EXHIBIT 10.4

                         AMENDMENT TO LICENSE AGREEMENT

      This Amendment to License Agreement ("Amendment") is entered into as of
September 5, 2000, by and between BUKWANG PHARM. IND. CO., LTD., with its
principal offices at 398-01, Daebang-Dong, Dongjak-Ku, Seoul 156-020, Korea
("Bukwang") and TRIANGLE PHARMACEUTICALS, INC., with its principal offices
located at 4 University Place, 4611 University Drive, Durham, North Carolina
27707 ("Triangle") and amends certain terms of that certain License Agreement,
dated as of February 27, 1998, between Bukwang and Triangle, as amended April 1,
1999 (the "Agreement"). Capitalized terms not defined herein shall have the
meanings given them in the Agreement.

                                    RECITALS

      A. Bukwang and Triangle have previously entered into the Agreement,
pursuant to which Bukwang has licensed certain patent rights and know-how to
Triangle relating to a compound known as L-FMAU.

      B. Triangle has certain obligations to make a milestone payment upon the
*** and upon the *** .

      C. As part of its diligence efforts in respect of L-FMAU, Triangle is
required to use its best efforts to file an NDA for a Licensed Product with the
FDA *** .

      D. Bukwang and Triangle desire to amend and clarify certain terms of the

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Agreement relating to such milestone payment and due diligence time limits.

      NOW, THEREFORE, for good and valuable consideration, Triangle and Bukwang
hereby agree as follows:

      1.    Amendments. The Agreement is hereby amended as follows:

            (a)   Section 1.15. Delete Section 1.15 and replace it with the
                  following: "IND" shall mean a U.S. or Canadian Investigational
                  New Drug Application or its equivalent in either country."

            (b)   Section 1.22. Delete Section 1.22 and replace it with the
                  following: "`NDA' shall mean a New Drug Application or its
                  equivalent filed in the U.S., China or, in the case of Europe,
                  with the European Agency for the Evaluation of Medicinal
                  Products."

            (c)   Subsection 6.2(a)(i). Delete Subsection 6.2(a)(i) and replace
                  it as follows: "(i) files what it reasonably believes to be a
                  complete NDA for a Licensed Product for HBV within *** after
                  the Effective Date; provided, however, said *** period shall
                  be subject to up to *** extensions of *** , at Triangle's
                  election, by payment to Bukwang of a sum of $ *** for each ***
                  extensions and $ *** for each *** extensions."

      2.    General Terms. The Agreement, as amended by this Amendment,
            constitutes the entire agreement between Bukwang and Triangle or
            regarding the subject matters contained therein and herein. In the
            event of any conflict between the provisions of the Agreement and
            this

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            Amendment, the provisions of this Amendment shall govern and
            control. This Amendment shall be governed by, and construed in
            accordance with, the laws of the State of Georgia without regard to
            its conflicts of laws principles. This Amendment may be executed in
            any number of counterparts, each of which shall be deemed an
            original and all of which shall constitute one and the same
            instrument. If any provision of this Amendment is for any reason
            held to be ineffective, unenforceable or illegal, such condition
            shall not affect the validity or enforceability of any of the
            remaining portions hereof; provided, further, that the parties shall
            negotiate in good faith to replace any ineffective, unenforceable or
            illegal provision with an effective replacement as soon as is
            practical.

      IN WITNESS WHEREOF, Bukwang and Triangle have each executed this Amendment
through an authorized officer as of the date written below.

                                    BUKWANG PHARM. IND. CO., LTD.

                                    By:   /s/ Sung-Koo Lee
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                                    Its:  Managing Director
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                                    Date: September 21, 2000
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                                    TRIANGLE PHARMACEUTICALS, INC.

                                    By:   /s/ Chris A. Rallis
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                                    Its:  President and COO
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                                    Date: September 5, 2000
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