SECURITIES AND EXCHANGE COMMISSION

                             Washington, D.C. 20549

                                    FORM 8-K

                                 CURRENT REPORT

     Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

         Date of Report (Date of earliest event reported) July 24, 2001


                                   ENZON, INC.
             (Exact name of registrant as specified in its charter)

           Delaware                      0-12957                   22-2372868
(State or other jurisdiction of        (Commission                (IRS Employer
        incorporation)                 File Number)              Identification)


                20 Kingsbridge Road, Piscataway, New Jersey 08854
               (Address of principal executive offices) (Zip Code)


       Registrant's telephone number, including area code: (732) 980-4500


                                           NA
              (Former name or former address, if changed since last report




Item 5.  Other Events


     On July 24, 2001, the Company announced the initiation of patient dosing in
a Phase II clinical trial for PROTHECAN(R)  (PEG-camptothecin)  in patients with
small-cell lung cancer.  This Phase II trial is an open-label  study,  that will
enroll up to 60 patients and evaluate the anti-tumor activity of PROTHECAN.


     The Company  expects to initiate  additional  Phase II trials in  non-small
cell  lung and  other  cancers  with  PROTHECAN  as both a  single-agent  and in
combination with other oncolytic agents.

     The pharmacokinetic  data from ongoing Phase I clinical trials of PROTHECAN
show that biologically  relevant plasma  concentrations of free camptothecin are
sustained  for up to 168 hours after a single dose of PROTHECAN  and  anti-tumor
activity  has been  observed.

     PROTHECAN  is  a   PEG-enhanced   version  of  a  small   molecule   called
camptothecin,  which is an  anti-cancer  compound  in the class of drugs  called
topoisomerase I inhibitors.  Camptothecin,  which was originally  studied at the
National  Institutes of Health, is a potent  topoisomerase  inhibitor.  For many
years  camptothecin  has been known to be a very effective  oncolytic agent, but
drug  delivery  problems  have  limited its use. Two  camptothecin  derivatives,
topotecan  and  irinotecan,  have been  approved by the FDA for the treatment of
small-cell lung and colorectal cancers,  respectively.  While these two products
are more soluble than camptothecin,  their efficacy rate is relatively  limited.
Despite their  limitations,  these two products together achieved 2000 worldwide
sales of approximately $580 million.

     On July 26, 2001, the Company  announced that  Schering-Plough  Corporation
has reported that it has been granted marketing  approval from the U.S. Food and
Drug Administration (FDA) for REBETOL (ribavirin,  USP) Capsules as a separately
marketed  product  for use only in  combination  with  INTRON(R)  A  (interferon
alfa-2b,  recombinant)  Injection  for the  treatment of chronic  hepatitis C in
patients  with  compensated  liver  disease  previously   untreated  with  alpha
interferon or who have relapsed following alpha interferon  therapy.  The safety
and efficacy of REBETOL Capsules with  interferons  other than INTRON A have not
been established.



     REBETOL  had  been  previously  approved  in the  United  States  for  this
indication  only as a  component  of  REBETRON(TM)  Combination  Therapy,  which
contains   REBETOL  Capsules  and  INTRON  A  Injection  in  a  single  package.
Schering-Plough  has reported it will  continue to market  REBETRON  Combination
Therapy in the United States.

     Schering-Plough  expects REBETOL Capsules,  available by prescription only,
to be available nationwide sometime this fall.

     In  February  2001,  Schering-Plough  submitted  a  supplemental  Biologics
License  Application  (sBLA) to the FDA seeking marketing approval of PEG-INTRON
for use in  combination  therapy  with  REBETOL  for the  treatment  of  chronic
hepatitis C in patients not previously  treated with  interferon  alpha who have
compensated liver disease and are at least 18 years of age.

     PEG-INTRON  (peginterferon  alfa-2b) is a longer-acting form of INTRON(R) A
(interferon alfa-2b, recombinant) Injection that uses proprietary PEG technology
developed   by   Enzon.   Under   the   Company's   licensing   agreement   with
Schering-Plough,   Enzon  is  entitled  to  royalties  on  worldwide   sales  of
PEG-INTRON.

     Except for the historical information herein, the matters discussed in this
Form 8-K include  forward-looking  statements that may involve a number of risks
and uncertainties.  Actual results may vary significantly based upon a number of
factors which are described in the Company's Form 10-K, Form 10-K/A, Form 10-Q's
and Form  8-Ks on file  with the SEC,  including  without  limitation,  risks in
obtaining  and  maintaining  regulatory  approval for  indications  and expanded
indications, market acceptance of and continuing demand for Enzon's products and
the impact of competitive products and pricing.






                                   SIGNATURES

     Pursuant to the  requirements  of the Securities  Exchange Act of 1934, the
Registrant  has duly  caused  this  report  to be  signed  on its  behalf by the
undersigned hereunto duly authorized.

Dated: July 26, 2001

                                                    ENZON, INC.
                                       --------------------------------------
                                                   (Registrant)



                                    By: /s/ Kenneth J. Zuerblis
                                       --------------------------
                                        Kenneth J. Zuerblis
                                        Vice President, Finance, Chief Financial
                                        Officer and Secretary