Exhibit 10(b)
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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
HIGHLY CONFIDENTIAL
April 21, 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 and
as described in our telephone conversation earlier today, we wish to make you
aware of a change in the previously negotiated terms with River’s Edge
Pharmaceuticals, LLC (“River’s Edge”) to the proposed Amended Nicomide License
Agreement and to reconfirm your April 3, 2009 waiver of Section 10.4(b) of the
Merger Agreement relating to the license transaction and your continued
agreement to the terms of the Release and Third Amendment to the Merger
Agreement to avoid any misunderstanding in the future.
     As you know, DUSA has been engaged in negotiations to broaden the Nicomide
patent license with River’s Edge and as of April 3, 2009, we believed that the
negotiations were concluded as execution copies of the documents were being
circulated. However, River’s Edge has requested a change relating to the period
in which DUSA may receive the full consideration for the license and transfer of
the product rights (i.e., it could take longer for DUSA to receive the
$5,000,000 consideration than the thirty (30) months originally verbally agreed
by River’s Edge and described to you).
     As a result, in the event that DUSA has not received $5,000,000 from
River’s Edge, on or before the Milestone Termination Date, as amended (i.e.,
December 31, 2011) by the Third Amendment to the Merger Agreement, and River’s
Edge is still marketing Nicomide under the Amendment to the License Agreement,
DUSA shall, nonetheless, credit the Net Sales, as defined in the Third Amendment
to the Merger Agreement, with an amount equal to the difference between
$5,000,000 and the amount actually paid to DUSA by River’s Edge as of the
Milestone Termination Date. DUSA will then determine, using the cumulative Net
Sales amount including any difference above, whether the One Million Dollars
($1,000,000) Milestone Payment is due to the Sirius Shareholders (for achieving
cumulative Net Sales of the Products of $35,000,000

 

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under Section 2.2(c)(ii)(B) of the Merger Agreement) or whether the Two Hundred
Fifty Thousand Dollar ($250,000) payment specified in the Release is due.
Please reconfirm your 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 and your agreement to the terms of the
Release and Third Amendment to the Merger Agreement, all of which are attached
to this letter, by signing this letter below and returning it to DUSA as soon as
possible.

            Very truly yours,
      /s/ Richard C. Christopher       Richard C. Christopher      Vice
President, Finance and
Chief Financial Officer     

We hereby 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 and agree to the terms of the Release and Third Amendment
to the Merger Agreement.

         
/s/ Frank Pollard
  /s/ Jeffrey Bernstein    
 
       
Frank Pollard
  Jeffrey Bernstein    

Date: 04/21/2009
 
Date: April 21, 2009