11.7	0	D
Stock option (right to buy)	$1.08	10/24/2013		D			3,461	⁽³⁾	10/01/2014	Common stock	3,461	$11.7	0	D
Stock option (right to buy)	$2.17	10/24/2013		D			3,461	⁽³⁾	07/12/2016	Common stock	3,461	$10.61	0	D
Stock option (right to buy)	$2.17	10/24/2013		D			3,461	⁽³⁾	07/12/2016	Common stock	3,461	$10.61	0	D
Stock option (right to buy)	$7.1	10/24/2013		D			5,000	⁽³⁾	12/04/2017	Common stock	5,000	$5.68	0	D
Stock option (right to buy)	$10.75	10/24/2013		D			5,000	⁽³⁾	01/08/2019	Common stock	5,000	$2.03	0	D
Stock option (right to buy)	$11.85	10/24/2013		D			10,000	⁽³⁾	01/08/2020	Common stock	10,000	$0.93	0	D
Stock option (right to buy)	$9.56	10/24/2013		D			10,000	⁽³⁾	12/01/2020	Common stock	10,000	$3.22	0	D

Explanation of Responses:

1. Pursuant to the Agreement and Plan of Merger, dated as of July 30, 2013 (the "Merger Agreement"), among Optimer Pharmaceuticals, Inc. ("Optimer"), Cubist Pharmaceuticals, Inc. ("Cubist"), and PDRS Corporation, shares were converted into the right to receive per share consideration of: (i) $10.75 cash and (ii) one contingent value right issued by Cubist in accordance with the Contingent Value Rights Agreement, dated as of October 24, 2013, between Cubist and American Stock Transfer & Trust Company, LLC (together, the "Per Share Merger Consideration").

2. Pursuant to the terms of the Merger Agreement, each award was fully vested and converted into the right to receive the Per Share Merger Consideration with respect to each share of Optimer common stock subject to the award.

3. Pursuant to the terms of the Merger Agreement, each option was converted into the right to receive a cash payment equal to the excess, if any, of $12.78 (the last reported sale price of a share of Optimer common stock on The NASDAQ Global Select Market on October 23, 2013) over such option's per share exercise price.

	Joseph Y. Chang	10/28/2013
	** Signature of Reporting Person	Date
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