EX-10.A






Exhibit 10(a)








	 	 	 
	By E-mail
	 	 
	Mr. Frank Pollard

	 	Mr. Jeffrey Bernstein
	3615 RFD

	 	9739 Monte Mar Drive
	Long Grove, Illinois 60047

	 	Los Angeles, CA 90035






Re: Amended Nicomide License and Third Amendment to Merger Agreement

HIGHLY CONFIDENTIAL




April 3, 2009




Gentlemen:




     We are writing to you in your capacity as the Sirius Shareholder Representatives under the
terms of the merger agreement between DUSA Pharmaceuticals, Inc. (“DUSA”) and Sirius Laboratories,
Inc. (“Sirius”) dated December 30, 2005, as amended (the “Merger Agreement”). As explained below,
we require a further limited waiver of Section 10.4(b) of the Merger Agreement.



     DUSA has been engaged in negotiations to broaden the Nicomide® patent license with
River’s Edge Pharmaceuticals, LLC (“River’s Edge”) to which you agreed in August, 2008. Our
discussions with River’s Edge are about to conclude. DUSA has agreed to amend the non-exclusive
license to the patent which claims Nicomide® for the prescription pharmaceutical market,
to an exclusive license on the terms we have discussed with you verbally and in writing.



     In addition, you may also be aware that, Dr. Joel Bernstein, acting on behalf of a group
Sirius Principal Shareholders (as defined in the Merger Agreement) has threatened DUSA with
litigation alleging various breaches of the Merger Agreement by DUSA. DUSA wishes to resolve all
issues with the former Sirius shareholders. In that regard, in addition to the consent to waive
Section 10.4 of the Merger Agreement in connection with the amended Nicomide license, DUSA is
proposing that the Sirius Representatives and the Sirius Principal Shareholders enter into a
Release and the Third Amendment to the Merger Agreement in the form of Exhibits A and B attached to
and made a part of this letter agreement.



     In consideration of the waiver of Section 10.4 and the Release and Third Amendment to the
Merger Agreement, DUSA agrees to pay One Hundred Thousand Dollars ($100,000) to the Sirius
Shareholders on a pro rata basis based on their respective interests in Sirius upon the execution
of this letter and the Exhibits by all respective parties, and a potential second payment of Two
Hundred Fifty Thousand Dollars ($250,000) as set forth in the Release.



     If you consent to the waiver, we ask that one or both of you sign this letter in the space
below and FAX it back to me at 978-909-1016.



CORPORATE HEADQUARTERS 25 Upton Drive, Wilmington, MA 01887 — Phone 978.657.7500, Fax 978.657.9193

TORONTO OFFICE 555 Richmond Street West, Suite 300, P.O. Box 704, Toronto, Ontario M5V 3B1 Phone 416.363-5059, Fax 416.363.6602

WWW.dusapharma.com






 









 








	 	 	 	 	 
	 	Very truly yours,

 	 
	 	/s/ Robert F. Doman  	 / 4-23-09 
	 	Robert F. Doman  	 
	 	President and Chief Executive Officer 	 
	 


We hereby (i) consent pursuant to Section 15.10 of the Merger Agreement to waive Section 10.4(b) of
the Merger Agreement to allow DUSA to enter the Amendment to the License Agreement under the
principal terms presented to us.




	 	 	 	 	 
	/s/ Frank Pollard

	 	/s/ Jeffrey Bernstein
	 	 
	 

	 	 	 	 
	Frank Pollard

	 	Jeffrey Bernstein	 	 
	 
	Date: 04/03/2009

	 	Date: April 3, 2009	 	 







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