##### 



EXHIBIT 2.3
 CONFIDENTIAL
MATERIAL OMITTED AND
FILED SEPARATELY WITH THE SECURITIES
AND EXCHANGE COMMISSION.
ASTERISKS DENOTE SUCH OMISSIONS.
 Collaboration and License Agreement
 Agreement Execution
Date Jerini US, Inc.  Jerini Kos Life Sciences, Inc.  Delaware Kos Party Parties
 Recitals
 A.
 B.
 C.
 D.
 E.
  Agreement
 1. Definitions
  1.1 Additional Formulation Product
 1.2 Affiliate
 1




---



##### 



provided
 1.3 Angioedema Field
 1.4 Assigned Invention solely
 1.5 Asthma Field
 1.6 Aventis Agreement
 1.7 Bachem Manufacturing Agreement
 1.8 Blocking Patent
 1.9 Business Day
 1.10 Commercialization Commercialize
 1.11 Commercially Reasonable Efforts
 2




---



##### 



1.12 Committee
 1.13 Confidential Information
 1.14 Controlled Control
 1.15 Development Plan
 1.16 Development Program
 1.17 Effective Date
 1.18 FDA
 1.19 First Commercial Sale
 1.20 FTE
 1.21 GAAP
 1.22 GCP
 3




---



##### 



1.23 GLP
 1.24 Growth Rate Goal
 1.25 HSR Act
 1.26 Icatibant
 1.27 Jerini House Marks
 1.28 Jerini Invention
 1.29 Jerini R/A Product
 1.30 Know-How
 1.31 Kos House Marks
 1.32 Kos Invention
 4




---



##### 



1.33 Licensed Field
 1.34 Licensed Know-How
 1.35 Licensed Patents Exhibit A Aventis Patents
 1.36 Licensed Product
 1.37 Licensed Technology
 1.38 MAA
 1.39 Marketing Approval
  1.40 Marketing Plan
 1.41 NDA
 1.42 Net Sales
 5




---



##### 



1.43 Patents
 1.44 Phase I Clinical Trial
 1.45 Phase II Clinical Trial
 1.46 Phase III Clinical Trial
 1.47 Phase IV Clinical Trial
 1.48 Product Trademarks
 1.49 Promotional Materials
 1.50 RAIL Field
 1.51 R/A Field
 1.52 Sanofi-Aventis
 6




---



##### 



1.53 Sublicense Agreement
 1.54 Sublicensee
 1.55 Term
 1.56 Territory
 1.57 Third Party
 1.58 Third Party Technology
 1.59 United States
 1.60 Valid Claim
 1.61 Wülfing Manufacturing Agreement
 2.
    
    Management of Collaboration
 2.1 General
 2.2 Joint Steering Committee JSC
 7




---



##### 



2.3 Joint Development Committee JDC
 2.4 Joint Commercialization Committee JCC
 2.5 Membership and Procedures
 2.5.1 Membership.
 2.5.2 Chairpersons.
 2.5.3 Meetings.
 (a)
 8




---



##### 



provided
 (b) provided
 (c) provided
 2.5.4 Limitations of Powers
 2.6 Decision-Making
 2.6.1 Disagreement
 2.6.2 Notice of Disagreement
 2.6.3
 9




---



##### 



(a)
 (b)
 2.6.4
 2.6.5
 3. Development of Licensed Product
 3.1 Development Program
 3.1.1 Development Plan
 (a) Development Plan Exhibit B
 (b)
 3.1.2 Performance provided


10



---



##### 



3.1.3 Records.
 3.1.4 Expenses.
 (a)
 (b)
 3.2 Progress Reports.
 3.3 Diligence.
 3.3.1 Angioedema Field
 3.3.2 R/A Field
 (a)
 (b)
 11




---



##### 



provided further provided
 (c) provided further provided
 (d)
 3.4 Third Party Technology
 3.4.1 Obtained by Jerini provided
 3.4.2 Obtained by Kos
 12




---



##### 



provided
 3.4.3 Blocking Patents
 4. Regulatory Matters
 4.1 Responsibility for Regulatory Affairs
 4.1.1 Angioedema Field
 (a)
 (b) provided
 4.1.2 R/A Field
 (a)
 (b)
 13




---



##### 



provided
 4.2 Access, Use and Reference Rights to Data and Filings
 4.2.1 Access to Data.
 4.2.2 Grant by Jerini
 4.2.3 Grant by Kos
 14




---



##### 



4.3 Correspondence and Meetings with Regulatory Authorities.
 4.3.1
 4.3.2 Responsible Party
 4.4 Recalls and Withdrawals
 4.4.1
 4.4.2
 4.4.3
 4.4.4
 15




---



##### 



4.4.5
 4.5 Pharmacovigilance
 4.6 Regulatory Obligations during Commercialization
 4.6.1 Angioedema Field
 4.6.2 R/A Field
 4.7 HSR Act
 4.7.1
 16




---



##### 



FTC DOJ
 4.7.2
 5. Commercialization of Licensed Product
 5.1 Marketing Plans.
 5.1.1 Marketing Plan Exhibit C provided
 5.1.2
 5.2 Marketing Activities
 5.2.1
 17




---



##### 



5.2.2
 5.2.3
  5.2.4
 5.3 Performance.
 5.3.1
 5.3.2 provided
 5.4 Allocation of Commercialization Costs. * * *
 5.5 Branding; Trademarks; Trade Dress; Logos
 5.5.1 Designated Jerini Trademark
 5.5.2
 18




---



##### 



5.5.3
 5.5.4 ®
 5.5.5
 5.5.6
 5.5.7 provided
 19




---



##### 



5.5.8
 5.6 Reporting.
 5.7 Diligence in Commercialization
 5.8
 5.9 Provisions Applicable to Sales Representatives.
 5.9.1
 5.9.2 provided
 5.9.3 provided
 5.9.4
 20




---



##### 



5.10 Compliance with Laws.
 6.
 6.1 Manufacturing and Supply Agreement Supply Agreement Exhibit
G
 6.2 Manufacture and Supply in R/A Field
 7. Financial Terms
 7.1 Initial License Fee 
 7.2 Milestone Payments in Angioedema Field
 Hereditary Angioedema
 Milestone Event
    
    Milestone Payment1.
    
    
    Receipt of Marketing Approval for * * * which Marketing Approval
provides for an expiration dating period based on a shelf life of at
least * * * (whether such period is included in the initial Marketing
Approval or by a subsequent amendment)
    
    US$* * *
 21




---



##### 



Milestone Event
    
    Milestone Payment2a.
    
    
    If * * *, agreed to the development of an * * *:
    
    US$* * ** * *, which Marketing Approval provides for an expiration dating
period based on a shelf life of at least * * * (whether such period is
included in the initial Marketing Approval or by a subsequent
amendment)2b.
    
    
    * * * and provided that such Additional Formulation Product will have
* * * years of market exclusivity after the date of First Commercial
Sale in the United States:
    
    US$* * ** * *, which Marketing Approval provides for an expiration dating
period based on a shelf life of at least * * * (whether such period is
included in the initial Marketing Approval or by a subsequent
amendment) and * * * (provided that such achievement results in
additional Net Sales of more than US$* * * in the first year after the
First Commercial Sale thereof in the United States)
 Drug-Induced Angioedema
 Milestone Event
    
    Milestone Payment1.
    
    
    Receipt of Marketing Approval * * *, which Marketing Approval provides
for an expiration dating period based on a shelf life of at least * *
* (whether such period is included in the initial Marketing Approval
or by a subsequent amendment)
    
    US$* * *2a.
    
    
    * * *:
    
    US$* * ** * *, which Marketing Approval provides for an expiration dating
period based on a shelf life of at least * * * (whether such period is
included in the initial Marketing Approval or by a subsequent
amendment)2b.
    
    

If * * *, Product proposed by Jerini and provided that such Additional
Formulation Product will have * * * years of market exclusivity after
the date of First Commercial Sale in the United States:
    
    US$* * ** * *, which Marketing Approval provides for an expiration dating
period based on a shelf life of at least * * * (whether such period is
included in the initial Marketing Approval or by a subsequent
amendment) and achievement of * * * (provided that such achievement
results in additional Net Sales of more than US$* * * in the first
year after the First Commercial Sale thereof in the United States)
 22




---



##### 



Other Angioedema Indications
 Milestone Event
    
    Milestone Payment1a.
    
    If Kos, through its representation on the JDC, agreed to * * *:
    
    US$* * ** * *, which Marketing Approval provides for an expiration dating
period based on a shelf life of at least * * * (whether such
period is included in the initial Marketing Approval or by a
subsequent amendment)1b.
    
    * * * and provided that the Licensed Product for such indication will
have * * * of market exclusivity after the date of First Commercial
Sale in the United States:
    
    US$* * ** * *, which Marketing Approval provides for an expiration dating
period based on a shelf life of at least * * * (whether such period is
included in the initial Marketing Approval or by a subsequent
amendment) and * * * (provided that such achievement results in
additional Net Sales of more than * * * in the first year after the
First Commercial Sale thereof in the United States)
 7.3 Milestone Payments in R/A Field.
 Milestone Event
    
    Milestone Payment1.
    
    
    Receipt of Marketing Approval of * * *
    
    US$* * *2.
    
    
    Receipt of Marketing Approval of * * *
    
    US$* * *
 7.4 Sales Milestone Payment.
 7.5 Royalties.
 7.5.1 Royalty Rates.
 (i)
 23




---



##### 



(ii)
 (iii)
 (iv)
 (v)
 7.5.2 Royalty Term.
 7.5.3 Royalty Reductions.
 (a) Blocking Patents.
 (b) Generic Sales.
 7.6 Payments by Jerini in R/A Field.
 7.6.1 Milestone Payments.
 24




---



##### 



Milestone Event
    
    Milestone Payment1.
    
    
    Submission of an MAA for approval of * * *
    
    US$* * *2.
    
    
    Receipt of Marketing Approval of * * *
    
    US$* * *
 7.6.2 Royalties.
 (i)
 (ii)
 7.6.3 Royalty Term. Jerini Royalty Term
 7.7 Payments
 7.7.1 Payment Timing. Payor Payee
 7.7.2 Payment Method.
 7.7.3 Currency Conversion.
 25




---



##### 



7.8 Records; Audit
 7.8.1 Records Retention. Payment Records
 7.8.2 Audit. provided however
 7.8.3 Payment of Additional Amounts.
 7.8.4 Termination of Rights.
 7.8.5 Confidentiality
 7.9 Taxes
 7.9.1 Withholding Taxes Withholding Taxes
 26




---



##### 



7.9.2 Additional Withholding Taxes
 8. Licenses; Intellectual Property Rights
 8.1 Licenses
 8.1.1 Licensed Technology
 8.1.2 Trademarks
 27




---



##### 



8.1.3 License to Kos Inventions
 8.1.4 Reservation of Rights; Restrictive Covenants.
 8.2 Sublicenses
 8.2.1
 8.2.2
 8.2.3
 8.3 Jerini Right of First Negotiation
 8.3.1
 28




---



##### 



8.3.2
 8.3.3 Exercise Notice Exercise Period Final
Term Sheet provided
 8.4 Kos Right of First Negotiation
 8.4.1 Jerini Data
Room Notice
 8.4.2
 8.4.3
 8.4.4 New Indications Term Sheet provided * * *.
 29




---



##### 



9. Filing, Prosecution, Maintenance, and Defense of Licensed Patents
 9.1 Aventis Patents
 9.1.1 Responsibility
 9.1.2 Enforcement
 (a) Initiation.
 (b) Cooperation.
 (c) Recovery.
 9.2 Other Licensed Patents Jerini Licensed
Patents
 9.2.1 Responsibility
 30




---



##### 



9.2.2 Enforcement
 (a) Initiation.
 (b) Cooperation.
 (c)  Recovery.
 9.3 Defense of Infringement Claims provided
 31




---



##### 



9.4 Patent Term Restoration
 9.5 Consequences of Patent Challenge
 9.5.1 Termination on Patent Challenge Patent Challenge provided
 9.5.2 Sublicensees
 9.6 Orange Book Listing of Patents.
 10. Ownership of Inventions
 10.1 Disclosure.
 32




---



##### 



10.2 Ownership of Inventions
 10.2.1 Assigned Inventions
 10.2.2 Kos Inventions
 10.3 Rights From Sublicensees, Affiliates, and Contractors
 10.3.1 Of Kos
 10.3.2 Of Jerini
 10.4 Further Assurances
 11. Representation and Warranties; Covenants
 11.1 Jerini Warranties
 (a)
 (b)
 (c)
 (d)
 33




---



##### 



(e)
 (f)
 (g)
 (h)
 (i)
 (j)
 (k)
 (l)
 (m)
 34




---



##### 



(n) Exhibit A
 11.2 Kos Warranties.
 11.3 DISCLAIMER OF WARRANTY.
 12. Confidentiality
 12.1 Definition. Disclosing Party Receiving Party Confidential Information Confidentiality Agreement
 12.2 Exclusions.
 (a)
 (b)
 35




---



##### 



(c)
 (d)
 (e)
 12.3 Disclosure and Use Restriction.
 12.4 Authorized Disclosure.
 12.4.1 provided provided further
 12.4.2 provided
 12.4.3 provided
 12.4.4
 12.4.5
 36




---



##### 



12.4.6
 12.5 Use of Name.
 12.6 Press Releases
 12.6.1 Exhibit E Public Disclosure
 12.6.2
 12.6.3 SEC BAFIN provided
 12.6.4
 12.7 Terms of Agreement to be Maintained in Confidence.
 37




---



##### 



provided
 12.8 Additional Obligations Under Aventis Agreement Exhibit F
 12.9 Provision of Information to Sanofi-Aventis
  13. Term and Termination
 13.1 Term Effective Date Term
 13.2 Termination for Material Breach
 13.2.1 Breaching Party Material Breach Non-Breaching Party
 13.2.2
 38




---



##### 



13.2.3
 13.3 Termination at Will provided
 13.4 Termination of Licenses Under Aventis Agreement provided
   13.5 Termination for Failure to Execute Equity Investment Agreement Exhibit D Equity Agreement provided .
 13.6 Consequences of Expiration and Termination
 13.6.1 Expiration of Term.
 (a)
 39




---



##### 



(b) provided
 13.6.2 Early Termination.
 (a)
 (b)
 (c)
 (d)
 (e)
 40




---



##### 



13.6.3 Sale of Inventory
 13.6.4 Transfer Plan.
 13.6.5 Partial Termination for Jerini Breach
 13.6.6 Survival.
 14. Indemnification and Insurance
 14.1 Indemnification by Jerini. Losses Third Party Claims
 14.2 Indemnification by Kos.
 41




---



##### 



14.3 Indemnification Procedure
 14.3.1 Notice of Claim. Indemnified Party Indemnifying Party Indemnification Claim Notice provided, however, Indemnitees Indemnitee
 14.3.2 Control of Defense.
 14.3.3 Right to Participate in Defense. provided
 14.3.4 Settlement.
 42




---



##### 



14.3.5 Cooperation.
 14.4 Expenses.
 14.5 Insurance.
 15. Limitation of Liability
  43




---



##### 



16. Miscellaneous
 16.1 Assignment. provided ab initio
 16.2 Essential Basis.
 16.3 Severability.
 16.4 Governing Law; Dispute Resolution
 16.4.1 Dispute
  16.4.2
 44




---



##### 



16.4.3
 16.4.4
 16.4.5 Notices.
 If to Jerini, to:Jerini US, Inc.c/o Jerini AGInvalidenstraße 13010115 BerlinGermanyAttention: Chief Executive OfficerFacsimile: +49-30-978 93-105With a copy to:Cooley Godward LLP11951 Freedom DriveReston, Virginia 20190USAAttention: Matthias AlderFacsimile: +1-703-456-8100If to Kos, to:Kos Life Sciences, Inc.c/o Kos Pharmaceuticals, Inc.1 Cedar Brook DriveCranbury, New Jersey 08512-3618Attention: Chief Executive OfficerFacsimile: +1-609-495-0920Attention: Chief Financial OfficerFacsimile: +1-954-331-3877
 45




---



##### 



With a copy to:Kos Pharmaceuticals, Inc.1 Cedar Brook DriveCranbury, New Jersey 08512-3618Attention: Andrew I. KovenExecutive Vice President, General Counseland Corporate SecretaryFacsimile: +1-609-495-0907
  16.5 Entire Agreement; Modifications.
 16.6 Relationship of the Parties.
 16.7 Waiver.
 16.8 Counterparts.
 46




---



##### 



16.9 No Benefit to Third Parties.
 16.10 Further Assurance. 16.11 English Language.
 16.12 No Drafting Party
 16.13 Construction
 Remainder of page intentionally left blank.  Signature page follows.
 47




---



##### 



In Witness Whereof,
 Jerini
US, Inc.
   Kos Life Sciences, Inc.
    Signature page to Collaboration and License Agreement
 48