Sec Form 4 Filing - Mayer Lawrence David @ Celator Pharmaceuticals Inc - 2016-07-12

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

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1. Name and Address of Reporting Person Mayer Lawrence David 2. Issuer Name and Ticker or Trading Symbol Celator Pharmaceuticals Inc [ CPXX] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner X __ Officer (give title below) _____ Other (specify below) See Remarks (Last) (First) (Middle) C/O CELATOR PHARMACEUTICALS, INC., 200 PRINCETONSOUTH CORP. CENTER, STE 180 3. Date of Earliest Transaction (MM/DD/YY) 07/12/2016 (Street) EWING, NJ08628 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 07/12/2016 D 107,515 D $ 30.25 ( 1 ) 0 D Common Stock 07/12/2016 D 7,468 D $ 30.25 ( 1 ) 0 I By spouse Common Stock 07/12/2016 D 3,631 D $ 30.25 ( 1 ) 0 I By spouse's trust

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) $ 3.37 07/12/2016 D 28,217 ( 2 ) 07/10/2017 Common Stock 28,217 $ 26.88 0 D Stock Option (right to buy) $ 3.116 07/12/2016 D 200,000 ( 3 ) 06/03/2023 Common Stock 200,000 $ 27.134 0 D Stock Option (right to buy) $ 3.22 07/12/2016 D 50,000 ( 4 ) 02/18/2024 Common Stock 50,000 $ 27.03 0 D Stock Option (right to buy) $ 2.79 07/12/2016 D 80,000 ( 5 ) 02/18/2024 Common Stock 80,000 $ 27.46 0 D Stock Option (right to buy) $ 1.32 07/12/2016 D 175,000 ( 6 ) 01/27/2026 Common Stock 175,000 $ 28.93 0 D Stock Option (right to buy) $ 1.32 07/12/2016 D 35,676 ( 7 ) 01/27/2026 Common Stock 35,676 $ 28.93 0 D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Mayer Lawrence David C/O CELATOR PHARMACEUTICALS, INC. 200 PRINCETONSOUTH CORP. CENTER, STE 180 EWING, NJ08628 See Remarks Signatures /s/ Lawrence David Mayer 07/12/2016 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Disposed of pursuant to the merger under the Agreement and Plan of Merger dated as of May 27, 2016 among Jazz Pharmaceuticals plc, Plex Merger Sub, Inc. and the Issuer (the "Merger") in exchange for a cash payment, representing the $30.25 purchase price per share of Issuer common stock in the Merger. ( 2 )The option (which was vested in full), was canceled in the Merger in exchange for a cash payment, representing the difference between the exercise price per share of the option and $30.25, the purchase price per share of Issuer common stock in the Merger, multiplied by the number of shares. ( 3 )The option (which had provided for vesting as follows: (i) 50,000 options vest on June 3, 2014; and (ii) 150,000 options vest in twelve consecutive quarterly installments of 12,500 shares, each on the 3rd day of the respective month beginning September 3, 2014 and continuing through June 3, 2017) was canceled in the Merger in exchange for a cash payment, representing the difference between the exercise price per share of the option and $30.25, the purchase price per share of Issuer common stock in the Merger, multiplied by the number of shares. ( 4 )The option (which had provided for vesting as follows: (i) 12,5000 options vest on February 18, 2015; and (ii) 37,500 options vest in 12 consecutive quarterly installments of 3,125 shares, each on the 18th day of the respective month beginning May 18, 2015 and continuing through February 18, 2018) was canceled in the Merger in exchange for a cash payment, representing the difference between the exercise price per share of the option and $30.25, the purchase price per share of Issuer common stock in the Merger, multiplied by the number of shares. ( 5 )The option (which had provided for vesting as follows: (i) 20,000 options vest on February 25, 2016; and (ii) 60,000 options vest in 12 consecutive quarterly installments of 5,000 shares, each on the 25th day of the respective month beginning May 25, 2016 and continuing through November 25, 2018) was canceled in the Merger in exchange for a cash payment, representing the difference between the exercise price per share of the option and $30.25, the purchase price per share of Issuer common stock in the Merger, multiplied by the number of shares. ( 6 )The option (which had provided for vesting as follows: (i) 43,750 options vest on January 27, 2017; and (ii) 120,307 options vest in 11 consecutive quarterly installments of 10,937 shares vest on the 27th day of each respective month, beginning April 27, 2017 and continuing through October 27, 2019 and (iii) 10,943 options vest on January 27, 2020) was canceled in the Merger in exchange for a cash payment, representing the difference between the exercise price per share of the option and $30.25, the purchase price per share of Issuer common stock in the Merger, multiplied by the number of shares. ( 7 )The option (which vested on March 14, 2016, the date the Issuer announced analysis of overall survival of Study 301, its Phase 3 clinical study) was canceled in the Merger in exchange for a cash payment, representing the difference between the exercise price per share of the option and $30.25, the purchase price per share of Issuer common stock in the Merger, multiplied by the number of shares.

Remarks: President and Chief Scientific Officer

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