SCHEDULE 13G

Under the Securities Exchange Act of 1934
(Amendment No.     )*

(Name of Issuer)

(Title of Class of Securities)

(CUSIP Number)

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

* The remainder of this cover page shall be filled out for a reporting person’s initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter the disclosures provided in a prior cover page.

The information required in the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 (“Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

(1)         Venrock Healthcare Capital Partners II, L.P., VHCP Co-Investment Holdings II, LLC, Venrock Healthcare Capital Partners III, L.P., VHCP Co-Investment Holdings III, LLC, VHCP Management II, LLC, VHCP Management III, LLC, Nimish Shah and Bong Koh are members of a group for the purposes of this Schedule 13G.

(2)         Consists of 365,605 shares owned by Venrock Healthcare Capital Partners II, L.P., 148,147 shares owned by VHCP Co-Investment Holdings II, LLC, 790,552 shares owned by Venrock Healthcare Capital Partners III, L.P. and 78,986 shares owned by VHCP Co-Investment Holdings III, LLC.

(3)         This percentage is calculated based upon 14,265,411 shares of the Issuer’s common stock outstanding as of August 7, 2018, as reported in the Issuer’s Quarterly Report on Form 10-Q filed with the Securities and Exchange Commission on August 14, 2018.

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(1)         Venrock Healthcare Capital Partners II, L.P., VHCP Co-Investment Holdings II, LLC, Venrock Healthcare Capital Partners III, L.P., VHCP Co-Investment Holdings III, LLC, VHCP Management II, LLC, VHCP Management III, LLC, Nimish Shah and Bong Koh are members of a group for the purposes of this Schedule 13G.

(2)         Consists of 365,605 shares owned by Venrock Healthcare Capital Partners II, L.P., 148,147 shares owned by VHCP Co-Investment Holdings II, LLC, 790,552 shares owned by Venrock Healthcare Capital Partners III, L.P. and 78,986 shares owned by VHCP Co-Investment Holdings III, LLC.

(3)         This percentage is calculated based upon 14,265,411 shares of the Issuer’s common stock outstanding as of August 7, 2018, as reported in the Issuer’s Quarterly Report on Form 10-Q filed with the Securities and Exchange Commission on August 14, 2018.

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(1)         Venrock Healthcare Capital Partners II, L.P., VHCP Co-Investment Holdings II, LLC, Venrock Healthcare Capital Partners III, L.P., VHCP Co-Investment Holdings III, LLC, VHCP Management II, LLC, VHCP Management III, LLC, Nimish Shah and Bong Koh are members of a group for the purposes of this Schedule 13G.

(2)         Consists of 365,605 shares owned by Venrock Healthcare Capital Partners II, L.P., 148,147 shares owned by VHCP Co-Investment Holdings II, LLC, 790,552 shares owned by Venrock Healthcare Capital Partners III, L.P. and 78,986 shares owned by VHCP Co-Investment Holdings III, LLC.

(3)         This percentage is calculated based upon 14,265,411 shares of the Issuer’s common stock outstanding as of August 7, 2018, as reported in the Issuer’s Quarterly Report on Form 10-Q filed with the Securities and Exchange Commission on August 14, 2018.

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(1)         Venrock Healthcare Capital Partners II, L.P., VHCP Co-Investment Holdings II, LLC, Venrock Healthcare Capital Partners III, L.P., VHCP Co-Investment Holdings III, LLC, VHCP Management II, LLC, VHCP Management III, LLC, Nimish Shah and Bong Koh are members of a group for the purposes of this Schedule 13G.

(2)         Consists of 365,605 shares owned by Venrock Healthcare Capital Partners II, L.P., 148,147 shares owned by VHCP Co-Investment Holdings II, LLC, 790,552 shares owned by Venrock Healthcare Capital Partners III, L.P. and 78,986 shares owned by VHCP Co-Investment Holdings III, LLC.

(3)         This percentage is calculated based upon 14,265,411 shares of the Issuer’s common stock outstanding as of August 7, 2018, as reported in the Issuer’s Quarterly Report on Form 10-Q filed with the Securities and Exchange Commission on August 14, 2018.

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(1)         Venrock Healthcare Capital Partners II, L.P., VHCP Co-Investment Holdings II, LLC, Venrock Healthcare Capital Partners III, L.P., VHCP Co-Investment Holdings III, LLC, VHCP Management II, LLC, VHCP Management III, LLC, Nimish Shah and Bong Koh are members of a group for the purposes of this Schedule 13G.

(2)         Consists of 365,605 shares owned by Venrock Healthcare Capital Partners II, L.P., 148,147 shares owned by VHCP Co-Investment Holdings II, LLC, 790,552 shares owned by Venrock Healthcare Capital Partners III, L.P. and 78,986 shares owned by VHCP Co-Investment Holdings III, LLC.

(3)         This percentage is calculated based upon 14,265,411 shares of the Issuer’s common stock outstanding as of August 7, 2018, as reported in the Issuer’s Quarterly Report on Form 10-Q filed with the Securities and Exchange Commission on August 14, 2018.

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(1)         Venrock Healthcare Capital Partners II, L.P., VHCP Co-Investment Holdings II, LLC, Venrock Healthcare Capital Partners III, L.P., VHCP Co-Investment Holdings III, LLC, VHCP Management II, LLC, VHCP Management III, LLC, Nimish Shah and Bong Koh are members of a group for the purposes of this Schedule 13G.

(2)         Consists of 365,605 shares owned by Venrock Healthcare Capital Partners II, L.P., 148,147 shares owned by VHCP Co-Investment Holdings II, LLC, 790,552 shares owned by Venrock Healthcare Capital Partners III, L.P. and 78,986 shares owned by VHCP Co-Investment Holdings III, LLC.

(3)         This percentage is calculated based upon 14,265,411 shares of the Issuer’s common stock outstanding as of August 7, 2018, as reported in the Issuer’s Quarterly Report on Form 10-Q filed with the Securities and Exchange Commission on August 14, 2018.

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(1)         Venrock Healthcare Capital Partners II, L.P., VHCP Co-Investment Holdings II, LLC, Venrock Healthcare Capital Partners III, L.P., VHCP Co-Investment Holdings III, LLC, VHCP Management II, LLC, VHCP Management III, LLC, Nimish Shah and Bong Koh are members of a group for the purposes of this Schedule 13G.

(2)         Consists of 365,605 shares owned by Venrock Healthcare Capital Partners II, L.P., 148,147 shares owned by VHCP Co-Investment Holdings II, LLC, 790,552 shares owned by Venrock Healthcare Capital Partners III, L.P. and 78,986 shares owned by VHCP Co-Investment Holdings III, LLC.

(3)         This percentage is calculated based upon 14,265,411 shares of the Issuer’s common stock outstanding as of August 7, 2018, as reported in the Issuer’s Quarterly Report on Form 10-Q filed with the Securities and Exchange Commission on August 14, 2018.

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(1)         Venrock Healthcare Capital Partners II, L.P., VHCP Co-Investment Holdings II, LLC, Venrock Healthcare Capital Partners III, L.P., VHCP Co-Investment Holdings III, LLC, VHCP Management II, LLC, VHCP Management III, LLC, Nimish Shah and Bong Koh are members of a group for the purposes of this Schedule 13G.

(2)         Consists of 365,605 shares owned by Venrock Healthcare Capital Partners II, L.P., 148,147 shares owned by VHCP Co-Investment Holdings II, LLC, 790,552 shares owned by Venrock Healthcare Capital Partners III, L.P. and 78,986 shares owned by VHCP Co-Investment Holdings III, LLC.

(3)         This percentage is calculated based upon 14,265,411 shares of the Issuer’s common stock outstanding as of August 7, 2018, as reported in the Issuer’s Quarterly Report on Form 10-Q filed with the Securities and Exchange Commission on August 14, 2018.

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Introductory Note: This Schedule 13G is filed on behalf of Venrock Healthcare Capital Partners II, L.P., a limited partnership organized under the laws of the State of Delaware (“VHCP II LP”), VHCP Co-Investment Holdings II, LLC, a limited liability company organized under the laws of the State of Delaware (“VHCP Co-Investment II”), Venrock Healthcare Capital Partners III, L.P., a limited partnership organized under the laws of the State of Delaware (“VHCP III LP”), VHCP Co-Investment Holdings III, LLC, a limited liability company organized under the laws of the State of Delaware (“VHCP Co-Investment III”), VHCP Management II, LLC, a limited liability company organized under the laws of the State of Delaware (“VHCP Management II”), VHCP Management III, LLC, a limited liability company organized under the laws of the State of Delaware (“VHCP Management III” and collectively with VHCP II LP, VHCP Co-Investment II, VHCP III LP, VHCP Co-Investment III and VHCP Management II, the “Venrock Entities”), Nimish Shah (“Shah”) and Bong Koh (“Koh”) in respect of Common Stock of Gemphire Therapeutics Inc.

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(1)         These shares are owned directly as follows: 365,605 shares are owned by Venrock Healthcare Capital Partners II, L.P., 148,147 shares are owned by VHCP Co-Investment Holdings II, LLC, 790,552 shares are owned by Venrock Healthcare Capital Partners III, L.P. and 78,986 shares are owned by VHCP Co-Investment Holdings III, LLC. VHCP Management II, LLC is the general partner of Venrock Healthcare Capital Partners II, L.P. and the manager of VHCP Co-Investment Holdings II, LLC. VHCP Management III, LLC is the general partner of Venrock Healthcare Capital Partners III, L.P. and the manager of VHCP Co-Investment Holdings III, LLC. Messrs. Shah and Koh are the managing members of VHCP Management II, LLC and VHCP Management III, LLC.

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SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Dated: August 20, 2018

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EXHIBITS

A:    Joint Filing Agreement

B:           Power of Attorney for Nimish Shah

C:           Power of Attorney for Bong Koh

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EXHIBIT A

JOINT FILING AGREEMENT

In accordance with Rule 13d-1(k) under the Securities Exchange Act of 1934, as amended, the undersigned agree to the joint filing on behalf of each of them of a statement on Schedule 13G (including amendments thereto) with respect to the Common Stock of Gemphire Therapeutics Inc. and further agree that this agreement be included as an exhibit to such filing. Each party to the agreement expressly authorizes each other party to file on its behalf any and all amendments to such statement. Each party to this agreement agrees that this joint filing agreement may be signed in counterparts.

In evidence whereof, the undersigned have caused this Agreement to be executed on their behalf this 20th day of August, 2018.

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EXHIBIT B

POWER OF ATTORNEY FOR NIMISH SHAH

KNOW ALL BY THESE PRESENTS, that the undersigned hereby constitutes and appoints each of David L. Stepp, Sherman G. Souther and Lisa D. Harris signing individually, the undersigned’s true and lawful attorney-in fact and agent to:

(i)             prepare execute and file, for and on behalf of the undersigned, any and all documents and filings that are required or advisable to be made with the United States Securities and Exchange Commission, any stock exchange or similar authority, under the Securities Exchange Act of 1934, as amended (the “Exchange Act”), and the rules and regulations promulgated thereunder, including without limitation (a) any Joint Filing Agreement under Rule 13d-1(k) of the Exchange Act (or any successor provision thereunder), Schedule 13D and Schedule 13G (or any successor schedules or forms adopted under the Exchange Act ) and any amendments thereto in accordance with Section 13 of the Exchange Act and the rules thereunder, and (b) Forms 3, 4 and 5 and any amendments thereto in accordance with Section 16(a) of the Exchange Act and the rules thereunder; and

(ii)          take any other action of any nature whatsoever in connection with the foregoing which, in the opinion of such attorney-in-fact, may be of benefit, in the best interest of, or legally required by, the undersigned, it being understood that the documents executed by such attorney-in-fact on behalf of the undersigned pursuant to this Power of Attorney shall be in such form and shall contain such terms and conditions as such attorney-in-fact may approve in such attorney-in-fact’s discretion.

The undersigned hereby grants to such attorney-in-fact full power and authority to do and perform any and every act and thing whatsoever requisite, necessary, or proper to be done in the exercise of any of the rights and powers herein granted, as fully to all intents and purposes as the undersigned might or could do if personally present, with full power of substitution or revocation, hereby ratifying and confirming all that such attorney-in-fact, or such attorney-in-fact’s substitute or substitutes, shall lawfully do or cause to be done by virtue of this power of attorney and the rights and powers herein granted. The undersigned acknowledges that the foregoing attorney-in-fact, in serving in such capacity at the request of undersigned, is not assuming, nor is Venrock assuming, any of the undersigned’s responsibilities to comply with the Exchange Act, including without limitation Sections 13 and 16 of the Exchange Act.

This power of Attorney shall remain in full force and effect until the earliest to occur of (a) revocation by the undersigned in a signed writing delivered to the foregoing attorney-in-fact, or (b) until such attorney-in-fact shall no longer be employed by VR Management, LLC (or its successor).

IN WITNESS WHEREOF, the undersigned has cause this Power of Attorney to be executed as of the date set forth below.

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EXHIBIT C

POWER OF ATTORNEY FOR BONG KOH

KNOW ALL BY THESE PRESENTS, that the undersigned hereby constitutes and appoints each of David L. Stepp, Sherman G. Souther and Lisa D. Harris signing individually, the undersigned’s true and lawful attorney-in fact and agent to:

(i)             prepare execute and file, for and on behalf of the undersigned, any and all documents and filings that are required or advisable to be made with the United States Securities and Exchange Commission, any stock exchange or similar authority, under the Securities Exchange Act of 1934, as amended (the “Exchange Act”), and the rules and regulations promulgated thereunder, including without limitation (a) any Joint Filing Agreement under Rule 13d-1(k) of the Exchange Act (or any successor provision thereunder), Schedule 13D and Schedule 13G (or any successor schedules or forms adopted under the Exchange Act ) and any amendments thereto in accordance with Section 13 of the Exchange Act and the rules thereunder, and (b) Forms 3, 4 and 5 and any amendments thereto in accordance with Section 16(a) of the Exchange Act and the rules thereunder; and

(ii)          take any other action of any nature whatsoever in connection with the foregoing which, in the opinion of such attorney-in-fact, may be of benefit, in the best interest of, or legally required by, the undersigned, it being understood that the documents executed by such attorney-in-fact on behalf of the undersigned pursuant to this Power of Attorney shall be in such form and shall contain such terms and conditions as such attorney-in-fact may approve in such attorney-in-fact’s discretion.

The undersigned hereby grants to such attorney-in-fact full power and authority to do and perform any and every act and thing whatsoever requisite, necessary, or proper to be done in the exercise of any of the rights and powers herein granted, as fully to all intents and purposes as the undersigned might or could do if personally present, with full power of substitution or revocation, hereby ratifying and confirming all that such attorney-in-fact, or such attorney-in-fact’s substitute or substitutes, shall lawfully do or cause to be done by virtue of this power of attorney and the rights and powers herein granted. The undersigned acknowledges that the foregoing attorney-in-fact, in serving in such capacity at the request of undersigned, is not assuming, nor is Venrock assuming, any of the undersigned’s responsibilities to comply with the Exchange Act, including without limitation Sections 13 and 16 of the Exchange Act.

This power of Attorney shall remain in full force and effect until the earliest to occur of (a)  revocation by the undersigned in a signed writing delivered to the foregoing attorney-in-fact, or (b) until such attorney-in-fact shall no longer be employed by VR Management, LLC (or its successor).

IN WITNESS WHEREOF, the undersigned has cause this Power of Attorney to be executed as of the date set forth below.

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