SCHEDULE 13D

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13D

Under the Securities Exchange Act of 1934

Melinta Therapeutics, Inc.

(Name of Issuer)

Common Stock, par value $0.001 per share

(Title of Class of Securities)

58549G 100

(CUSIP Number)

Anna Kim, Esq.

Vatera Healthcare Partners LLC

c/o Vatera Holdings LLC

499 Park Ave, 23^rd Floor

New York, NY 10022

(212) 590-2950

With a copy to:

Gordon R. Caplan, Esq.

Sean M. Ewen, Esq.

Willkie Farr & Gallagher LLP

787 Seventh Avenue

New York, New York 10019

212-728-8000

(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)

November 3, 2017

(Date of Event which Requires Filing of this Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition which is the subject of this statement on Schedule 13D (this “Schedule 13D”), and is filing this Schedule 13D because of Rule 13d-1(e), 13d-1(f) or 13d-1(g), check the following box.  ☐

Note: Schedules filed in paper format shall include a signed original and five copies of the schedule, including all exhibits. See Rule 13d-7 for other parties to whom copies are to be sent.

The information required on 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 (the “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).

SCHEDULE 13D

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Item 1. Security and Issuer.

This statement relates to the common stock, par value $0.001 per share (the “Common Stock”), of Melinta Therapeutics, Inc. (formerly known as Cempra, Inc.) (the “Issuer”). The shares of Common Stock beneficially owned by the Reporting Persons as reported herein are referred to as the “Shares.” The principal executive office of the Issuer is located at 300 George Street, Suite 301, New Haven, CT 06511. Information given in response to each item shall be deemed incorporated by reference in all other items, as applicable.

Item 2. Identity and Background.

The persons identified in (i) through (iii) above are herein referred to as the “Reporting Persons.” Neither the fact of this filing nor anything contained herein shall be deemed to be an admission by the Reporting Persons that they have formed a group.

The Reporting Persons have entered into a Joint Filing Agreement, dated November 13, 2017, a copy of which is attached as Exhibit 99.1 hereto, pursuant to which the Reporting Persons have agreed to file this Schedule 13D jointly in accordance with the provisions of Rule 13d-1(k)(1) of the Act.

Mr. Ferro serves as the Chief Executive Officer, Chief Investment Officer and Managing Member of Vatera Holdings and may be deemed to control the Reporting Persons. Mr. Ferro also serves as a director and non-executive Chairman of the Issuer’s Board of Directors. Other than Mr. Ferro, there are no persons who serve in the capacity of an executive officer, manager or director of the Reporting Persons.

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Item 3. Source or Amount of Funds or Other Consideration.

On November 3, 2017, Cempra, Inc., a Delaware corporation (“Cempra”), completed its business combination with Melinta Therapeutics, Inc., a privately held Delaware corporation (“Melinta”), in accordance with the terms of that certain Agreement and Plan of Merger and Reorganization, dated as of August 8, 2017, as amended on each of September 6, 2017 and October 24, 2017 (as so amended, the “Merger Agreement”) by and among Cempra, Melinta and Castle Acquisition Corp., a Delaware corporation and wholly owned subsidiary of Cempra (“Merger Sub”). On November 3, 2017, pursuant to the Merger Agreement, Merger Sub merged with and into Melinta, with Melinta surviving the merger and becoming a wholly owned subsidiary of Cempra (the “Merger”). Concurrently with the effectiveness of the Merger, Cempra changed its name to Melinta Therapeutics, Inc., thereby becoming the Issuer, and Melinta changed its name to Melinta Subsidiary Corp.

At the effective time of the Merger, each outstanding share of Melinta’s common stock (including shares of Melinta common stock to be issued on conversion of Melinta’s outstanding convertible promissory notes and preferred stock, including convertible promissory notes and preferred stock held by Vatera Healthcare) was converted into the right to receive Common Stock of Cempra in an amount equal to the exchange ratio calculated pursuant to the Merger Agreement (the “Exchange Ratio”) (except that Melinta stockholders who did not meet the definition of an “accredited investor” under applicable federal securities law received a per-share cash payment based on the closing price of Cempra Shares on the closing date of the Merger multiplied by the Exchange Ratio). Vatera Healthcare, in accordance with the exchange of its shares pursuant to the Exchange Ratio and under the terms of the Merger Agreement, received the Shares. Concurrent with the closing of the Merger, Cempra effected a 5-to-1 reverse stock split with respect to its Common Stock.

As described above, the Shares beneficially owned by the Reporting Persons were all acquired in the Merger pursuant to the terms of the Merger Agreement.

Item 4. Purpose of Transaction.

The Reporting Persons acquired the Shares in the Merger pursuant to the terms of the Merger Agreement, which was executed by the parties thereto to combine the business and operations of Melinta and Cempra. All of the Shares that may be deemed to be beneficially owned by the Reporting Persons, as reported herein, were acquired for investment purposes. None of the Reporting Persons other than Vatera Healthcare directly owns the Shares.

As of November 3, 2017, the Reporting Persons beneficially own 30.7% of the outstanding shares of Common Stock of the Issuer. At the effective time of the Merger, the Board of Directors of the Issuer was reconstituted to nine members, including four directors designated by Melinta: Mr. Ferro, Jay Galeota, Cecilia Gonzalo and Thomas P. Koestler, Ph.D. Ms. Gonzalo is a managing director of Vatera Holdings and Dr. Koestler is an executive director of Vatera Holdings. The Reporting Persons intend to participate in the management of the Company through the representation by Mr. Ferro, Ms. Gonzalo and Dr. Koestler on the Issuer’s Board of Directors.

In addition, the Reporting Persons will routinely monitor the Issuer’s operations, prospects, business development, management, competitive and strategic matters, capital structure, capital raising needs and any proposals received from third parties with respect to the Issuer. The Reporting Persons may discuss such matters with management or directors of the Issuer, existing or potential strategic partners, persons who have expressed an interest in acquiring all or a portion of the Issuer’s equity interests or in engaging in a strategic transaction with the Reporting Persons regarding the Issuer, sources of credit and other investors. In evaluating the Issuer, the Reporting Persons will also consider alternative investment opportunities available to them, the Reporting Persons’ liquidity requirements and other investment considerations. While none of the Reporting Persons have, other than as described in this Schedule 13D, any current plans or proposals that relate to or would result in any of the matters described in subsections (a) through (j) of Item 4 of Schedule 13D, the factors described in this Item 4 may materially affect, and result in, the Reporting Persons: (1) modifying or disposing of all or a portion of their investment in the Issuer, (2) exchanging information with others regarding the Issuer pursuant to appropriate confidentiality or similar agreements, (3) proposing changes in the Issuer’s operations, governance or capitalization, or (4) proposing one or more of the other actions described in subsections (a) through (j) of Item 4 of Schedule 13D.

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In addition, depending upon overall market conditions, other investment opportunities available to the Reporting Persons, and the availability of securities of the Issuer at prices that would make the purchase or sale of such securities desirable, the Reporting Persons may endeavor (i) to increase or decrease their respective positions in the Issuer through, among other things, the purchase or sale of securities of the Issuer on the open market or in private transactions, including through any trading plan created under Rule 10b5-1(c) or otherwise, on such terms and at such times as the Reporting Persons may deem advisable and/or (ii) to enter into transactions that increase or hedge their economic exposure to the Common Stock without affecting their beneficial ownership of shares of Common Stock.

Item 5. Interest in Securities of the Issuer.

Item 6. Contracts, Arrangements, Understandings or Relationships with Respect to Securities of the Issuer.

The responses to Item 4 and Item 5 are incorporated herein by reference.

The Issuer is party to a Registration Rights Agreement, dated as of November 3, 2017, with certain holders of Common Stock including Vatera Healthcare (the “Registration Rights Agreement”), pursuant to which the Issuer is obligated to file, within 90 calendar days from the date of execution of the Registration Rights Agreement, a shelf registration statement on Form S-3 providing for the resale by such holders of the Issuer’s Common Stock issued or issuable to such holders in connection with the Merger. Vatera Healthcare is entitled to two underwritten offerings under such shelf registration statement. The foregoing description of the Registration Rights Agreement does not purport to be complete and is qualified in its entirety by reference to the full text of the Registration Rights Agreement which was attached as Exhibit 10.1 to the Issuer’s Current Report on Form 8-K, filed with the SEC on November 3, 2017.

Concurrently with the execution of the Merger Agreement, certain Melinta stockholders, including Vatera Healthcare and Mr. Ferro, entered into voting and lock-up agreements with Cempra, dated August 8, 2017. The voting and lock-up agreements, provide for, among other things, a 180-day lock-up on the sale or other disposition of Common Stock by such stockholders commencing upon consummation of the Merger, which lock-up applies to all of the Shares held by the Reporting Persons. The foregoing description of the voting and lock-up agreements does not purport to be complete and is qualified in its entirety by reference to the full text of the voting and lock-up agreement which was attached as Annex D-2 to the Issuer’s definitive proxy statement on Schedule 14A, filed with the SEC on October 5, 2017.

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Item 7. Materials to be Filed as Exhibits

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SIGNATURES

After reasonable inquiry and to the best of its knowledge and belief, each of the undersigned certifies that the information set forth in this Schedule 13D is true, complete and correct.

Dated: November 13, 2017

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Exhibit 1

JOINT FILING AGREEMENT

In accordance with Rule 13d-l (k) (1) under the Securities Exchange Act of 1934, as amended, the persons named below agree to the joint filing on behalf of each of them of a Statement on Schedule 13D dated November 13, 2017 (including amendments thereto) with respect to the Common Stock of Melinta Therapeutics, Inc.

This Joint Filing Agreement shall be filed as an Exhibit to such Statement. The undersigned acknowledge and agree that the foregoing Statement on Schedule 13D is filed on behalf of each of the undersigned and that all subsequent amendments to this Statement on Schedule 13D shall be filed on behalf of each of the undersigned without the necessity of filing additional Joint Filing Agreements. The undersigned acknowledge that each shall be responsible for the timely filing of such amendments, and for the completeness and accuracy of the information concerning him or it contained therein, but shall not be responsible for the completeness and accuracy of the information concerning the other entities or persons, except to the extent that he or it knows or has reason to believe that such information is inaccurate.

IN WITNESS WHEREOF, the undersigned hereby execute this Joint Filing Agreement as of November 13, 2017.