Exhibit 10.14

GEMPHIRE THERAPEUTICS INC.

FOURTH AMENDMENT TO NOTE PURCHASE AGREEMENT AND CONVERTIBLE PROMISSORY NOTES

THIS FOURTH AMENDMENT TO NOTE PURCHASE AGREEMENT AND CONVERTIBLE PROMISSORY NOTES (this “Fourth Amendment”) is made effective as of this 26th day of April 2016 (the “Fourth Amendment Date”), by and among GEMPHIRE THERAPEUTICS INC., a Delaware corporation (the “Company”), and the purchasers of the Company’s Convertible Promissory Notes identified on the signature page attached hereto (the “Purchasers”).

BACKGROUND

The Company and the Purchasers entered into that certain Note Purchase Agreement dated as of July 31, 2015, as amended by the First Amendment to Note Purchase Agreement and Convertible Promissory Notes dated December 10, 2015 (the “First Amendment”), the Second Amendment to Note Purchase Agreement and Convertible Promissory Notes dated March 27, 2016 (the “Second Amendment”) and the Third Amendment to Note Purchase Agreement and Convertible Promissory Notes dated April 14, 2016 (the “Third Amendment” and collectively, the “Purchase Agreement”). Pursuant to the terms and conditions of the Purchase Agreement, the Company issued those certain Convertible Promissory Notes (collectively, the “Notes”, and each a “Note”) to such Purchasers. The Company and the Purchasers now wish to amend the Purchase Agreement and the Notes as provided herein.

NOW, THEREFORE, in consideration of these premises and for other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, the Company and the Purchasers hereby agree to amend the Purchase Agreement and the Notes as follows:

TERMS AND CONDITIONS

1.                                      AMENDMENT TO SECTION 1.5 OF THE PURCHASE AGREEMENT. Section 1.5 of the Purchase Agreement is hereby deleted in its entirety and replaced with the following:

“1.5 Conversion upon Change in Control or Public Transaction. If at any time prior to the Qualified Financing, the Company’s Board of Directors approves the sale of all or substantially all of the Company’s assets or stock, or a merger, consolidation or any other business combination transaction resulting in the holders of capital stock of the Company immediately before such transaction holding less than 50% of the capital stock of the surviving entity in such transaction (a “Change in Control”) or a Public Transaction, then immediately prior to the closing of such transaction, (i) One Hundred Percent (100%) of the outstanding principal balance of, plus (ii) the accrued but unpaid interest on, each Note (collectively, the “CIC / IPO Note Value”) shall automatically convert into

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that number of fully paid and non-assessable shares of the Company’s Common Stock determined by dividing the CIC / IPO Note Value by the CIC / IPO Note Conversion Price (as defined in Section 2(c) of the Notes), rounded down to the nearest whole share.”

2.                                      AMENDMENT TO SECTION 2(B) OF THE NOTES.  Section 2(b) of each existing Note is hereby deleted and replaced with the following:

“(b)                           Conversion upon Change in Control or Public Transaction.  If at any time prior to the Qualified Financing, the Company’s Board of Directors approves a Change in Control or a Public Transaction, then immediately prior to the closing of such transaction, (i) One Hundred Percent (100%) of the outstanding principal balance of, plus (ii) the accrued but unpaid interest on, this Note (collectively, the “CIC / IPO Note Value”) shall automatically convert into that number of fully paid and non-assessable shares of the Company’s Common Stock determined by dividing the CIC / IPO Note Value by the CIC / IPO Note Conversion Price (as defined below), rounded down to the nearest whole share.”

3.                                      AMENDMENT TO SECTION 2(C) OF THE NOTES.  A new Section 2(c) is hereby added to each Note, as follows:

“(c)                            The “CIC / IPO Note Conversion Price” shall initially be $2.15; provided, however, that (i) if at any time or from time to time on or after the Fourth Amendment Date the Company effects a subdivision of the outstanding Common Stock, or effects a recapitalization, reclassification, split-up or other transaction having substantially the same effect as a subdivision of the outstanding Common Stock, the CIC / IPO Note Conversion Price in effect immediately before that subdivision shall be proportionately decreased; and (ii) if at any time or from time to time on or after the Fourth Amendment Date the Company combines the outstanding shares of Common Stock into a smaller number of shares, or effects a recapitalization, reclassification, or other transaction having substantially the same effect as a combination of the outstanding Common Stock into a smaller number of shares, the CIC / IPO Note Conversion Price in effect immediately before the combination shall be proportionately increased, in each case, with such adjustment to be effective at the close of business on the date the subdivision or combination becomes effective, and following such time all references to the CIC / IPO Note Conversion Price shall mean the CIC / IPO Note Conversion Price as so adjusted.”

4.                                      NOTICE TO TRANSFEREES.  Each Purchaser hereby covenants and agrees to provide any transferee of such Purchaser’s Note with a copy of this Fourth Amendment.

5.                                      CONSTRUCTION.  Unless otherwise defined herein, capitalized terms shall have the meanings set forth in the Purchase Agreement.  The terms of this Fourth Amendment amend and modify the Purchase Agreement and each Note, as if fully set forth in the Purchase Agreement and each Note.  If there is any conflict between the terms, conditions and obligations

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of this Fourth Amendment and the Purchase Agreement or the Notes, this Fourth Amendment’s terms, conditions and obligations shall control.  All other provisions of the Purchase Agreement and the Notes not specifically modified by this Fourth Amendment are preserved.

6.                                      COUNTERPARTS.  This Fourth Amendment may be executed in one or more counterparts, each of which shall constitute an original, and all of which together shall constitute one and the same instrument.

7.                                      FACSIMILE SIGNATURE.  This Fourth Amendment may be executed by facsimile or .pdf signature.

SIGNATURES ON THE FOLLOWING PAGE

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IN WITNESS WHEREOF, this Fourth Amendment to Note Purchase Agreement and Convertible Promissory Notes is made effective as of the date first set forth above.

SIGNATURES ON THE FOLLOWING PAGE

SIGNATURE PAGE TO FOURTH AMENDMENT TO NOTE PURCHASE AGREEMENT AND CONVERTIBLE PROMISSORY NOTES

SIGNATURE PAGE TO FOURTH AMENDMENT TO NOTE PURCHASE AGREEMENT AND CONVERTIBLE PROMISSORY NOTES

SIGNATURE PAGE TO FOURTH AMENDMENT TO NOTE PURCHASE AGREEMENT AND CONVERTIBLE PROMISSORY NOTES

SIGNATURE PAGE TO FOURTH AMENDMENT TO NOTE PURCHASE AGREEMENT AND CONVERTIBLE PROMISSORY NOTES

SIGNATURE PAGE TO FOURTH AMENDMENT TO NOTE PURCHASE AGREEMENT AND CONVERTIBLE PROMISSORY NOTES

SIGNATURE PAGE TO FOURTH AMENDMENT TO NOTE PURCHASE AGREEMENT AND CONVERTIBLE PROMISSORY NOTES

SIGNATURE PAGE TO FOURTH AMENDMENT TO NOTE PURCHASE AGREEMENT AND CONVERTIBLE PROMISSORY NOTES

SIGNATURE PAGE TO FOURTH AMENDMENT TO NOTE PURCHASE AGREEMENT AND CONVERTIBLE PROMISSORY NOTES