EXHIBIT 16.1



                         Arthur Andersen LLP Letterhead



Office of Chief Accountant
Securities and Exchange Commission
450 Fifth Street, N.W.
Washington, D.C.  20549

May 24, 2002


Dear Sir/Madam:


We have read the first and second  paragraphs of Item 4 included in the Form 8-K
dated  May 24,  2002 of the  Cytogen  Retirement  Savings  Plan  filed  with the
Securities and Exchange Commission on May 24, 2002 and are in agreement with the
statements  contained  therein to the extent  such  statements  relate to Arthur
Andersen LLP.

Very truly yours,

/s/ Arthur Andersen LLP

Arthur Andersen LLP






Cc:      Mr. Lawrence R. Hoffman
         Chief Financial Officer
         Cytogen Corporation