EXHIBIT 10.64


                               AGREEMENT TO AMEND
                         SECURITIES PURCHASE AGREEMENT
                         AND CERTAIN RELATED SECURITIES

     This Agreement (the  "Agreement")  is made as of June 30, 1999 by and among
(a) Bioject Medical  Technologies Inc., an Oregon corporation  ("Bioject"),  (b)
Elan  International  Services,  Ltd.,  a Bermuda  corporation  ("EIS"),  and (c)
Marathon Medical  Technologies,  Inc., an Oregon corporation  ("Marathon");  and
amends that certain  Securities  Purchase Agreement dated as of October 15, 1997
(as  amended at any time,  the  "Securities  Purchase  Agreement")  and  certain
related securities.


                                    RECITALS

     A. Bioject and EIS are parties to the  Securities  Purchase  Agreement  and
related documents with respect to the creation and funding of Marathon, which is
a joint venture company established to develop,  manufacture and market products
relating  to  certain  glucose   monitoring   technologies   developed  by  Elan
Corporation,  plc,  an Irish  public  limited  company and an  affiliate  of EIS
("Elan";  such technologies,  collectively,  the  "Technology").  After the date
hereof,  the parties  intend that Marathon  license the  Technology to a certain
unaffiliated company or companies.

     B. Bioject and EIS desire to set forth herein certain  provisions  relating
to  Marathon,  and,  in  connection  therewith,  to amend the  terms of  certain
existing arrangements between EIS and Bioject.

     C. All terms used but not defined  herein shall have the meanings  ascribed
to them in the Securities Purchase Agreement.


                                    AGREEMENT

     NOW, THEREFORE, Bioject and EIS hereby agree as follows:

     1.  Series  A  Preferred  Stock.  The  Securities  Purchase  Agreement  and
Bioject's  Articles of  Amendment to the  Articles of  Incorporation  (including
Section 6(a)(1)  thereof) shall be amended,  from and after the date hereof,  to
provide  that the  conversion  price of the Series A  Preferred  Stock  shall be
$1.50,  subject to adjustment as provided  therein,  rather than the  conversion
price originally set forth therein.

     In addition,  a new sentence shall be added to the end of such section,  as
follows:  "In the event that any holder shall provide notice to the  Corporation
of its intention to convert such holder's shares of Series A Preferred Stock, as
provided above, the Corporation shall have the right,  within 90 days of receipt
of such notice and upon







five business days' notice to the holders,  to cause to be redeemed for cash the
shares of Series A Preferred  Stock subject to such notice,  at a price equal to
aggregate  purchase  price  for such  shares of Series A  Preferred  Stock  plus
mandatory  dividends  thereon at a rate equal to 9% per annum,  from the date of
issuance  until the date redeemed in full. In the event that such cash amount is
not paid within such 90-day period,  such redemption right shall lapse and be of
no further force and effect, and the holders shall thereupon have the right once
again to convert  such  shares of Series A  Preferred  Stock into  shares of the
Corporation's Common Stock. During such 90-day (or shorter, if redeemed,  as set
forth above) period,  the holders of Series A Preferred  Stock shall not convert
such stock into the Corporation's  Common Stock,  whether or not the Corporation
exercises its right of redemption."

     Bioject  covenants that it shall request and use its best efforts to obtain
shareholder  approval  of the  amendment  to its  Articles of  Incorporation  in
accordance  with this Section 1 at its next annual  meeting of  shareholders  in
September 1999. Bioject represents to EIS that the board of directors of Bioject
has recommended or will recommend to the  shareholders of Bioject that they vote
in favor of such  amendment.  EIS agrees that it shall vote all of its shares of
Bioject's  capital  stock,  to the extent such shares are entitled to vote,  for
such amendment.

     2. Series B Preferred  Stock. (a) EIS shall on the date hereof exchange all
of its  shares of Series B  Preferred  Stock for a  warrant  to  purchase  up to
3,790,000  shares  of  Common  Stock of  Bioject;  such  warrant  is in the form
attached  hereto as Exhibit A, and it shall be executed and delivered by Bioject
to EIS on the date hereof. From and after the date hereof, all of such shares of
Series B Preferred Stock shall be canceled and of no further force and effect.

     3. Termination of Rights and Obligations. As of the date hereof, the rights
and  obligations of EIS with respect to Recital D, Section 1(d) and Section 5(d)
of the Securities  Purchase Agreement shall terminate and be of no further force
and effect.

     4.  Certain  Provisions  Relating  to  Marathon.  (a) EIS hereby  sells and
delivers  to Bioject  all of EIS's  right,  title and  interest in and to all of
EIS's shares of common stock of Marathon, consisting of 238,800 shares of common
stock, for the Purchase Price (as defined in Section 4(d)). In that regard,  EIS
shall  expeditiously  cause to be delivered to Bioject share certificates and/or
stock powers in blank and duly endorsed,  to effect such  transfer.  Each of EIS
and Marathon agrees that, as between themselves, from and after the date hereof,
the Newco Subscription and Stockholders  Agreement dated as of October 15, 1997,
as amended, is terminated and of no further force and effect.

     (b) Each of EIS and  Bioject  represents  and  warrants  to the other party
that, other than as previously  disclosed to the other party, it is not aware of
any liability or obligation of Marathon.



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     (c) Each of Bioject and Marathon agrees,  jointly and severally,  to assume
and be liable for all of the  obligations  and  liabilities  of Marathon and its
business,  from and after the date  hereof,  and each of  Bioject  and  Marathon
hereby  releases and holds  harmless EIS, Elan and their  respective  affiliates
from and against  any and all  liabilities  or  obligations,  including  without
limitation, any and all liabilities and obligations relating to Marathon and the
business  of  Marathon,  from  the  commencement  of its  business  through  and
including the date hereof.

     (d) As soon as practical after the date hereof,  Marathon shall cause to be
paid out of the License Fee (as defined below),  all unpaid accounts  payable of
Marathon arising on or before the date hereof,  excluding any employment-related
accounts payable (the "Payables").  Such amount shall include accrued and unpaid
inter-company  accounts  payable owing to Bioject and Elan in respect of certain
goods  and/or  services  previously  provided by Bioject  and Elan to  Marathon,
except  that  such  amounts  owing to Elan  shall be  reduced  by the sum of all
markups on research  and  development  costs  invoiced to Bioject for the months
since March 1999 and by an  additional  $100,000.  The final cash  payment  (the
"Purchase  Price") to EIS for its shares of Marathon's common stock shall be the
product of (a) the License Fee less (i) the Payables and (ii) $100,000,  and (b)
19.9%, less $200,000, as set forth below:

     The Purchase  Price = ((License  Fee - the (a) Payables and (b) $100,000) *
     19.9%) - $200,000

An  illustration  of the calculation of the Purchase Price and other payments is
set forth on Schedule 1 hereto; such schedule also sets forth an illustration of
the  reconciliation  of the outstanding  liabilities and obligations of Marathon
and the payment of funds to be received by Marathon, to each of Bioject and EIS,
respectively.  The parties acknowledge that the amounts described above shall be
disbursed  from the  proceeds to Marathon of a license of the  Technology  to an
unaffiliated third party on the date hereof.

     (e) Marathon and Bioject shall, prior to Marathon's liquidation as provided
in Section 4(f) below,  cause to be licensed,  on customary terms and conditions
that are reasonably  satisfactory to EIS, the  Technologies,  to an unaffiliated
third party  previously  disclosed  to EIS and  Marathon;  in that  regard,  the
parties acknowledge that Marathon shall receive, among other things, an up-front
license fee of $4 million (the "License Fee").

     (f) It is the  intention  of the  parties to  liquidate  and to wind up the
business  of  Marathon,  and to cause  Marathon's  assets to be  distributed  to
Bioject and cause Bioject to assume Marathon's liabilities.  Each of Bioject and
Marathon  covenants (x) to effect such actions as soon as practicable  after the
date hereof (after giving  effect to the other actions  described  above in this
Section 4) and (y) to ensure, to the greatest extent  practicable,  that neither
EIS  nor  any of its  affiliates  shall  have  any  liabilities  or  obligations
(including tax or regulatory filing obligations  relating only to the operations
of Marathon) in connection therewith. In connection with the foregoing,  Bioject
agrees that it shall indemnify and hold harmless EIS, Elan and their  respective
affiliates from



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and against  any and all  liabilities  of,  incurred by or related in any way to
Marathon or the business of Marathon  from and after the date hereof  (excluding
all taxes,  including  withholding  obligations,  imposed with respect to EIS or
Elan in connection with the transactions contemplated hereby).

     5. Further  Assurances.  Each party  covenants that from and after the date
hereof it shall  take all  reasonable  actions  (including  any and all  actions
necessary to cause the prompt  resignation of the directors of Marathon from its
board of  directors)  and  execute and deliver  any  appropriate  documents  and
instruments to implement or better assure to the other parties the  transactions
described herein and/or the benefits intended to afforded hereby.

     6. Disclosure. The parties agree that prior to issuing any press release or
making any public disclosure of the transactions contemplated hereby, each party
shall obtain the approval of the others to the text and contents thereof,  which
approval shall not be  unreasonably  withheld or delayed;  it being  understood,
that since each party may be obligated to make such disclosures as it determines
in good faith are required by applicable law,  including  applicable  securities
laws, the other party shall respond to any such request by the requesting  party
within one business day of any such request.

     7.  Miscellaneous.  This  Agreement  shall be governed by and  construed in
accordance  with the laws of the State of New  York,  without  giving  effect to
principles  of  conflicts  of laws,  and shall be binding  upon and inure to the
benefit of the parties  hereto and their  respective  successors  and  permitted
assigns.  Any dispute  arising  hereunder shall be adjudicated in any federal or
state  court  sitting in the county,  city and state of New York.  Except as set
forth above, the Securities  Purchase Agreement and the other documents executed
in  connection  therewith  shall  remain in full force and effect as  originally
stated therein or as amended at any time.  This Agreement may be executed in any
number  of  counterparts,  and each  such  counterpart  shall be deemed to be an
original  instrument,  but all such  counterparts  together shall constitute one
agreement.  This Agreement shall be binding upon and inure to the benefit of the
parties' respective successors and assigns.






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     IN  WITNESS  WHEREOF,  each  of the  undersigned  has  duly  executed  this
Agreement as of the date first written above.


                                  BIOJECT MEDICAL TECHNOLOGIES INC.


                                  By: ------------------------------------------
                                       Name:
                                       Title:


                                  MARATHON MEDICAL TECHNOLOGIES, INC.


                                  By: ------------------------------------------
                                       Name:
                                       Title:


                                  ELAN INTERNATIONAL SERVICES, LTD.


                                  By: ------------------------------------------
                                       Name:
                                       Title: