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) January 7, 2002


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





       Delaware                         0-12957                 22-237286
(State or other jurisdiction         (Commission              (IRS Employer
  of 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



                                      N/A
          (Former name or former address, if changed since last report)


                                       1



Item 5.  Other Events

     On  January  7,  2002 the  Registrant,  together  with  Inhale  Therapeutic
Systems, Inc. ("Inhale"),  announced the formation of a broad strategic alliance
that  will  serve to  enhance  each  company's  business  model.  As more  fully
described below, the most significant terms of the alliance are:

     o     The Registrant and Inhale will  collaborate to develop three products
     to be  specified  over  time  based  on the  Inhale  Inhance(TM)  pulmonary
     delivery  platform  and  SEDS(TM)   supercritical   fluids  platform.   The
     collaboration  will have a particular  focus on the development of products
     in the oncology  field as the  Registrant has a first option to designate a
     product in this field until the three  products have been  specified or the
     agreement otherwise terminates.  The Registrant will be responsible for the
     commercialization and clinical development while Inhale will be responsible
     for the product development and manufacturing of the products.

     o     Inhale will be solely  responsible for licensing the Registrant's PEG
     patents, which includes over 40 U.S. patents, to third parties. Inhale will
     also have the option to license  the  Registrant's  PEG  patents for use in
     Inhale's proprietary  products.  The Registrant will receive a royalty or a
     share of profits on final product sales of any products that are subject to
     a license under the  Registrant's  PEG patents,  including its branched PEG
     patents. The Registrant retains the right to use its PEG technology for its
     own proprietary products and those it may develop with co-commercialization
     partners.

     o     The Registrant  will have the option to license  Inhale's  PEGylation
     patents for the Registrant's  proprietary  products and Inhale will receive
     royalties on sales of any such products.

     o     The  Registrant   and  Inhale  will  explore  the   development  of
     non-invasive  delivery of single-chain  antibody  (SCA(R)) products via the
     pulmonary  route.  Inhale will become the  exclusive  pulmonary  technology
     provider  for  the  Registrant's  single-chain  antibody  technology  using
     Inhale's  proprietary  Inhance  pulmonary  drug delivery  technology for at
     least three years assuming success in the initial proof of concept program.

     o      The  Registrant   purchased  $40  million  of  newly  issued  Inhale
     convertible preferred stock.

     o     The  Registrant  and Inhale have agreed to  settlement of the patent
     infringement   litigation  filed  by  the  Registrant   against   Inhales's
     Shearwater subsidiary.

     Product Development Agreements

     The Registrant  and Inhale will jointly  develop up to three products using
Inhale's platform technologies:  the Inhance(TM) pulmonary delivery platform and
SEDS(TM)  supercritical  fluids platform.  The two companies will collaborate to
identify  product  candidates.   Inhale  will  be  responsible  for  formulation
development,   delivery  system  supply,  and  in  some  cases,  early  clinical
development.   The  Registrant  will  have   responsibility  for  most  clinical
development and for commercialization.

     The two companies have agreed to  collaborate on realizing the  significant
therapeutic and competitive  potential offered by single-chain antibody (SCA(R))
products when  administered  by the  pulmonary  route.  The two  companies  will
initially  focus on exploring the utility of the Inhale  pulmonary

                                        1



platform  for  single-chain  antibodies  and then move to  develop  single-chain
products  that  will  complement  the  current  use of  antibodies  through  the
injectable route.  Single-chain  antibodies are genetically  engineered proteins
designed to expand on the therapeutic and diagnostic  applications possible with
monoclonal  antibodies.  The  Registrant  retains all rights to its SCA products
while Inhale  retains all rights to its own  technology.  Inhale will become the
exclusive  pulmonary  technology  provider  for  the  Registrant's  single-chain
antibody  technology using Inhale's Inhance  pulmonary drug delivery  technology
for at least the next three years assuming a successful initial proof-of-concept
program.

     Technology Licensing

     The  Registrant   will  grant  to  Inhale  the  exclusive  right  to  grant
sub-licenses under the Registrant's PEG patents to third parties. The Registrant
will receive a share of profits for certain products that currently  incorporate
the Registrant's branched PEG technology and royalties on sales of products that
are subject to new  sublicenses  that Inhale  grants to its  partners  under the
Registrant's PEG patents.  For Pegasys,  Inhale  anticipates that the Registrant
will  receive  0.5% or less of Roche's  sales,  which  represents  equal  profit
sharing with Inhale on this product. Inhale has confirmed that there are certain
other  products in Inhale's  current  product  pipeline  that use  branched  PEG
technology.  Inhale  has  advised  the  Registrant  that,  with  respect to such
products, it expects to receive a higher percentage of partner sales in the form
of royalty  and  manufacturing  revenues  than it is  entitled  to receive  with
respect to Pegasys.  For these  products,  Inhale will provide a profit-share to
the Registrant,  but the percentage is expected to be considerably less than for
Pegasys, since Inhale anticipates receiving a higher percentage of its partner's
sales. The Registrant retains the right to use all of its PEG technology for its
own  product   portfolio,   as  well  as  for  those  products  it  develops  in
co-commercialization  collaborations with third parties. It is the intent of the
parties  that Inhale will be  responsible  for  marketing  PEG  services and the
Registrant and Inhale PEG technology to third parties.

     The  Registrant  will  have  an  option  to  license  Inhale's   PEGylation
technology  for use  with  its  own  portfolio  products.  Inhale  will  receive
royalties  on  any  sales  of  Registrant   PEGylation   products  using  Inhale
technology.  The Registrant will have the ability to request  PEGylation  supply
and services from Inhale.

     Certain drug molecules will be excluded from both the product collaboration
and PEG licensing agreements.

     Stock Purchase Agreement

     The  Registrant  purchased  $40  million of Inhale  non-voting  convertible
preferred stock. The conversion price of the preferred stock is $22.79 per share
of common  stock,  which is based on a 25% premium to the average  Inhale common
stock  closing bid price over the last 20 trading  days.  In the event  Inhale's
common stock price three years from the date of issuance of the preferred stock,
or earlier in certain  circumstances,  is less than $22.79, the conversion price
will be adjusted  downward,  although  in no event will it be less than  $18.23.
Conversion  of the  preferred  stock into common can occur  anywhere from 1 to 4
years  following  the  issuance  of the  preferred  stock or  earlier in certain
circumstances.  The Registrant has been granted certain  registration rights for
the common stock issuable upon conversion.

     Settlement Agreement

     In addition to establishing this alliance, the two companies have agreed to
settle the patent  infringement  suit related to the  Registrant's  branched PEG
technology  filed  in  1998  by  the  Registrant  against  Inhale's   subsidiary
Shearwater.  Inhale will receive licensing access to the contested patents under
the  cross-license  agreement  described above. The Registrant will receive a $3
million  payment  from  Inhale to cover  expenses  incurred in  connection  with
defending  the branched PEG patents that both  companies  will now  commercially
exploit.

                                       2



     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 Registrant's Form 10-K, Form 10-Q's and Form
8-K's  on file  with the SEC,  including  without  limitation,  the  outcome  of
clinical trials,  regulatory  review,  manufacturing  capabilities and marketing
effectiveness.

                                       3



                                   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:   January 8, 2002

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


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


                                       1