Exhibit 10.43

              FIRST AMENDMENT TO THE JOINT SETTLEMENT AGREEMENT AND
    AGREEMENTS FOR RELEASE OF CLAIMS AND AMENDMENT OF PLAN OF REORGANIZATION

      FIRST AMENDMENT TO THE JOINT SETTLEMENT AGREEMENT AND AGREEMENTS FOR
RELEASE OF CLAIMS AND AMENDMENT OF PLAN OF REORGANIZATION (this "Amendment")
dated as of August [__], 2003 among GENSCI ORTHOBIOLOGICS, INC. ("Ortho") and
GENSCI REGENERATION SCIENCES, INC. ("Regeneration" and together with Ortho,
"GenSci") and OSTEOTECH, INC. ("Osteotech").

      The parties hereto are parties to the Joint Settlement Agreement and
Agreements for Release of Claims and Amendment of Plan of Reorganization dated
as of May 29, 2003 (the "Settlement Agreement") and wish to amend the Settlement
Agreement in light of the June 3, 2003 announcement that GenSci and IsoTis S.A.
("IsoTis") signed a definitive merger agreement. Accordingly, the parties hereto
hereby agree as follows:

      Section 1. Definitions. Defined terms used but not defined herein shall
have the respective meanings ascribed to such terms in the Settlement Agreement.
The Settlement Agreement (including any amendments thereto) shall be construed
in accordance with the laws of the State of California without reference to any
internal conflicts of law provisions.

      Section 2. Amendments to Settlement Agreement. The Settlement Agreement
shall be amended as follows:

            (a) Paragraph 10 of the Settlement Agreement. Paragraph 10 of the
      Settlement Agreement shall be amended by deleting it in its entirety and
      replacing it with the following:

            "10. GenSci acknowledges that payments made to Osteotech pursuant to
      this Settlement Agreement are a contemporaneous exchange of consideration
      for damages resulting from GenSci's infringement of the `558 and `655
      patents, taking into account the risks of litigation, and shall not be
      construed as a reasonable royalty. For purposes of implementing this
      settlement, Osteotech shall be deemed to have an Allowed Undisputed
      Unsecured Claim of $7,500,000 plus interest to be paid under the terms of
      the Plan as follows:

            (a) In the event that the Plan of Arrangement of GenSci Regeneration
            Sciences, Inc. ("Regeneration") under the British Columbia Company
            Act implementing the terms of the Arrangement Agreement between
            Regeneration and IsoTis S.A. ("IsoTis")(the "Plan of Arrangement")

                  (1) is approved by the special resolution of the shareholders
                  of Regeneration;

                  (2) is approved by Final Order of the British Columbia Supreme
                  Court; and

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                  (3) a certified copy of the Final Order is filed with, and
                  accepted by, the British Colombia Registrar of Companies;

                        (A) No later than two (2) business days after the
                  effective date (the "Effective Date") of GenSci
                  OrthoBiologics, Inc.'s Plan, GenSci shall pay Osteotech the
                  sum of US$2,500,000 by wire transfer of such funds to an
                  account to be designated by Osteotech.

                        (B) In addition to the payment set forth in paragraph
                  10(a)(A) herein, GenSci shall pay or cause to be paid to
                  Osteotech the sum of US$5,000,000, to be paid in twenty (20)
                  consecutive calendar quarterly installments, each in the
                  amount of US$250,000; provided, however, that GenSci shall
                  have the right to prepay any outstanding amounts at any time.
                  The first quarter payment shall be made by the tenth day of
                  the first full quarter following the Effective Date and
                  thereafter the quarterly payments shall be made on or before
                  the first business day of the quarter. Additionally, with each
                  quarterly payment described herein, GenSci shall pay accrued
                  interest at the federal judgment rate (up to a cap of 3% per
                  annum), calculated at the rate in existence for the week
                  preceding the end of the quarter, on the portion of the
                  US$5,000,000 outstanding from time to time, commencing on the
                  Effective Date. If GenSci is in default of any payment due
                  under this paragraph, then Osteotech shall provide GenSci with
                  written notice of such default by facsimile, e-mail or
                  overnight courier to the address specified herein. Upon the
                  sending of that notice, GenSci shall have thirty (30) calendar
                  days to cure such default. If the default is not cured within
                  that period, Osteotech, without limiting its rights under
                  applicable law, shall have the right to accelerate all
                  payments then owed under this paragraph and as may be fully
                  set forth in the Plan, with all rights and remedies including
                  but not limited to 11 U.S.C. ss. 1112, and remedies related to
                  the drawing on a clean, irrevocable, standby letter of credit
                  as set forth in Paragraph 12 hereof.

            (b) In the event that the Plan of Arrangement

                (1) is not approved by the special resolution of the
shareholders of Regeneration; or

                (2) is not approved by Final Order of the British Columbia
                Supreme Court; or

                (3) a certified copy of the Final Order is not filed with, and
                accepted by, the British Colombia Registrar of Companies;

                        (A) no later than two (2) business days after the
                  Effective Date, GenSci shall pay Osteotech the sum of
                  US$1,000,000 by wire transfer of such funds to an account to
                  be designated by Osteotech.

                        (B) In addition to the payment set forth in paragraph
                  10(b)(A) herein, GenSci shall pay or cause to be paid to
                  Osteotech the sum of US$6,500,000, to be paid in twenty (20)
                  consecutive calendar quarterly installments, each in the
                  amount of US$325,000; provided, however, that GenSci shall
                  have the right to prepay any


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                  outstanding amounts at any time. The first quarter payment
                  shall be made by the tenth day of the first full quarter
                  following the Effective Date and thereafter the quarterly
                  payments shall be made on or before the first business day of
                  the quarter. Additionally, with each quarterly payment
                  described herein, GenSci shall pay accrued interest at the
                  federal judgment rate (up to a cap of 3% per annum),
                  calculated at the rate in existence for the week preceding the
                  end of the quarter, on the portion of the US$6,500,000
                  outstanding from time to time, commencing on the Effective
                  Date. If GenSci is in default of any payment due under this
                  paragraph, then Osteotech shall provide GenSci with written
                  notice of such default by facsimile, e-mail or overnight
                  courier to the address specified herein. Upon the sending of
                  that notice, GenSci shall have thirty (30) calendar days to
                  cure such default. If the default is not cured within that
                  period, Osteotech, without limiting its rights under
                  applicable law, shall have the right to accelerate all
                  payments then owed under this paragraph and as may be fully
                  set forth in the Plan, with all rights and remedies including
                  but not limited to 11 U.S.C. ss. 1112, and remedies related to
                  the drawing on a clean, irrevocable, standby letter of credit
                  as set forth in Paragraph 12 hereof."

            (b) Paragraph 11 of the Settlement Agreement. Paragraph 11 of the
      Settlement Agreement shall be amended by deleting it in its entirety and
      replacing it as follows:

            "11. The obligations to Osteotech under Paragraph 10 herein, shall
      be evidenced by, and shall be subject to the terms and conditions of the
      Plan and as set forth in a promissory note in the form of Exhibit B hereto
      (the "Promissory Note") in the principal amount of: (i) US $5,000,000 in
      the event the conditions set forth in paragraph 10(a) are satisfied or
      (ii) US $6,500,000 otherwise, with such Promissory Note being executed by
      GenSci in favor of Osteotech and delivered on or before two (2) days after
      the Effective Date. Forthwith upon the payment in full by GenSci to
      Osteotech of US $5,000,000 or US $6,500,000 plus accrued interest
      calculated in accordance with paragraph 10, Osteotech shall return the
      Promissory Note to GenSci for cancellation, shall execute all documents
      permitting the cancellation of the Letter of Credit without its being
      drawn down and shall execute all documents to terminate the Security
      Agreement, if any."

            (c) Paragraph 12 of the Settlement Agreement. Paragraph 12 of the
      Settlement Agreement shall be amended by (i) deleting from the first
      sentence the language " or an irrevocable escrow agreement satisfactory to
      Osteotech (the "Escrow Agreement")"; (ii) adding the following language to
      the end of the first sentence: "provided, however, that the Letter of
      Credit shall reduce in principal amount after the most recent quarterly
      payment has been made and becomes final and not subject to avoidance, to
      reflect the most current amount owed by GenSci." and (iii) deleting the
      second sentence thereof in its entirety and replacing it with the
      following:

            "In the event of default and acceleration pursuant to Paragraph 10
      herein, and as amplified by the Plan, or if the Letter of Credit is not
      renewed or expires prior to Osteotech's receipt of all sums due pursuant
      to Paragraph 10 herein, Osteotech shall have the right to present a sight
      draft on the Letter of Credit in the aggregate accelerated


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      amount upon presentation of an officer's certificate stating that an event
      of default has occurred and the time for any cure has elapsed. The Parties
      agree that amounts provided as security for the Letter of Credit do not
      constitute property of the GenSci estates as defined in 11 U.S.C. ss.
      541."

            (d) Paragraph 13 of the Settlement Agreement. Paragraph 13 of the
      Settlement Agreement shall be amended by deleting the first sentence
      thereof in its entirely and replacing it with the following:

            "In the event the conditions set forth in Paragraph 10(a) are
      satisfied, Paragraph 13 shall have no force or effect. However, in the
      event that the Plan of Arrangement

            (a)   is not approved by the special resolution of the shareholders
                  of Regeneration; or

            (b)   is not approved by Final Order of the British Columbia Supreme
                  Court; or

            (c)   a certified copy of the Final Order is not filed with, and
                  accepted by, the British Colombia Registrar of Companies,

      in addition to the Letter of Credit in the amount of US $5,000,000, GenSci
      shall secure the remaining balance of US$1,500,000 due to Osteotech
      pursuant to Paragraph 10(b) herein by delivering to Osteotech as a part of
      the Plan on or before the Effective Date a Security Agreement in the form
      of Exhibit C hereto (the "Security Agreement"), pursuant to which GenSci
      grants Osteotech an attached and perfected security interest to secure the
      balance of US$1,500,000, in all personal property of GenSci, including but
      not limited to all now existing or after acquired accounts, inventory,
      equipment, general intangibles and intellectual property."

            (e) Paragraph 16 of the Settlement Agreement. Paragraph 16 of the
      Settlement Agreement shall be amended by deleting subparagraph (ii)
      thereof in its entirety and replacing it with the following:

            "(ii) use its reasonable best efforts to obtain confirmation of the
      Plan as promptly as practicable, and in any event no later than December
      31, 2003, or such later date as may be approved by Osteotech, which
      approval shall not be unreasonably withheld, and proceed diligently to
      obtain the dismissal of all appeals, applications and motions for
      reconsideration with respect to the disclosure statement, Plan, other
      order or ruling or order confirming the plan, as promptly as practicable."

            (f) Paragraph 23 of the Settlement Agreement. Paragraph 23 of the
      Settlement Agreement shall be amended by deleting it in its entirety and
      replacing it with the following:

            "23. GenSci shall have the right to assign or transfer any of its
      rights and obligations under this Settlement Agreement (including without
      limitation, its rights under Paragraph 19 of this Settlement Agreement)
      provided that the assignee assumes all of GenSci's obligations under this
      Settlement Agreement. GenSci shall remain liable for


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      its obligations under this Settlement Agreement, and the issuer of any
      Letter of Credit shall remain liable for its obligations under the Letter
      of Credit, notwithstanding any such assignment. All rights and benefits of
      GenSci under this Settlement Agreement (including Paragraph 19 hereto)
      will remain vested in GenSci following the consummation of the Plan of
      Arrangement and the change in control of GenSci (without the necessity of
      delivering an assumption agreement in connection with this Paragraph 23 of
      this Settlement Agreement) and all such rights and benefits may be
      assigned to a third party, provided the requirements set forth in this
      paragraph are satisfied."

            (g) New Paragraph 28 of the Settlement Agreement. The Settlement
      Agreement shall be amended by adding a new Paragraph 28 which shall state
      as follows:

            "28. GenSci agrees that it will not amend the Arrangement Agreement
      between Regeneration and IsoTis:

            (a)   with respect to the Effective Date or the Termination Date (as
                  those terms are used in the Arrangement Agreement); or

            (b)   to adversely impact upon the obligations of IsoTis contained
                  in Sections 6.8 and 7.14 of the Arrangement Agreement

      without the prior approval of Osteotech, which approval shall not be
      unreasonably withheld. Osteotech shall have two (2) business days to
      consider such amendment(s) and, absent GenSci's receipt of written
      objections within such two-day period, shall be deemed to consent to such
      amendment. GenSci further agrees that it shall not agree to any other
      revisions or amendments to the Arrangement Agreement or to the Plan of
      Arrangement without first providing a copy of such proposed revisions or
      amendments to Osteotech at least two (2) business days prior to such
      amendments or revisions becoming operative."

            (h) New Paragraph 29 of the Settlement Agreement. The Settlement
      Agreement shall be amended by adding a new Paragraph 29 which shall state
      as follows:

            "Osteotech will agree to the entry of an order of dismissal of the
      Regeneration Chapter 11 Case, provided, however, that such order shall be
      subject to revocation in the event that the Plan of Arrangement:

                  (a) is not approved by the special resolution of the
                  shareholders of Regeneration; or

                  (b) is not approved by Final Order of the British Columbia
                  Supreme Court; or

                  (c) a certified copy of the Final Order is not filed with, and
                  accepted by, the British Colombia Registrar of Companies.


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                  Furthermore, so long as Osteotech receives the treatment under
                  GenSci OrthoBiologics, Inc.'s Plan as provided for in the
                  Settlement Agreement (including any subsequent amendments),
                  Osteotech shall support such Plan and any disclosure statement
                  filed in connection with such Plan."

            (i) New Paragraph 30 of the Settlement Agreement. The Settlement
      Agreement shall be amended by adding a new Paragraph 30 which shall state
      as follows:

            "The Parties agree to reserve their respective rights with regard to
      the disposition of funds held by GenSci pursuant to the Bankruptcy Court's
      May 17, 2002 Order."

            Section 3. Settlement Agreement Otherwise Unchanged. Except as
      amended herein, the Settlement Agreement shall remain unchanged and in
      full force and effect and its provisions are hereby confirmed and
      ratified.

            Section 4. Counterparts. This Amendment may be executed in any
      number of counterparts, each of which shall be identical and all of which,
      when taken together, shall constitute one and the same instrument, and any
      of the parties hereto may execute this Amendment by signing any such
      counterpart.

            Section 5. Binding Effect. This Amendment shall be binding upon and
      inure to the benefit of the parties hereto and their respective successors
      and assigns.

            IN WITNESS WHEREOF, the parties hereto have caused this Amendment to
      be duly executed as of the day and year first above written.

OSTEOTECH, INC.                              GENSCI ORTHOBIOLOGICS, INC.



By: /s/ Michael J. Jeffries                  By:  /s/ Douglas C. Watson
   ---------------------------                  -----------------------------
Name:  Michael J. Jeffries                   Name:  Douglas C. Watson
Title: Exec. Vice Pres, CFO                  Title: CEO & President

Date: 8/21/03                                Date: 8/16/03

                                             GENSCI REGENERATION SCIENCES, INC.



                                             By:  /s/ Douglas C. Watson
                                                -----------------------------
                                             Name: Douglas C. Watson
                                             Title: CEO & President

                                             Date: 8/16/03


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