EXHIBIT 10.1

                           AMENDMENT NUMBER TWO TO THE
                      AGREEMENT AND PLAN OF REORGANIZATION

      This Amendment Number Two (this "Amendment") to the Agreement and Plan of
Reorganization dated as of June 30, 1997 (the "Original Agreement") as amended
February 28, 1999 (the "Agreement") among Triangle Pharmaceuticals, Inc.
("Triangle"), Project Z Corporation ("Project Z") and Avid Corporation ("Avid"),
is made as of this 24th day of March, 2000, by and among Triangle, Avid and the
Securityholder Agent (as such term is defined in the Original Agreement) (the
"Securityholder Agent"), on behalf of and as attorney-in-fact for all of the
stockholders, optionholders and warrantholders of Avid immediately prior to the
merger of Project Z with and into Avid (the "Former Avid Stockholders").
Capitalized terms used herein which are not defined herein shall have the
definitions ascribed to them in the Agreement.

                                    RECITALS

      A. Triangle, Project Z and Avid entered into the Original Agreement,
pursuant to which Project Z merged with and into Avid on August 28, 1997, and
Avid became a wholly-owned subsidiary of Triangle.

      B. Triangle, Avid (including its capacity as successor to Project Z) and
the Securityholder Agent, entered into Amendment Number One to the Agreement and
Plan of Reorganization, dated February 28, 1999, extending to thirty (30) months
the eighteen (18) month period set forth in Section 1.6(b)(ii)(B) of the
Original Agreement.

      C. Triangle, Avid and the Securityholder Agent, on behalf of and as
attorney-in-fact for the Former Avid Stockholders, desire (i) to extend the
thirty (30) month period set forth in Section 1.6(b)(ii)(B) of the Agreement
after which, if Triangle has not Initiated a Definitive Clinical Trial with the
Lead Compound or elected in writing to continue the development of the Lead
Compound, the Securityholder Agent will have the right to exercise the Lead
Compound Option, and (ii) to amend certain other provisions of the Agreement as
set forth herein.

      NOW, THEREFORE, in consideration of the foregoing and the promises and
covenants contained herein, and for other good and valuable consideration the
receipt and sufficiency of which is hereby acknowledged, the parties hereto
agree as follows:

      1. AMENDMENTS TO AGREEMENT.

            1.1 Section 1.6(b). The first paragraph of Section 1.6(b) is hereby
amended and restated in its entirety as follows:

                  "(b) Stock Consideration. The "Stock Consideration" shall be
      the number of shares of Parent Common Stock equal to the sum of (v) the
      First Payment (as defined in Section 1.6(b)(i) below) plus (x) the Second
      Payment (as defined in Amendment Number One to this Agreement) plus (y)
      the Third Payment (as defined in Amendment Number Two to this Agreement)
      plus (z) the Milestone Payments (as defined in Section 1.6(b)(ii) below)."

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            1.2 Section 1.6(b)(ii)(A). Section 1.6(b)(ii)(A) of the Agreement is
hereby amended and restated in its entirety as follows:

                  "(A) In the event that Parent, in its sole discretion, (x)
      Initiates (as defined in Section 1.6(b)(iii) below) a Definitive Clinical
      Trial (as defined in Section 1.6(b)(iii) below) with the Lead Compound (as
      defined in Section 1.6(b)(iii) below), or (y) notifies the Securityholder
      Agent (as defined in Section 7.2(g) below) in a writing that specifically
      references this Section 1.6(b)(ii)(A) of its election to continue the
      development of the Lead Compound even if Parent has not Initiated a
      Definitive Clinical Trial with the Lead Compound, Parent shall within
      seventy-five (75) days thereafter make available to the Exchange Agent (as
      defined in Section 1.10(a) below) for distribution pursuant to Section
      1.10, 1,150,000 shares of Parent Common Stock."

            1.3 Section 1.6(b)(ii)(B). Section 1.6(b)(ii)(B) of the Agreement is
hereby amended and restated in its entirety as follows:

                  "(B) If neither of the conditions described in Section
      1.6(b)(ii)(A) above is satisfied on or prior to forty-eight (48) months
      after the Closing Date and the Securityholder Agent elects not to exercise
      the Lead Compound Option (as defined in Section 5.17 below) within the
      thirty (30) day period set forth in Section 5.17 below, Parent shall
      within seventy-five (75) days thereafter make available to the Exchange
      Agent for distribution pursuant to Section 1.10, 100,000 shares of Parent
      Common Stock."

            1.4 Section 1.8(c)(i)(A). Section 1.8(c)(i)(A) of the Agreement is
hereby amended and restated in its entirety as follows:

                  "(A) At the Effective Time, each Assumed Option shall be, in
      connection with the Merger, assumed by Parent. Each Assumed Option so
      assumed by Parent under this Agreement shall be amended prior to the
      Effective Time to provide that from and after the Effective Time such
      Assumed Option (1) may be exercised through a cashless exercise procedure
      (to the extent that the Assumed Option does not already permit the holder
      thereof to do so) and may be exercised notwithstanding the failure of the
      holder thereof to enter or remain in the employ of Parent or the Company
      following the Merger, (2) may not be exercised at any time prior to the
      earlier of (a) forty-eight (48) months after the Closing Date and (b) the
      date, if any, of the written notice from the Securityholder Agent
      addressed to the last known domicile address of the holder of such Assumed
      Option informing such holder that one of the conditions described in
      Section 1.6(b)(ii)(A) above has been satisfied (the earlier of such dates
      being the "Option Exercise Date"), (3) may not be exercised at any time
      after 5:00 p.m. eastern standard time on the date that is forty-five (45)
      days after the Option Exercise Date, and (4) represents only the right to
      receive upon exercise the portion of the Merger Consideration issuable to
      such holder pursuant to Section 1.7 above. Except as so amended, each
      Assumed Option shall continue to have,


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      and be subject to, the same terms and conditions set forth in the Option
      Plan under which it was issued and/or as provided in the respective option
      agreements governing such Assumed Option immediately prior to the
      Effective Time. Parent shall reserve from the Cash Distribution the
      amount, if any, that the holders of the Assumed Options would have
      received had all of the Assumed Options and all of the Assumed Warrants
      been exercised in full immediately prior to the Effective Time (assuming
      that the exercise price was paid in cash). The portion of the Cash
      Distribution reserved by Parent for issuance upon exercise of the Assumed
      Options is referred to as the "Assumed Option Amount." "

            1.5 Section 1.8(d)(i)(A). Section 1.8(d)(i)(A) of the Agreement is
hereby amended and restated in its entirety as follows:

                  "(A) At the Effective Time, each Assumed Warrant shall be, in
      connection with the Merger, assumed by Parent. Each Assumed Warrant so
      assumed by Parent under this Agreement shall be amended prior to the
      Effective Time to provide that from and after the Effective Time such
      Warrant (1) may be exercised through a cashless exercise procedure (to the
      extent that the Assumed Warrant does not already permit the holder thereof
      to do so), (2) may not be exercised at any time prior to the earlier of
      (a) forty-eight (48) months after the Closing Date and (b) the date, if
      any, of the written notice from the Securityholder Agent addressed to the
      last known domicile address of the holder of such Assumed Warrant
      informing such holder that one of the conditions described in Section
      1.6(b)(ii)(A) above has been satisfied (the earlier of such dates being
      the "Warrant Exercise Date"), (3) may not be exercised at any time after
      5:00 p.m. eastern standard time on the date that is forty-five (45) days
      after the Warrant Exercise Date, and (4) represents only the right to
      receive upon exercise the portion of the Merger Consideration issuable to
      such holder pursuant to Section 1.7 above. Except as so amended, each
      Assumed Warrant shall continue to have, and be subject to, the same terms
      and conditions as provided in the respective Assumed Warrant agreement
      immediately prior to the Effective Time. Parent shall reserve from the
      Cash Distribution the amount, if any, that the holders of the Assumed
      Warrants would have received had all of the Assumed Warrants and all of
      the Assumed Options been exercised in full immediately prior to the
      Effective Time (assuming that the exercise price was paid in cash). The
      portion of the Cash Distribution reserved by Parent for issuance upon
      exercise of the Assumed Warrants is referred to as the "Assumed Warrant
      Amount." "

            1.6 Section 5.17. The first paragraph of Section 5.17 of the
Agreement is hereby amended and restated in its entirety as follows:

                  "5.17 Option to Obtain Rights to Lead Compound. In the event
      that neither of the conditions described in Section 1.6(b)(ii)(A) is
      satisfied on or prior to the date that is forty-eight (48) months after
      the Closing Date, the Securityholder Agent shall have the option ("Lead
      Compound Option"), subject to the conditions and on the terms described
      below, to acquire on behalf of each holder of any Company Capital Stock
      outstanding immediately prior to the


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      Effective Time and each holder of an Assumed Option or an Assumed Warrant
      that is timely and properly exercised after the Closing (together, the
      "Former Company Stockholders") pursuant to the Technology Transfer
      Agreement in the form attached hereto as Exhibit 5.17 (the "Technology
      Transfer Agreement"): (i) all of Parent's and the Company's rights in the
      Lead Compound, in all improvements solely and exclusively of, and
      enhancements solely and exclusively to, the Lead Compound (the "Lead
      Compound Improvements") and in all documents and data created solely and
      exclusively in connection with the development of the Lead Compound (the
      "Lead Compound Information") (and in both the case of Lead Compound
      Improvements and Lead Compound Information, not in any way related to any
      of the other compounds, technologies or assets of Parent or the Company),
      and (ii) one copy of all documents that contain any data regarding
      clinical trials of the Lead Compound in combination with other drugs or
      drug candidates, redacted to exclude therefrom any other information
      contained therein (together with the Lead Compound Information, the "Lead
      Compound Documents"). In the event the Securityholder Agent delivers
      written notice to Parent of his or her election to exercise the Lead
      Compound Option within thirty (30) calendar days after the date of the
      Parent Notice (as defined in Section 5.17(a) below), Parent shall
      thereafter, subject to and in compliance with good medical and clinical
      trial practices, promptly and permanently cease, and shall cause the
      Company to cease, all development and use of the Lead Compound, the Lead
      Compound Improvements and the Lead Compound Documents (collectively, the
      "Lead Compound Rights")."

            1.7 Section 5.1(d). Section 5.1(d) is hereby amended and restated in
its entirety as follows:

                  (i) If one of the conditions described in Section
      1.6(b)(ii)(A) above is satisfied, Parent shall use its reasonable efforts
      to file a Registration Statement on Form S-3 with the SEC covering the
      resale of the shares of Parent Common Stock issued in the Merger. Such
      registration, including Parent's obligation to file such Registration
      Statement on Form S-3, shall be subject to the terms and conditions set
      forth in the Declaration of Registration Rights attached hereto as Exhibit
      5.1(d).

                  (ii) Parent shall file a Registration Statement on Form S-3
      with the SEC covering the resale of the shares issued in connection with
      the Third Payment (as defined in Amendment Number Two to this Agreement)
      on or before June 1, 2000. Such registration, including Parent's
      obligation to file such Registration Statement on Form S-3, shall be
      subject to the terms and conditions set forth in the Declaration of
      Registration rights attached hereto as Exhibit 5.1(d).

      2. THIRD PAYMENT.

            Triangle shall, on or before April 15, 2000, deliver 400,000 shares
of Triangle Common Stock (the "Third Payment") to the Escrow Agent of which that
number of shares to be reserved for the benefit of the holders of Assumed
Options and the holders of Assumed Warrants


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(the "Reserved Payment") shall be held by the Escrow Agent, and the remainder
shall be transferred promptly to the Exchange Agent for distribution to each of
the Former Avid Stockholders in proportion to the aggregate number of shares of
Parent Common Stock which such holder would otherwise be entitled to receive
from the aggregate of the First Payment, the Second Payment and the Third
Payment pursuant to Section 1.7 of the Agreement by virtue of such holder's
ownership of outstanding shares of Company Capital Stock immediately prior to
the Effective Time, and assuming for the purposes of such allocation that the
holders of all Assumed Options and the holders of all Assumed Warrants were the
holders of the number of shares of the Company Common Stock that would have been
issued had all of the Assumed Options and all of the Assumed Warrants been
exercised in full immediately prior to the Effective Time (assuming that the
exercise price was paid in cash). No later than seventy-five (75) days after
delivery to the Escrow Agent of an Agent Certificate, in form acceptable to
Triangle, pursuant to Section 1.7(d)(i) of the Agreement with respect to the
distribution of the Third Payment, the Third Payment less the Reserved Payment
shall be distributed from the Exchange Agent to the Former Avid Stockholders as
provided in such Agent Certificate. Triangle, the Escrow Agent, and the Exchange
Agent shall be entitled to rely without investigation on the accuracy of the
information set forth in such Agent Certificate.

      3. SECURITYHOLDER AGENT'S EXPENSES.

      Triangle shall pay the reasonable fees and expenses of legal counsel to
the Securityholder Agent incurred in connection with the drafting and review of
this Amendment and the transactions contemplated hereby and in communicating
with Former Avid Stockholders in connection therewith, subject to verification
of fees by Triangle.

      4. EFFECT OF AMENDMENT.

            Except as amended and set forth above, the Agreement shall continue
in full force and effect. In the event of any conflict between the terms of the
Agreement and the terms of this Amendment, the terms of this Amendment shall
govern and control. This Amendment shall become effective when executed and
delivered by Triangle, Avid and a majority of the individuals constituting the
Securityholder Agent.

      5. FURTHER ASSURANCES.

      The parties agree to execute such further instruments, agreement and
documents and to take such further action as may reasonably be necessary to
carry out the intent of this Amendment.

      6. COUNTERPARTS.

            This Amendment may be executed in any number of counterparts, each
which will be deemed an original, and all of which together shall constitute one
instrument.

      7. SEVERABILITY.

            If one or more provisions of this Amendment are held to be
unenforceable under applicable law, such provision shall be excluded from this
Amendment and the balance of the


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Amendment shall be interpreted as if such provision were so excluded and shall
be enforceable in accordance with its terms.

      8. GOVERNING LAW.

            This Amendment shall be governed by and construed under the laws of
the State of Delaware regardless of the laws that might otherwise govern under
applicable principles of conflicts of laws thereof.

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      This Amendment is hereby executed as of the date first above written.

TRIANGLE:                           TRIANGLE PHARMACEUTICALS, INC., a
                                    Delaware corporation

                                    By:    /s/ Chris A. Rallis
                                           -------------------------------------
                                    Name:  Chris A. Rallis
                                    Title: President and Chief Operating Officer


AVID:                               AVID CORPORATION, a Pennsylvania
                                    corporation

                                    By:    /s/ Chris A. Rallis
                                           -------------------------------------
                                    Name:  Chris A. Rallis
                                    Title: President


SECURITYHOLDER AGENT:


                                    --------------------------------------------
                                              Forrest H. Anthony


                                          /s/ Alan G. Walton
                                    --------------------------------------------
                                              Alan G. Walton


                                          /s/ Marcia T. Bates
                                    --------------------------------------------
                                              Marcia T. Bates

                   [SIGNATURE PAGE TO AMENDMENT NUMBER TWO TO
                    THE AGREEMENT AND PLAN OF REORGANIZATION]