Re: Amended Nicomide License and Third Amendment to Merger Agreement
April 3, 2009
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