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                                  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 9, 1998


                                     0-27352
                            (Commission File Number)


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


                                 HYBRIDON, INC.
            (Exact name of registrant as specified in its charter)


               Delaware                                   3072298
         (State of Incorporation)                      (IRS Employer
                                                   Identification Number)


               620 Memorial Drive, Cambridge, Massachusetts 02139
              (Address of registrant's principal executive office)


                                 (617) 528-7000
                         (Registrant's telephone number)


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



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ITEM 9.  SALES OF EQUITY SECURITIES PURSUANT TO REGULATION S

         On February 9, 1998, as part of a private  placement (the  "Offering"),
Hybridon,  Inc. (the "Company") sold $2,384,000 in principal amount of Notes due
2007 (the "Offering  Notes"),  and warrants (the  "Warrants") to purchase common
stock,  par value $.001 per share, of the Company,  pursuant to the terms of the
Offering  described  in its Current  Report on Form 8-K,  and the press  release
filed as an exhibit  thereto,  dated  January  22, 1998 (the  "January  22, 1998
8-K").  The  Offering  Notes were issued at face value in offshore  transactions
pursuant to  Regulation  S  promulgated  under the  Securities  Act of 1933,  as
amended (the  "Securities  Act").  The  purchasers  of the  Offering  Notes were
accredited   investors  (as  defined  in  Regulation  D  promulgated  under  the
Securities Act).

         The  terms of  conversion  of the  Offering  Notes and the terms of the
Warrants are described in the January 22, 1998 8-K.

         The net  proceeds  to the  Company  from  the  Offering  are  presently
intended to be used for  general  corporate  purposes,  primarily  research  and
product development activities, including costs of preparing Investigational New
Drug applications and conducting  preclinical  studies and clinical trials,  the
payment of payroll  and other  accounts  payable and for debt  service  required
under the Company's debt obligations.




                                   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, thereunto duly authorized.


                               HYBRIDON, INC.

                               By:   /s/ E. ANDREWS GRINSTEAD, III
                                     ------------------------------------
                                     Name:  E. Andrews Grinstead, III
                                     Title: Chairman of the Board, President and
                                            Chief Executive Officer

                               Date: February 24, 1998




                        KRAMER, LEVIN, NAFTALIS & FRANKEL
                                919 THIRD AVENUE
                           NEW YORK, N.Y. 10022 - 3852
                               (212) 715 - 9100
                                                                             FAX
                                                                  (212) 715-8000
                                                                           -----
                                                          WRITER'S DIRECT NUMBER
                                                                  (212) 715-9414
                                February 24, 1998



VIA EDGAR

Securities and Exchange Commission
Judiciary Plaza
450 Fifth Street, N.W.
Washington, D.C. 20549

    Re:  Hybridon, Inc.
         Filing of Current Report on Form 8-K

Ladies and Gentlemen:

         On behalf of Hybridon,  Inc., a Delaware  corporation  (the "Company"),
pursuant to the rules and regulations  promulgated under the Securities Exchange
Act of 1934, as amended, we are transmitting herewith via EDGAR a Current Report
on Form 8-K of the Company.

         Please  address any questions or comments to the  undersigned  at (212)
715-9414.



                                    Very truly yours,

                                    /s/ A. BENJAMIN WIENER
                                    ----------------------
                                    A. Benjamin Wiener


cc:   Hybridon, Inc.