<DOCUMENT>
<TYPE>EX-2.1
<SEQUENCE>4
<FILENAME>ex2-1_021003isaly.txt
<DESCRIPTION>STATEMENT OF CONTROL PERSON
<TEXT>
                                                                    Exhibit 2.1
                                                                    -----------

                             Statement of Control Person


The Statement on Schedule 13G/A dated February 10, 2003 with respect to the
common stock, $.001 par value, of Enzon Inc. is filed by Samuel D. Isaly in
accordance with the provisions of Rule 13d-1(b) and Rule 13d-1(k) respectively
as a control person (HC) of OrbiMed Advisors LLC and OrbiMed Advisors Inc.

OrbiMed Advisors Inc. and OrbiMed Advisors LLC file this statement on Schedule
13G/A in accordance with the provisions of Rule 13d-1(b) and Rule 13d-1(k),
respectively, as investment advisors (IA).


</TEXT>
</DOCUMENT>