Sec Form 4 Filing - Fernandes Prabhavathi @ CEMPRA, INC. - 2015-05-22

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

OMB APPROVAL OMB Number: 3235-0287 Expires: November 30, 2011 Estimated average burden hours per response... 0.5

1. Name and Address of Reporting Person Fernandes Prabhavathi 2. Issuer Name and Ticker or Trading Symbol CEMPRA, INC. [ CEMP] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X __ Director _____ 10% Owner X __ Officer (give title below) _____ Other (specify below) President and CEO (Last) (First) (Middle) 6320 QUADRANGLE DRIVE, SUITE 360 3. Date of Earliest Transaction (MM/DD/YY) 05/22/2015 (Street) CHAPEL HILL, NC27517 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 05/22/2015 M 13,123 A $ 7.62 232,412 D Common Stock 05/22/2015 M 15,266 A $ 13.1 247,678 D Common Stock 05/22/2015 M 9,000 A $ 2.09 256,678 D Common Stock 05/22/2015 S 9,000 D $ 35.721 ( 1 ) 247,678 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 (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 Employee Stock Option (Right to Buy) $ 23.51 ( 2 ) 12/31/2024 Common Stock 133,499 133,499 D Employee Stock Option (Right to Buy) $ 1.43 ( 3 ) 08/07/2016 Common Stock 12,105 0 D Employee Stock Option (Right to Buy) $ 2.47 ( 4 ) 06/03/2018 Common Stock 54,273 54,273 D Employee Stock Option (Right to Buy) $ 2.09 05/22/2015 M 9,000 ( 5 ) 08/09/2019 Common Stock 82,194 $ 0 73,194 D Employee Stock Option (Right to Buy) $ 2.09 ( 6 ) 07/28/2020 Common Stock 34,133 34,133 D Employee Stock Option (Right to Buy) $ 2.09 ( 7 ) 12/07/2020 Common Stock 40,698 40,698 D Employee Stock Option (Right to Buy) $ 7.62 05/22/2015 M 13,123 ( 8 ) 03/19/2022 Common Stock 100,000 $ 0 86,877 D Employee Stock Option (Right to Buy) $ 6.63 ( 9 ) 01/17/2023 Common Stock 150,000 150,000 D Employee Stock Option (Right to Buy) $ 6.64 ( 10 ) 03/06/2023 Common Stock 50,000 50,000 D Employee Stock Option (Right to Buy) $ 13.1 ( 11 ) 01/07/2024 Common Stock 50,000 50,000 D Employee Stock Option (Right to Buy) $ 13.1 05/22/2015 M 15,266 ( 12 ) 01/07/2024 Common Stock 125,000 $ 0 109,734 D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Fernandes Prabhavathi 6320 QUADRANGLE DRIVE SUITE 360 CHAPEL HILL, NC27517 X President and CEO Signatures /s/ Alexander M. Donaldson by Power of Attorney 05/27/2015 Signature of Reporting Person Date

Explanation of Responses:

( 1 )The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $35.60 to $35.92, inclusive. ( 2 )The option vests according to the following schedule: 1/48th of the shares vest at the end of each month over 48 months, beginning after 01/01/2015. ( 3 )The option vested immediately upon its granting on 08/08/06. ( 4 )The option vested according to the following schedule: 1/4th of the shares vest on the one-year anniversary of the 06/03/08 grant date; 1/36th of the remaining shares vest at the end of each month over the next 36 months. ( 5 )The option vests according to the following schedule: 1/4th of the shares vest on the one-year anniversary of the 08/10/09 grant date; 1/36th of the remaining shares vest at the end of each month over the next 36 months. ( 6 )The option vests according to the following schedule: 1/48th of the shares vest at the end of each month over 48 months, beginning 30 days after 04/26/10. ( 7 )The option vests according to the following schedule: 1/48th of the shares vest at the end of each month over 48 months, beginning 30 days after 12/08/10. ( 8 )The option vests in full on 03/20/13. ( 9 )The option vests according to the following schedule: 1/4th of the shares vest on the last day of each quarter after 01/01/2013. ( 10 )The option vests according to the following schedule: 1/4th of the shares vest on the last day of each quarter after 01/01/13. ( 11 )The option vests according to the following schedule: 1/24th of the shares vest monthly at the end of each month over 24 months, beginning on the third anniversary of the Vesting Commencement Date of 01/01/2014. ( 12 )The option vests according to the following schedule: 1/48th of the shares vest at the end of each month over 48 months, beginning after 01/01/2014.

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).

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.