UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d)

of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): February 10, 2016

Celladon Corporation

(Exact name of registrant as specified in its charter)

Registrant’s telephone number, including area code: (858) 350-4355

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligations of the registrant under any of the following provisions:

Item 8.01 Other Events.

On February 10, 2016, Celladon Corporation (“Celladon”) issued a press release announcing that it has set a date for a special meeting of its stockholders to vote on matters related to the previously announced proposed merger with Eiger BioPharmaceuticals, Inc. (“Eiger”). The special meeting will be held at 9:00 a.m., local time, on March 21, 2016 at 12255 El Camino Real, Suite 300, San Diego, California 92130. Celladon stockholders of record as of the close of business on February 12, 2016 are entitled to receive notice of, and to vote at, the special meeting.

A copy of the press release is attached hereto as Exhibit 99.1 and incorporated by reference herein.

Additional Information about the Merger and Where to Find It

In connection with the proposed merger, Celladon has filed a registration statement on Form S-4 with the Securities and Exchange Commission (the “SEC”), including a proxy statement/prospectus/information statement, but the registration statement has not yet become effective. The proxy statement/prospectus/information statement and any other relevant documents filed by Celladon with the SEC may be obtained free of charge at the SEC web site at www.sec.gov. In addition, investors and security holders may obtain free copies of the documents filed with the SEC by Celladon by directing a written request to: Celladon Corporation, 12707 High Bluff Dr. #200, San Diego, CA 92130, Attention: Investor Relations. Investors and security holders are urged to read the proxy statement/prospectus/information statement and the other relevant materials before making any voting or investment decision with respect to the proposed merger.

This communication shall not constitute an offer to sell or the solicitation of an offer to sell or the solicitation of an offer to buy any securities, nor shall there be any sale of securities in any jurisdiction in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such jurisdiction. No offering of securities in connection with the proposed merger shall be made except by means of a prospectus meeting the requirements of Section 10 of the Securities Act of 1933, as amended.

Participants in the Solicitation

Celladon and its directors and executive officers and Eiger and its directors and executive officers may be deemed to be participants in the solicitation of proxies from the stockholders of Celladon in connection with the proposed transaction. Information regarding the special interests of these directors and executive officers in the merger is included in the proxy statement/prospectus/information statement referred to above. Additional information regarding the directors and executive officers of Celladon is also included in Celladon’s Annual Report on Form 10-K for the year ended December 31, 2014 and the proxy statement for Celladon’s 2015 Annual Meeting of Stockholders. These documents are available free of charge at the SEC web site at www.sec.gov and from Investor Relations at Celladon at the address described above.

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Item 9.01 Financial Statements and Exhibits.

Reference is made to the Exhibit Index included with this Current Report on Form 8-K.

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SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

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EXHIBIT INDEX