UNITED STATES

  SECURITIES AND EXCHANGE COMMISSION

  WASHINGTON, D.C. 20549 

  

  SCHEDULE 13G 

UNDER THE SECURITIES EXCHANGE ACT OF 1934

    (Amendment No. 2)*



  Eiger BioPharmaceuticals, Inc.

  (Name of Issuer)

  

  Common Stock, $0.001 par value per share 

  (Title of Class of Securities)

  

  28249U 105

  (CUSIP Number)

  

  March 22, 2016

  (Date of Event Which Requires Filing of this Statement)


  

  Check the appropriate box to designate the rule pursuant to which this Schedule

  is filed:

  

  |_| Rule 13d-1(b)

  |X| Rule 13d-1(c)

  |_| Rule 13d-1(d)

  

  *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 disclosures provided in a prior cover page.

  

  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 ("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).
CUSIP No.

  28249U 105

  --------------------------------------------------------------------------------

  1) Names of Reporting  Persons. PFIZER INC.

  I.R.S. Identification Nos. of Above Persons (entities only) 13-5315170

  --------------------------------------------------------------------------------

  2) Check the Appropriate  Box if a Member of a Group (See Instructions)

  (a) |_|

  (b) |_|

  --------------------------------------------------------------------------------

  3) SEC Use Only

  --------------------------------------------------------------------------------

  4) Citizenship or Place  of Organization

  Delaware

  --------------------------------------------------------------------------------

  
    
            NUMBER OF

        SHARES 

        BENEFICIALLY 

        OWNED BY EACH    REPORTING

        PERSON WITH: 
      
5. Sole Voting Power      121,899
    
    
      
6. Shared Voting Power    -0-
    
    
      
7. Sole Dispositive    Power 121,899
    
    
      
8. Shared Dispositive    Power -0-
    
  

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  9) Aggregate Amount  Beneficially Owned by Each Reporting Person 121,899

  10) Check if the  Aggregate Amount in Row (9) Excludes Certain Shares

  (See Instructions) |_|

  11) Percent of Class  Represented by Amount in Item 9  1.76%

  12) Type of Reporting  Person (See Instructions)   CO

   

  ITEM 1.

  (A) NAME OF ISSUER: Celladon Corporation

  (B) ADDRESS OF ISSUER'S  PRINCIPAL EXECUTIVE OFFICE:

    350 Cambridge Avenue, Suite 350, Palo Alto CA 94306

  ITEM 2.

  (A) NAME OF PERSONS  FILING: PFIZER INC.

  (B) ADDRESS OF PRINCIPAL  BUSINESS OFFICE OR IF NONE, RESIDENCE:

  235 E. 42nd Street, New York, NY 10017

  (C) CITIZENSHIP:  DELAWARE, U.S.A.

  (D) TITLE OF CLASS OF  SECURITIES: COMMON STOCK

  (E) CUSIP NUMBER:  28249U 105

  ITEM 3. 

  Not applicable. 

  ITEM 4. OWNERSHIP.

  (a) Amount beneficially  owned: 121,899

  (b) Percent of class: 1.76%

  (c) Number of shares as  to which the person has: 

  (i) Sole power to vote  or to direct the vote: 121,899

(ii) Shared power to  vote or to direct the vote: 0

  (iii) Sole power to  dispose or to direct the disposition of:  121,899

  (iv) Shared power to  dispose or to direct the disposition of:    0
On   March 22, 2016, Eiger BioPharmaceuticals, Inc., formerly known as Celladon   Corporation (the “Company”) completed its business combination with what   was then known as “Eiger BioPharmaceuticals, Inc.” (“Eiger”) in   accordance with the terms of the Agreement and Plan of Merger and   Reorganization, dated as of November 18, 2015, by and among the Company,   Celladon Merger Sub, Inc. (“Merger Sub”), and Eiger (the “Merger   Agreement”), pursuant to which Merger Sub merged with and into Eiger, with   Eiger surviving as a wholly owned subsidiary of the Company (the   “Merger”). Also on March 22, 2016, in connection with, and prior to the   completion of, the Merger, the Company effected a 15-for-1 reverse stock split   of its common stock (the “Reverse Stock Split”), and immediately   following the Merger, the Company changed its name to “Eiger BioPharmaceuticals,   Inc.”
The ownership percentage of the Reporting Person  set forth in Row 11 of the cover page hereto has been calculated based on 6,945,424 shares of the Company’s   common stock outstanding as of March 23, 2016, as reported in the Issuer’s Form 10-K  filed with the Securities and Exchange Commission on March 30, 2016.
ITEM 5. OWNERSHIP OF  FIVE PERCENT OR LESS OF A CLASS

  | X |

  ITEM 6. OWNERSHIP OF  MORE THAN FIVE PERCENT ON BEHALF OF ANOTHER PERSON

  Not applicable.

  ITEM 7.   IDENTIFICATION AND CLASSIFICATION OF THE SUBSIDIARY WHICH ACQUIRED THE  SECURITY BEING REPORTED ON BY THE PARENT HOLDING COMPANY

  Not applicable.

  ITEM 8. IDENTIFICATION  AND CLASSIFICATION OF MEMBERS OF THE GROUP

  Not applicable.

  ITEM 9. NOTICE OF  DISSOLUTION OF GROUP

  Not applicable.

  ITEM 10. CERTIFICATION.

  

By signing below I  certify that, to the best of my knowledge and belief, the  securities referred to above were not acquired and are not held for the purpose  of or with the effect of changing or influencing the control of the issuer of  the securities and were not acquired and are not held in connection with or as  a  participant in any transaction having that purpose or effect.


   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: April   4, 2016

  

  PFIZER INC. 

  

  By: /s/ Susan Grant

  Name: Susan Grant

  Title: Assistant Secretary