Exhibit 10.1


Confidential
materials omitted and filed separately with the Securities and Exchange

Commission.  Asterisks denote such
omission.


AGREEMENT REGARDING

VALIDATION CAMPAIGN


This AGREEMENT REGARDING
VALIDATION CAMPAIGN (“Agreement”), dated effective as of July 1, 2006 (the “Effective
Date”), is entered into by and between Genzyme Corporation, a
Massachusetts corporation with its principal office at 500 Kendall Street,
Cambridge, MA  02142 (“Genzyme”), Dyax
Corp., a Delaware corporation with its principal office at 300 Technology
Square, Cambridge, Massachusetts 02139 (“Dyax”) and Dyax-Genzyme LLC, a
Delaware limited liability company with its principal office at 300 Technology
Square, Cambridge, Massachusetts 02139 (“Dyax-Genzyme LLC”).


WHEREAS, Dyax and Genzyme are parties to an Amended
and Restated Collaboration Agreement, dated as of May 31, 2002,  as amended to date (the “Collaboration
Agreement”);


WHEREAS, under the terms of the Collaboration
Agreement, Dyax and Genzyme are jointly developing a 58-amino acid polypeptide
human plasma kallikrein inhibitor, known as DX-88;


WHEREAS, to manage the development of DX-88, Dyax and
Genzyme formed Dyax-Genzyme LLC as a jointly owned limited liability company;


WHEREAS, under the terms of the Collaboration Agreement,
Dyax and Genzyme are responsible for all costs associated with the development
of DX-88 in accordance with Section 4.3.2 of the Collaboration Agreement;


WHEREAS, as authorized by Dyax-Genzyme LLC under the
terms of the Collaboration Agreement, Dyax has entered into an agreement, dated
March 15, 2006, with Avecia Limited (the “Validation Campaign Agreement”, under
which Avecia will (i) carry out the manufacture of one development batch and
three sequential batches of DX-88 drug substance at 5,000 liter scale, and (ii)
provide Dyax with additional support necessary in connection with the filing
for BLA / MAA approval for DX-88;


WHEREAS, the expenses incurred by Dyax in connection
with the activities conducted under the Validation Campaign Agreement would be
considered Program Costs (as defined under the Collaboration Agreement),
subject to reimbursement as provided under the terms of the Collaboration
Agreement;


WHEREAS, Dyax wishes to own and control, independent
of its obligations under the Collaboration Agreement, the DX-88 drug substance
manufactured by Avecia under the Validation Campaign Agreement; and


WHEREAS, Genzyme is willing to allow Dyax to own and
control such DX-88 drug substance, subject to the terms and conditions set
forth herein.


NOW, THEREFORE, in consideration of the promises and
agreements set forth herein, and for other good and valuable consideration, the
receipt and sufficiency of which are hereby acknowledged, Genzyme and Dyax
hereby agree as follows:


1.             Defined Terms.   All capitalized terms not defined in this
agreement shall have the meaning given to them in the Collaboration Agreement.









 



 


2.             Assumption of Manufacturing Expenses.   Attached as Exhibit A hereto is
the currently approved budget highlighting the expenses that are scheduled to
be incurred in connection with the activities conducted under the Validation
Campaign Agreement.   In consideration
for rights granted to Dyax under Section 3 below to own and control the DX-88
drug substance manufactured by Avecia under the Validation Campaign Agreement
(the “DX-88 API”), Dyax hereby agrees that it will assume full responsibility
for all expenses incurred by Dyax in connection with the production of DX-88
API under the Validation Campaign Agreement, including without limitation activities
through other third party contractors (e.g. Formatech), up to Fourteen Million Five
Hundred Thousand United States Dollars (U.S.$14,500,000) (the “Manufacturing
Expense Limit”).  For the avoidance of
doubt, the parties acknowledge and agree that (i) Dyax shall not be able to
seek reimbursement, under the Collaboration Agreement or otherwise, for any
costs incurred for the production of DX-88 API under the Validation Campaign
Agreement until the Manufacturing Expense Limit has been achieved, and (ii)
upon achievement of the Manufacturing Expense Limit, all remaining expenses
incurred in connection with the production of DX-88 API  under the Validation Campaign Agreement will
be considered Program Costs subject to reimbursement in accordance with Section
4.3.3 of the Collaboration Agreement.


3.             Ownership of Drug Product.   Dyax shall own and control,
independent of any obligations under the Collaboration Agreement, any and all
of the DX-88 API until the achievement of the Manufacturing Expense Limit.  Thereafter, the DX-88 API shall be owned and
controlled by each of Dyax and Dyax-Genzyme LLC as calculated in accordance
with the following formulas:


DX-88 API owned and controlled by Dyax:                                                    B/A
* D


DX-88 API owned and controlled by Dyax-Genzyme LLC:                           C/A * D


	
  

  	
  Where:

  	
  A

  	
   

  	
  =

  	
   

  	
  Total manufacturing costs incurred in the production
  of DX-88 API under the Validation Campaign Agreement;

  
	
   

  	
   

  	
   

  	
   

  	
   

  	
   

  	
   

  
	
   

  	
   

  	
  B

  	
   

  	
  =

  	
   

  	
  Total manufacturing costs incurred in the production
  of DX-88 API under the Validation Campaign Agreement paid by Dyax, which
  shall be the Manufacturing Expense Limit of $14,500,000;

  
	
   

  	
   

  	
   

  	
   

  	
   

  	
   

  	
   

  
	
   

  	
   

  	
  C

  	
   

  	
  =

  	
   

  	
  Total manufacturing costs incurred in the production
  of DX-88 API under the Validation Campaign Agreement paid by Dyax-Genzyme LLC
  (computed as A-B); and

  
	
   

  	
   

  	
   

  	
   

  	
   

  	
   

  	
   

  
	
   

  	
   

  	
  D

  	
   

  	
  =

  	
   

  	
  Total Mgs of DX-88 API manufactured by Avecia.

  



 


For
the avoidance of
doubt, the parties acknowledge and agree that such DX-88 API owned and
controlled by Dyax may be (i) used by Dyax in the development or
commercialization of DX-88 as a Surgical Product or any other indication now or
in the future that is owned by Dyax independent of its collaboration with
Genzyme, or (ii) supplied to Dyax-Genzyme LLC, on the terms set forth in
Section 4 below, for use in the development or commercialization of DX-88 as a
Collaboration Product. 


Furthermore,
the parties acknowledge and agree that any and all DX-88 API that is necessary
to be used for validation, stability, and other analytical studies that are
conducted on behalf of Dyax-Genzyme LLC in connection with 


 


Confidential materials omitted and
filed separately with the Securities and Exchange

Commission.  Asterisks denote such
omission.



 2
 






 



 


the Validation Campaign
Agreement or for marketing approval of DX-88 will be taken from the DX-88 API
owned and controlled by Dyax-Genzyme LLC.


4.             Sale of DX-88 API to Dyax-Genzyme LLC. 
Dyax-Genzyme LLC may from time to time request, at its sole option, that
Dyax sell the DX-88 API to Dyax-Genzyme LLC for use in the development or
commercialization of DX-88 as a Collaboration Product.  Dyax may, at its option, accept or reject any
such request.  If such request is
accepted by Dyax, the DX-88 API will be supplied to Dyax-Genzyme LLC at a price
per mg calculated as follows:


	
  

  	
  Price per mg

  	
   

  	
   

  	
  =

  	
   

  	
  A/B      *      ( (1+C)   *   D/12 )

  
	
   

  	
   

  	
   

  	
   

  	
   

  	
   

  	
   

  
	
  

  	
  where:

  	
  A

  	
   

  	
  =

  	
   

  	
  all expenses incurred in
  connection with the activities conducted under the Validation Campaign
  Agreement that were assumed by Dyax under Section 2 above, up to the
  Manufacturing Expense Limit;

  
	
   

  	
   

  	
   

  	
   

  	
   

  	
   

  	
   

  
	
   

  	
   

  	
  B

  	
   

  	
  =

  	
   

  	
  the total number of mgs of
  DX-88 API manufactured under the Validation Campaign Agreement, and owned and
  controlled by Dyax;

  
	
   

  	
   

  	
   

  	
   

  	
   

  	
   

  	
   

  
	
   

  	
   

  	
  C

  	
   

  	
  =

  	
   

  	
  Dyax’s cost of financing,
  determined for the purposes of this Agreement to be *****************,
  compounded monthly; and

  
	
   

  	
   

  	
   

  	
   

  	
   

  	
   

  	
   

  
	
   

  	
   

  	
  D

  	
   

  	
  =

  	
   

  	
  the number of complete
  calendar months that have occurred between the date of the request for DX-88
  API by Dyax-Genzyme LLC and December 31, 2006.

  



 


Furthermore, if and when DX-88 receives marketing approval in the United
States or the European Union, Dyax-Genzyme LLC shall be obligated to request
that Dyax supply DX-88 API to Dyax-Genzyme LLC in an amount determined solely
by Dyax-Genzyme LLC at the price set forth above and Dyax shall accept such
request.  Such obligation is intended to
mean that following marketing approval in the United States or the European
Union, if and when DX-88 drug substance is needed for commercial sale or
otherwise, Dyax-Genzyme LLC must request, in preference to all available
sources other than quantities owned and controlled by Dyax-Genzyme LLC, that
such DX-88 drug substance be supplied by Dyax at the price set forth above.


For the avoidance of doubt, drug substance supplied by Dyax to
Dyax-Genzyme LLC will only be DX-88 API and Dyax-Genzyme LLC will always take
title to such DX-88 API prior to any fill/finish activities.  All fill/finish activities and expenses will
be the sole responsibility of Dyax-Genzyme LLC.


 


Confidential
materials omitted and filed separately with the Securities and Exchange

Commission.  Asterisks denote such
omission.



 3
 






 



 


IN WITNESS WHEREOF, the parties hereto have caused
this Agreement to be executed by their respective duly authorized representatives,
under seal, as of the Effective Date hereof.


	
  GENZYME CORPORATION

  	
   

  	
   

  	
  DYAX CORP.

  
	
   

  	
   

  	
   

  	
   

  	
   

  	
   

  
	
  By: 

  	
  /s/ Georges Gemayel

  	
   

  	
   

  	
  By:

  	
  /s/ Thomas R. Beck

  
	
  Name:

  	
  Georges Gemayel

  	
   

  	
   

  	
  Name:

  	
  Thomas R. Beck

  
	
  Title:

  	
  Executive Vice President

  	
   

  	
   

  	
  Title:

  	
  President and Chief Operating Officer

  



 


DYAX-GENZYME LLC


DYAX
CORP., MEMBER:


	
  By:

  	
  /s/ Thomas R. Beck

  	
   

  
	
  Name:

  	
  Thomas R. Beck

  	
   

  
	
  Title:

  	
  President and Chief Operating Officer

  	
   

  
	
   

  	
   

  	
   

  
	
  GENZYME CORPORATION, MEMBER:

  	
   

  
	
   

  	
   

  	
   

  
	
  By:

  	
  /s/ Georges Gemayel

  	
   

  
	
  Name:

  	
  Georges Gemayel

  	
   

  
	
  Title:

  	
  Executive Vice President

  	
   

  



 


Confidential
materials omitted and filed separately with the Securities and Exchange

Commission.  Asterisks denote such
omission.



 4














 


 


EXHIBIT A

TO

AGREEMENT REGARDING

VALIDATION
CAMPAIGN


VALIDATION CAMPAIGN BUDGETED EXPENSES


*****************


 


 


 


 


Confidential
materials omitted and filed separately with the Securities and Exchange

Commission.  Asterisks denote such
omission.