QUESTIONS AND ANSWERS ABOUT THE MERGER

        Except where specifically noted, the following information and all other information contained in this proxy statement/prospectus/information statement gives effect to NeuroBo's 10,000-for-1 split of its common stock and preferred stock, which was effective on August 13, 2019, but does not give effect to the proposed reverse stock split described in the section entitled "Matters Being Submitted to a Vote of Gemphire Stockholders—Proposal No. 2: Approval of an Amendment to the Gemphire Certificate of Incorporation Effecting the Gemphire Reverse Stock Split" in this proxy statement/prospectus/information statement (the "Gemphire Reverse Stock Split").

        The following section provides answers to frequently asked questions about the merger. This section, however, provides only summary information. For a more complete response to these questions and for additional information, please refer to the cross-referenced sections.

Q:

What is the merger?

A:

Gemphire, Merger Sub and NeuroBo have entered into the Merger Agreement, which contains the terms and conditions of the proposed business combination of Gemphire and NeuroBo. Under the Merger Agreement, Merger Sub will merge with and into NeuroBo, with NeuroBo surviving as a wholly owned subsidiary of Gemphire (the "merger").

At the effective time of the merger (the "Effective Time"), each share of NeuroBo common stock, $0.0001 par value per share ("NeuroBo common stock") outstanding immediately prior to the Effective Time (excluding certain shares to be canceled pursuant to the Merger Agreement and shares held by holders of NeuroBo common stock who have exercised and perfected appraisal rights or dissenters' rights as more fully described in the section entitled "The Merger—Appraisal Rights and Dissenters' Rights" in this proxy statement/prospectus/information statement) will be converted into the right to receive shares of Gemphire's common stock, $0.001 par value per share ("Gemphire common stock") at a ratio (the "Exchange Ratio") currently estimated to be 26.9430 shares of Gemphire common stock for each share of NeuroBo common stock. The Exchange Ratio is subject to change to account, among other things, for Gemphire's net cash at the Effective Time (the "Parent Cash Amount"), to the extent such amount is negative, or for the aggregate gross proceeds received by NeuroBo as of immediately prior to the closing of the merger (the "Closing") in its Pre-Closing Financing above the minimum required amount and up to and including $50 million. See the section entitled "—What is the Pre-Closing Financing?" below for additional information about the Pre-Closing Financing.

Because the Parent Cash Amount will not be determined until the Closing, and because, among other things, the number of shares of Gemphire common stock issuable to holders of NeuroBo common stock ("NeuroBo Stockholders") is determined based on the Parent Cash Amount and the capitalization of NeuroBo and Gemphire at the Effective Time, holders of Gemphire common stock ("Gemphire Stockholders") cannot be certain of the exact number of shares that will be issued to NeuroBo Stockholders when Gemphire Stockholders vote on the proposals at the 2019 annual meeting of Gemphire Stockholders (the "Gemphire annual meeting"). The Exchange Ratio referenced above is an estimate only and the final Exchange Ratio will be determined pursuant to a formula described in more detail in the Merger Agreement and in this proxy statement/prospectus/information statement.

As of the date of the execution of the Merger Agreement, it was estimated that as a result of the merger and based solely on the sample Exchange Ratio of 26.9430 set forth above, which is subject to adjustment, current NeuroBo Stockholders and holders of options to purchase shares of NeuroBo common stock (each a "NeuroBo Option," each holder of a NeuroBo Option a "NeuroBo Optionholder" and, collectively with the NeuroBo Stockholders, "NeuroBo Securityholders") would own, or hold rights to acquire, in the aggregate approximately 95.94% of

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the fully diluted shares of the combined company (excluding out-of-the-money Gemphire Options canceled at the Effective Time pursuant to the Merger Agreement (the "Fully Diluted Closing Gemphire Common Stock") and current Gemphire Stockholders, and holders of shares of Gemphire common stock received upon the automatic exercise, pursuant to the Merger Agreement, of any unexpired and unexercised option to purchase Gemphire common stock (each a "Gemphire Option," each holder of a Gemphire Option a "Gemphire Optionholder") having an exercise price per share less than the volume weighted average closing trading price of a share of Gemphire common stock on Nasdaq for the five consecutive trading days ending five trading days immediately prior to the date upon which the merger becomes effective (the "Gemphire Closing Price"), holders of warrants to purchase Gemphire common stock (each a "Gemphire Warrant," each holder of a Gemphire Warrant a "Gemphire Warrantholders", and collectively with the Gemphire Stockholders and Gemphire Optionholders, "Gemphire Securityholders) would own, or hold rights to acquire, in the aggregate approximately 4.06% of the Fully Diluted Gemphire Closing Common Stock, in each case, following the Effective Time and assuming a Parent Cash Amount of negative $3 million and Pre-Closing Financing for gross proceeds of $24.24 million. After the consummation of the merger, and assuming Gemphire Stockholders approve Proposal No. 3, Gemphire will change its corporate name to "NeuroBo Pharmaceuticals, Inc." as required by the Merger Agreement (the "Gemphire Name Change").

Q:

What will happen to Gemphire if, for any reason, the merger does not close?

A:

If, for any reason, the merger does not close, the Gemphire board of directors (the "Gemphire Board") may elect to dissolve and liquidate its assets. If Gemphire were able to secure additional capital to provide it with necessary financial resources, it may alternatively attempt to pursue another strategic transaction like the merger, sell or otherwise dispose of its assets or continue to operate its business. Gemphire expects that it would be difficult to secure financing in a timely manner, on favorable terms or at all. If Gemphire decides to dissolve and liquidate its assets, Gemphire would be required to pay all of its debts and contractual obligations, and to set aside certain reserves for potential future claims, and there can be no assurances as to the amount or timing of available cash left, if any, to distribute to stockholders after paying the debts and other obligations of Gemphire and setting aside funds for reserves.

Q:

Why are the two companies proposing to merge?

A:

NeuroBo and Gemphire believe that the merger will result in a clinical-stage biotechnology company focused on novel, disease-modifying therapies for neurodegenerative diseases. For a discussion of Gemphire's and NeuroBo's reasons for the merger, please see the section entitled "The Merger—Gemphire Reasons for the Merger" and "The Merger—NeuroBo Reasons for the Merger" in this proxy statement/prospectus/information statement.

Q:

Why am I receiving this proxy statement/prospectus/information statement?

A:

You are receiving this proxy statement/prospectus/information statement because you have been identified as a Gemphire Stockholder or a NeuroBo Stockholder as of the applicable record date, and you are entitled, as applicable, to (i) notice of, and to vote at, the Gemphire annual meeting or (ii) sign and return the NeuroBo written consent. This document serves as:

•

a proxy statement of Gemphire used to solicit proxies for the Gemphire annual meeting;

•

a prospectus of Gemphire used to offer shares of Gemphire common stock in exchange for shares of NeuroBo common stock in the merger and issuable upon exercise Neurobo Options; and

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•

an information statement of NeuroBo used to solicit the written consent of NeuroBo Stockholders for the adoption of the Merger Agreement and the approval of the merger and related transactions.

Q:

What is required to consummate the merger?

A:

To consummate the merger, Gemphire Stockholders must approve the issuance of Gemphire common stock to NeuroBo Stockholders pursuant to the Merger Agreement and the change of control of Gemphire resulting from the merger under Nasdaq rules (Proposal No. 1) and the Gemphire Reverse Stock Split (Proposal No. 2) and NeuroBo Stockholders must adopt the Merger Agreement, thereby approving the merger and the related transactions, including the Convertible Note Conversion.

The approval of the Gemphire Reverse Stock Split (Proposal No. 2) is required in order to allow the issuance of the shares of Gemphire common stock pursuant to the Merger Agreement and to avoid a delisting of Gemphire common stock from the Nasdaq Capital Market. Consequently, if the requisite Gemphire Stockholders approve Proposal No. 1 but do not approve Proposal No. 2, the merger will not be consummated.

The adoption of the Merger Agreement and the approval of the merger and related transactions by the NeuroBo Stockholders requires the affirmative vote (or written consent) of the holders of a majority of the shares of NeuroBo common stock and NeuroBo preferred stock, on an as-converted to NeuroBo common stock basis, each outstanding on the record date and entitled to vote thereon, the holders of at least two-thirds of the outstanding shares of NeuroBo preferred stock, together as a single class, on an as-converted to NeuroBo common stock basis, and, with respect to the Convertible Note Conversion only, the holders at least a majority of the outstanding shares of NeuroBo's Series A Preferred Stock.

As of August 6, 2019, certain NeuroBo Stockholders who in the aggregate own approximately 90% of the outstanding shares of NeuroBo capital stock on an as converted to common stock basis and certain Gemphire Stockholders who in the aggregate own approximately 26% of the outstanding shares of Gemphire common stock are parties to voting agreements with Gemphire and NeuroBo, whereby such stockholders have agreed to vote their shares in favor of the adoption or approval, as applicable, of the Merger Agreement and the transactions contemplated therein or the issuance of Gemphire common stock to NeuroBo Stockholders pursuant to the Merger Agreement, subject to the terms of the voting agreements. In addition, following the registration statement on Form S-4, of which this proxy statement/prospectus/information statement is a part, being declared effective by the U.S. Securities and Exchange Commission (the "SEC") and pursuant to the conditions of the Merger Agreement and the voting agreements, NeuroBo Stockholders who are party to the voting agreements will each execute written consents approving the merger and related transactions. Therefore, holders of a sufficient number of shares of NeuroBo capital stock required to adopt the Merger Agreement, thereby approving the merger, have agreed to adopt the Merger Agreement via written consent. NeuroBo Stockholders, including those who are parties to voting agreements, are being requested to execute written consents providing such approvals.

For a more complete description of the closing conditions under the Merger Agreement, please see the section entitled "The Merger Agreement—Conditions to the Completion of the Merger" in this proxy statement/prospectus/information statement.

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Q:

What proposals are to be voted on at the Gemphire annual meeting, other than the proposals required in connection with the merger?

A:

At the Gemphire annual meeting, the Gemphire Stockholders will also be asked to consider the following proposals, along with any other business that may properly come before the Gemphire annual meeting or any adjournment or postponement thereof:

•

Proposal No. 3 to approve an amendment to the certificate of incorporation of Gemphire changing the Gemphire corporate name to "NeuroBo Pharmaceuticals, Inc." in the form attached as Annex C;

•

Proposal No. 4 to approve the Gemphire 2019 Equity Incentive Plan (the "Gemphire 2019 Plan"), a copy of which is attached as Annex D;

•

Proposal No. 5 to elect two nominees for Class III directors to hold office until the 2022 annual meeting of stockholders and until the election and qualification of his successor, or his earlier death, resignation or removal (provided that, if the merger is completed, the Gemphire Board will be reconstituted as provided in the Merger Agreement);

•

Proposal No. 6 to ratify the appointment of Ernst & Young LLP as Gemphire's independent registered public accounting firm for the fiscal year ending December 31, 2019 (provided, however, that it is likely that the combined company may decide to engage a new independent registered public accounting firm immediately or shortly after the merger is completed); and

•

Proposal No. 7 to approve an adjournment of the Gemphire annual meeting, if necessary, to solicit additional proxies if there are not sufficient votes in favor of Proposal Nos. 1, 2, 3 or 4.

Gemphire Stockholders should understand that if the merger is completed, the effect of the approval of Proposal Nos. 5 and 6 will be limited since the composition of the Gemphire Board will be changed upon completion of the merger in accordance with the Merger Agreement and the combined organization may decide to engage a new independent registered public accounting firm immediately or shortly after completion of the merger.

Q:

What stockholder votes are required to approve the proposals required in connection with the merger at the Gemphire annual meeting?

Approval of Proposal No. 1 requires the affirmative vote of the holders of a majority of the shares of Gemphire common stock present in person or represented by proxy at the Gemphire annual meeting and entitled to vote on the matter. Approval of Proposal No. 2 requires the affirmative vote of holders of a majority of Gemphire common stock outstanding on the record date,                 , 2019, for the Gemphire annual meeting (the "Record Date") and entitled to vote on the matter.

Votes will be counted by the inspector of election appointed for the Gemphire annual meeting, who will separately count "FOR" and "AGAINST" votes, abstentions and broker non-votes. Abstentions will be counted towards the vote total and will have the same effect as "AGAINST" votes for Proposal Nos. 1, 2, 3, 4, 6, and 7. Proposal Nos. 2, 3, 6, and 7 are matters on which Gemphire expects brokers, banks or other nominees to have authority and, therefore, broker non-votes are not expected with respect to these proposals. Broker non-votes will have no effect on the outcome of Proposal Nos. 1, 4, and 5.

Q:

What will NeuroBo Securityholders receive in the merger?

A:

Gemphire and NeuroBo currently estimate, assuming for this purpose a closing date of September 30, 2019, that (i) the Parent Cash Amount will be negative $3.0 million as of Closing, (ii) the Pre-Closing Financing amount will be approximately $24.24 million, (iii) outstanding shares

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of Gemphire common stock as of the Closing will be equal to 14,872,411 (on a pre-Gemphire Reverse Stock Split basis) and (iv) outstanding shares of NeuroBo common stock and NeuroBo Options as of the Closing (giving effect to the Preferred Stock Conversion and Convertible Note Conversion) will be equal to 13,943,767. Accordingly, it is currently estimated that the Exchange Ratio at Closing will be approximately 26.9430 and, based solely on such Exchange Ratio, at Closing: NeuroBo Securityholders immediately prior to the merger will own, or hold rights to acquire, in the aggregate approximately 95.94% of the Fully Diluted Closing Gemphire Common Stock and the Gemphire Securityholders immediately prior to the merger (excluding out-of-the-money Gemphire Options cancelled at the Effective Time pursuant to the Merger Agreement) will own, or hold rights to acquire, in the aggregate approximately 4.06% of the Fully Diluted Closing Gemphire Common Stock.

Following the Effective Time, NeuroBo Optionholders will have their NeuroBo Options converted into options to purchase shares of Gemphire common stock, with the number of shares of Gemphire common stock subject to each such option and the exercise price being appropriately adjusted to reflect the Exchange Ratio.

The Exchange Ratio is calculated using a formula intended to allocate a percentage of the combined organization to existing NeuroBo Securityholders, and is subject to change as set forth in the Merger Agreement and as described herein (and as a result, Gemphire Securityholders and NeuroBo Securityholders could own more or less of the combined organization than currently anticipated).

Prior to the Effective Time, the outstanding shares of NeuroBo preferred stock and the outstanding NeuroBo convertible notes will be converted into NeuroBo common stock.

For a more complete description of what NeuroBo Securityholders will receive in the merger, please see the sections entitled "The Merger—Merger Consideration and Exchange Ratio" in this proxy statement/prospectus/information statement.

Q:

What will Gemphire Stockholders, Gemphire Optionholders and Gemphire Warrant holders receive in the merger?

A:

At the Effective Time, Gemphire Stockholders will continue to own and hold their existing shares of Gemphire common stock.

Each outstanding and unexercised Gemphire Option having an exercise price per share less than the Gemphire Closing Price will be automatically exercised in full and, in exchange therefor, each former holder of any such automatically exercised Gemphire Option will be entitled to receive a number of shares of Gemphire common stock calculated by dividing (a) the product of (i) the total number of shares of Gemphire common stock previously subject to such Gemphire Option, and (ii) the excess of the Gemphire Closing Price over the exercise price per share of the Gemphire common stock previously subject to such Gemphire Option by (b) the Gemphire Closing Price. Each outstanding and unexercised Gemphire Option that has an exercise price equal to or greater than the Gemphire Closing Price will be terminated and cease to exist for no consideration.

The terms governing Gemphire Warrants will remain in full force and effect following the Closing of the merger.

In addition, Gemphire Stockholders as of immediately prior to the Effective Time will receive one contingent value right ("CVR") for each share of Gemphire common stock held of record as of immediately prior to the Effective Time. Each CVR will represent the right to receive certain cash payments in the event rights to Gemphire's product candidate gemcabene are sold or licensed during a certain period. In particular, CVR holders will be entitled to, in the aggregate, 80% of the Gross Consideration (as defined in the CVR Agreement, as defined below, which contemplates

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the post-merger combined company's prior retention of an aggregate of $500,000) less other Permitted Deductions (as defined in the CVR Agreement) received during the 15-year period after the Closing (the "CVR Term") from the grant, sale or transfer of rights to gemcabene (other than a grant, sale or transfer of rights involving a sale or disposition of the post-merger combined company) that is entered into during the 10-year period after the Closing or pursuant to the License and Collaboration Agreement (the "Beijing SL License Agreement") with Beijing SL Pharmaceutical Co., Ltd. ("Beijing SL"), but not including the $2.5 million upfront gross payment pursuant to the Beijing SL License Agreement). The CVRs will be issued pursuant to a Contingent Value Rights Agreement (the "CVR Agreement") and Grand Rapids Holders' Representative, LLC (an entity controlled by the three current executive officers of Gemphire) will act as representative of holders of the CVRs. The post-merger combined company has agreed to commit limited resources for a limited period to continue the development of gemcabene under the CVR Agreement. See the section entitled "Agreements Related to the Merger—Contingent Value Rights Agreement" in this proxy statement/prospectus/information statement.

Q:

Who will be the directors of Gemphire following the merger?

A:

Following the consummation of the merger, the size of the Gemphire Board will be increased to include a total of six directors. Pursuant to the terms of the Merger Agreement, the Gemphire Board will be reconstituted such that five of the initial post-Closing directors will be designated by NeuroBo, and one initial post-Closing director will be designated by Gemphire. It is currently anticipated that, following the Closing, the Gemphire Board will be constituted as follows, with one additional director to be designated by NeuroBo prior to Closing:

Q:

Who will be the executive officers of Gemphire immediately following the merger?

A:

Immediately following the consummation of the merger, the executive management team of Gemphire is expected to be composed solely of the members of NeuroBo's executive management team prior to the merger, as follows:

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Q:

What are the material U.S. federal income tax consequences of the merger?

A:

Each of Gemphire and NeuroBo intends to treat the merger to as qualifying as either a tax-free contribution pursuant to Section 351 of the Internal Revenue Code of 1986, as amended (the "Code") or a "reorganization" within the meaning of Section 368(a) of the Code. Mintz, Levin, Cohn, Ferris, Glovsky and Popeo, P.C. will deliver its opinion to NeuroBo that, subject to the Tax Opinion Representations and Assumptions, the merger will qualify as either a tax-free contribution pursuant to Section 351 of Code or a "reorganization" within the meaning of Section 368(a) of the Code. Assuming the merger qualifies as described above, subject to the limitations and qualifications described in the section entitled "The Merger—Material U.S. Federal Income Tax Consequences of the Merger," a U.S. Holder of NeuroBo common stock generally will not recognize any gain or loss for U.S. federal income tax purposes on the exchange of shares of NeuroBo common stock for shares of Gemphire common stock in the merger, except with respect to cash received by such U.S. Holder of NeuroBo common stock in lieu of a fractional share of Gemphire common stock. If any of the Tax Opinion Representations and Assumptions is incorrect, incomplete or inaccurate or is violated, the accuracy of the opinion described above may be affected and the U.S. federal income tax consequences of the merger could differ from those described in this proxy statement/prospectus/information statement.

Please review the information in the section entitled "The Merger—Material U.S. Federal Income Tax Consequences of the Merger" for a more complete description of the material U.S. federal income tax consequences of the merger to U.S. Holders of NeuroBo common stock. The tax consequences to you of the merger will depend on your particular facts and circumstances. You should consult your tax advisors as to the specific tax consequences to you of the merger.

Q:

What are the material U.S. federal income tax consequences of the receipt of CVRs and the Gemphire Reverse Stock Split to Gemphire U.S. Holders?

A:

Gemphire intends to treat the issuance of the CVRs to Gemphire U.S. Holders as a distribution of property with respect to its stock. Please review the information in the section entitled "Agreements Related to the Merger—Contingent Value Rights Agreement—Material U.S. Federal Income Tax Consequences of the Receipt of CVRs" for a more complete description of the material U.S. federal income tax consequences of the receipt of CVRs to Gemphire U.S. Holders, including possible alternative treatments. A Gemphire U.S. Holder generally should not recognize gain or loss upon the Gemphire Reverse Stock Split, except to the extent a Gemphire U.S. Holder receives cash in lieu of a fractional share of Gemphire common stock. Please review the information in the section entitled "Proposal No. 2: Approval of an Amendment to the Gemphire Certificate of Incorporation Effecting the Gemphire Reverse Stock Split—Material U.S. Federal Income Tax Consequences of the Gemphire Reverse Stock Split" for a more complete description of the material U.S. federal income tax consequences of the Gemphire Reverse Stock Split to Gemphire U.S. Holders.

The tax consequences to you of the receipt of CVRs and the Gemphire Reverse Stock Split will depend on your particular facts and circumstances. You should consult your tax advisors as to the specific tax consequences to you.

Q:

What is the Pre-Closing Financing?

A:

Prior to signing the Merger Agreement, NeuroBo entered into subscription agreements with investors for a Series B Preferred Stock financing and received approximate gross proceeds of $24,240,000, the minimum required amount under the Merger Agreement. NeuroBo may enter into additional subscription agreements and receive additional proceeds between signing and closing of the merger (the "Pre-Closing Financing"). The securities of NeuroBo issued in the Pre-Closing Financing were or will be issued pursuant to an exemption from the registration

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requirements of the Securities Act of 1933, as amended. Neither the Gemphire Stockholders nor the NeuroBo Stockholders are being asked to vote on the Pre-Closing Financing. Shares of NeuroBo's Series B Preferred Stock that are issued in the Pre-Closing Financing will be converted into shares of NeuroBo common stock pursuant to the Preferred Stock Conversion and into shares of Gemphire common stock in the merger. Accordingly, by approving Proposal No. 1 relating to the merger, Gemphire Stockholders will also be approving the issuance of shares of Gemphire common stock to be issued in exchange for all shares of NeuroBo common stock issued upon conversion of NeuroBo's Series B Preferred Stock sold in the Pre-Closing Financing.

Q:

As a Gemphire Stockholder, how does the Gemphire Board recommend that I vote?

A:

After careful consideration, the Gemphire Board recommends that Gemphire Stockholders vote "FOR" all of the proposals described in this proxy statement/prospectus/information statement.

Q:

As a NeuroBo Stockholder, how does the board of directors of NeuroBo (the "NeuroBo Board") recommend that I vote?

A:

After careful consideration, the NeuroBo Board recommends that NeuroBo Stockholders execute the written consent to approve the merger, the Merger Agreement, and the transactions contemplated therein, substantially in accordance with the terms of the Merger Agreement and the other agreements contemplated by the Merger Agreement.

Q:

What risks should I consider in deciding whether to vote in favor of the merger or to execute and return the written consent, as applicable?

A:

You should carefully review the section entitled "Risk Factors" in this proxy statement/prospectus/information statement which sets forth certain risks and uncertainties related to the merger, risks and uncertainties to which the combined organization's business will be subject, and risks and uncertainties to which each of Gemphire and NeuroBo, as independent companies, are subject.

Q:

Who can vote at the Gemphire annual meeting?

A:

Only Gemphire Stockholders of record at the close of business on the Record Date will be entitled to vote at the Gemphire annual meeting. As of                , 2019, there were                shares of Gemphire common stock outstanding and entitled to vote.

Stockholder of Record: Shares Registered in Your Name

If, at the close of business on the Record Date, your shares of Gemphire common stock were registered directly in your name with Gemphire's transfer agent, Computershare Trust Company, N.A., then you are a Gemphire Stockholder of record. As a Gemphire Stockholder of record, you may vote in person at the Gemphire annual meeting or vote by proxy. Whether or not you plan to attend the Gemphire annual meeting, please vote as soon as possible by completing and returning the enclosed proxy card or vote by proxy over the telephone or on the internet as instructed on the proxy card to ensure your vote is counted.

Beneficial Owner: Shares Registered in the Name of a Broker or Bank

If, at the close of business on the Record Date, your shares of Gemphire common stock were not held in your name, but rather in an account at a brokerage firm, bank, dealer or other similar organization, then you are the beneficial owner of shares held in "street name" and these proxy materials are being forwarded to you by that organization. The organization holding your account is considered to be the stockholder of record for purposes of voting at the Gemphire annual meeting. As a beneficial owner, you have the right to direct your broker or other agent how to

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vote the shares in your account. You are also invited to attend the Gemphire annual meeting. However, because you are not the stockholder of record, you may not vote your shares in person at the Gemphire annual meeting unless you request and obtain a valid legal proxy from your broker or other agent, giving you the right to vote the shares at the meeting.

Q:

How many votes do I have?

A:

On each matter to be voted upon, you have one vote for each share of Gemphire common stock you own as of the Record Date.

Q:

What is the quorum requirement?

A:

A quorum of Gemphire Stockholders is necessary to hold a valid meeting. A quorum will be present if Gemphire Stockholders holding at least a majority of the outstanding shares of Gemphire common stock entitled to vote at the Gemphire annual meeting are present in person or represented by proxy at the Gemphire annual meeting. On                2019, there were                shares of Gemphire common stock outstanding and entitled to vote. Accordingly, Gemphire expects that the holders of at least                shares of Gemphire common stock must be present at the Gemphire annual meeting for a quorum to exist. Your shares of Gemphire common stock will be counted toward the quorum at the Gemphire annual meeting only if you attend the Gemphire annual meeting in person or are represented at the Gemphire annual meeting by proxy.

Abstentions and broker non-votes will be counted towards the quorum requirement. If there is no quorum, the holders of a majority of shares present and entitled to vote at the meeting in person or represented by proxy may adjourn the Gemphire annual meeting to another date.

Q:

What are "broker non-votes"?

A:

If you hold shares beneficially in street name and do not provide your broker or other agent with voting instructions, your shares may constitute "broker non-votes." Broker non-votes occur on a matter when banks, brokers and other nominees are not permitted to vote on certain non-discretionary matters without instructions from the beneficial owner and instructions are not given. These matters are referred to as "non-routine" matters. Proposal Nos. 1, 4 and 5 are anticipated to be non-routine matters, and Proposal Nos. 2, 3, 6 and 7 are anticipated to be routine matters. Broker non-votes will have no effect on the outcome of Proposal Nos. 1, 4, and 5.

Q:

When do you expect the merger to be consummated?

A:

Gemphire and NeuroBo anticipate that the merger will occur sometime soon after the Gemphire annual meeting to be held on                , 2019, but the companies cannot predict the exact timing. For more information, please see the section entitled "The Merger Agreement—Conditions to the Completion of the Merger" in this proxy statement/prospectus/information statement.

Q:

What do I need to do now?

A:

Gemphire and NeuroBo urge you to read this proxy statement/prospectus/information statement carefully, including its annexes, and to consider how the merger affects you.

If you are a Gemphire Stockholder of record, you may provide your proxy instructions in one of two different ways. First, you can mail your signed proxy card in the enclosed return envelope. You may also provide your proxy instructions via telephone or via the Internet by following the instructions on your proxy card or voting instruction form. Please provide your proxy instructions only once, unless you are revoking a previously delivered proxy instruction, and as soon as possible so that your shares can be voted at the Gemphire annual meeting.

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If you are a NeuroBo Stockholder, you may execute and return your written consent to NeuroBo in accordance with the instructions provided.

Q:

What happens if I do not return a proxy card or otherwise provide proxy instructions, as applicable?

A:

If you are a Gemphire Stockholder, the failure to return your proxy card or otherwise provide proxy instructions will have the same effect as voting "AGAINST" Proposal Nos. 2 and 3.

Q:

When and where is the Gemphire annual meeting and may I vote in person?

A:

The Gemphire annual meeting will be held at                , at                , local time, on                , 2019. Subject to space availability, all Gemphire Stockholders as of the Record Date, or their duly appointed proxies, may attend the Gemphire annual meeting. Since seating is limited, admission to the Gemphire annual meeting will be on a first-come, first-served basis. Registration and seating will begin at                , local time. If your shares of Gemphire common stock are registered directly in your name with Gemphire's transfer agent, you are considered to be the stockholder of record with respect to those shares, and the proxy materials and proxy card are being sent directly to you by Gemphire. If you are a stockholder of record, you may attend the Gemphire annual meeting and vote your shares in person. Even if you plan to attend the Gemphire annual meeting in person, Gemphire requests that you sign and return the enclosed proxy to ensure that your shares will be represented at the Gemphire annual meeting if you become unable to attend. If your shares of Gemphire common stock are held in a brokerage account or by another nominee, you are considered the beneficial owner of shares held in "street name," and the proxy materials are being forwarded to you by your broker or other nominee together with a voting instruction card. As the beneficial owner, you are also invited to attend the Gemphire annual meeting. Because a beneficial owner is not the stockholder of record, you may not vote these shares in person at the Gemphire annual meeting unless you obtain a proxy from the broker, trustee or nominee that holds your shares, giving you the right to vote the shares at the Gemphire annual meeting.

Q:

If my Gemphire shares are held in "street name" by my broker, will my broker vote my shares for me?

A:

Unless your broker has discretionary authority to vote on certain matters, your broker will not be able to vote your shares of Gemphire common stock without instructions from you. Brokers are not expected to have discretionary authority to vote for any of the proposals other than Proposal Nos. 2, 3, 6 and 7. To make sure that your vote is counted, you should instruct your broker to vote your shares, following the procedures provided by your broker.

Q:

May I change my vote after I have submitted a proxy or provided proxy instructions?

A:

Gemphire Stockholders of record, other than those Gemphire Stockholders who are parties to voting agreements, may change their vote at any time before their proxy is voted at the Gemphire annual meeting in one of three ways. First, a Gemphire Stockholder of record can send a written notice to the Secretary of Gemphire stating that it would like to revoke its proxy. Second, a Gemphire Stockholder of record can submit new proxy instructions either on a new proxy card or via telephone or the Internet. Third, a Gemphire Stockholder of record can attend the Gemphire annual meeting and vote in person. Attendance alone will not revoke a proxy. If a Gemphire Stockholder who owns shares of Gemphire common stock in "street name" has instructed a broker to vote its shares of Gemphire common stock, the stockholder must follow directions received from its broker to change those instructions.

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Q:

Who is paying for this proxy solicitation?

A:

Gemphire and NeuroBo will share equally the cost of printing and filing this proxy statement/prospectus/information statement and the proxy card. Arrangements will also be made with brokerage firms and other custodians, nominees and fiduciaries who are record holders of Gemphire common stock for the forwarding of solicitation materials to the beneficial owners of Gemphire common stock. Gemphire will reimburse these brokers, custodians, nominees and fiduciaries for the reasonable out-of-pocket expenses they incur in connection with the forwarding of solicitation materials.

Gemphire has engaged The Proxy Advisory Group, LLC to assist in the solicitation of proxies and provide related advice and informational support, for a services fee and the reimbursement of customary disbursements, which are not expected to exceed $20,000 in total.

Q:

Who can help answer my questions?

A:

If you are a Gemphire Stockholder and would like additional copies, without charge, of this proxy statement/prospectus/information statement or if you have questions about the merger, including the procedures for voting your shares, you should contact:

Gemphire Therapeutics Inc.
P.O. Box 130235
Ann Arbor, MI 48113
Telephone: (734) 245-1700
Attn: Secretary

If you are a NeuroBo Stockholder, and would like additional copies, without charge, of this proxy statement/prospectus/information statement or if you have questions about the merger, including the procedures for voting your shares, you should contact:

NeuroBo Pharmaceuticals, Inc.
177 Huntington Avenue, Suite 1700
Boston, MA 02115
(617) 313-7331
Attn: Secretary

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