Exhibit
4.06


 


AMENDMENT TO RIGHTS AGREEMENT


 


THIS
AMENDMENT (the “Amendment”), dated as of the 4th
day of March, 2005, to the Rights Agreement (the “Rights Agreement”), dated May
6, 2003, between ALLOS THERAPEUTICS, INC., a Delaware corporation (the “Company”)
and MELLON
INVESTOR SERVICES LLC (the “Rights Agent”), is being executed at the
direction of the Company.  Capitalized
terms used in this Amendment and not otherwise defined herein shall have the
meanings given them in the Rights Agreement.


 


WHEREAS, Section 27 of the Rights
Agreement provides that the Company and the Rights Agent shall, if the Company
so directs, supplement or amend any provision of the Rights Agreement without
the approval of any holders of the Rights, any such supplement or amendment to
be evidenced by a writing signed by the Company and the Rights Agent; and


 


WHEREAS, pursuant to Section 27 of the
Rights Agreement, the Company has delivered to the Rights Agent a certificate
signed by an authorized officer of the Company certifying that the proposed
amendment of the Rights Agreement is in compliance with the terms of
Section 27 of the Rights Agreement.


 


NOW, THEREFORE, in consideration of the
foregoing and the agreements, provisions and covenants herein contained, the
parties agree as follows:


 


1.                                      Section 1(h)
shall be amended and restated in its entirety as follows:


 


“Excluded Stockholder” shall mean Warburg
Pincus Private Equity VIII, L.P. (including its Affiliates and Associates)
(“Warburg”); provided, however, that Warburg shall not be an Excluded
Stockholder if, without the prior approval of the Board of Directors, Warburg
becomes the Beneficial Owner of more than 44% of (x) the outstanding Common
Shares, plus (y) the Common Shares issuable upon the exchange of the Company’s
outstanding Series A Exchangeable Preferred Stock (including any quarterly
accruing dividends thereon) (the “Exchange Shares”), calculated as if such
Exchange Shares had been issued pursuant to an exchange as of immediately
following the original issuance of each such share of outstanding Series A
Exchangeable Preferred Stock.


 


2.                                      The
Rights Agreement shall not otherwise be supplemented or amended by virtue of
this Amendment, but shall remain in full force and effect.  This Amendment may be executed in one or more
counterparts, all of which shall be considered one and the same amendment and
each of which shall be deemed an original.


 


[Remainder of Page Intentionally Left Blank]


 


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


 


	
  ALLOS
  THERAPEUTICS, INC.

  	
  MELLON
  INVESTOR SERVICES LLC, as Rights

  Agent

  
	
   

  	
   

  
	
  By:

  	
  /s/ Marc H. Graboyes

  	
   

  	
  By:

  	
  /s/ Tiffany J. Skiles

  	
   

  
	
   

  	
   

  
	
  Name:

  	
  Marc H. Graboyes

  	
   

  	
  Name:

  	
  Tiffany J. Skiles

  	
   

  
	
   

  	
   

  
	
  Title:

  	
  Vice President, General Counsel

  	
   

  	
  Title:

  	
  Client Relationship Executive

  	
   

  
										



 


 


SIGNATURE PAGE TO AMENDMENT TO RIGHTS AGREEMENT