Sec Form 4/A Filing - OSTRACH MICHAEL S @ THRESHOLD PHARMACEUTICALS INC - 2006-09-26

FORM 4/A 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

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1. Name and Address of Reporting Person OSTRACH MICHAEL S 2. Issuer Name and Ticker or Trading Symbol THRESHOLD PHARMACEUTICALS INC [ THLD] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner X __ Officer (give title below) _____ Other (specify below) Chief Operating Officer (Last) (First) (Middle) C/O THRESHOLD PHARMACEUTICALS, INC., 1300 SEAPORT BOULEVARD, 5TH FLOOR 3. Date of Earliest Transaction (MM/DD/YY) 09/26/2006 (Street) REDWOOD CITY, CA94063 4. If Amendment, Date Original Filed (MM/DD/YY) 09/28/2006 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

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 Option (Right to Buy) ( 1 ) $ 2.57 ( 2 ) 09/29/2006( 2 ) A 250,000 ( 3 ) 09/13/2015 Common Stock 250,000 ( 5 ) 250,000 D Stock Option (Right to Buy) $ 12.45 09/26/2006 D 250,000 09/12/2006 09/13/2015 Common Stock 250,000 ( 5 ) 0 D Stock Option (Right to Buy) ( 1 ) $ 2.57 ( 2 ) 09/29/2006( 2 ) A 50,000 ( 4 ) 03/13/2016 Common Stock 50,000 ( 6 ) 50,000 D Stock Option (Right to Buy) $ 14.51 09/26/2006 D 50,000 02/01/2006 03/13/2016 Common Stock 50,000 ( 6 ) 0 D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other OSTRACH MICHAEL S C/O THRESHOLD PHARMACEUTICALS, INC. 1300 SEAPORT BOULEVARD, 5TH FLOOR REDWOOD CITY, CA94063 Chief Operating Officer Signatures /s/ David L. Southern, Attorney-in-fact 10/02/2006 Signature of Reporting Person Date

Explanation of Responses:

( 1 )The stock option was granted pursuant to the Threshold Pharmaceuticals, Inc. 2004 Amended and Restated Equity Incentive Plan. ( 2 )This amendment to Form 4 amends the Form 4 filed on September 28, 2006 to reflect the accurate grant date of September 29, 2006 and to reflect the accurate exercise price of $2.57. ( 3 )This option shall vest and become exercisable commencing on September 29, 2006 in equal monthly installments, with the last installment vesting on September 12, 2009. ( 4 )This option shall vest and become exercisable commencing on September 29, 2006 in equal monthly installments, with the last installment vesting on January 1, 2010. ( 5 )On September 26, 2006, the issuer canceled, pursuant to the issuer's option exchange program, an option granted to the reporting person on September 14, 2005. In exchange, the reporting person has received a replacement option on September 29, 2006, for the same number of shares, having an exercise price equal to $2.57, the closing market price of the underlying stock on the grant date. ( 6 )On September 26, 2006, the issuer canceled, pursuant to the issuer's option exchange program, an option granted to the reporting person on March 14, 2006. In exchange, the reporting person has received a replacement option on September 29, 2006, for the same number of shares, having an exercise price equal to $2.57, the closing market price of the underlying stock on the grant 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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