UNITED STATES
                SECURITIES AND EXCHANGE COMMISSION

                      Washington, DC  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): May 11, 1998



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


  DELAWARE                      0-19855                 04-2662345       
(State or other               (Commission              (IRS Employer
jurisdiction of               File Number)             Identification No.)
incorporation)


        97 South Street, Hopkinton, Massachusetts  01748   
       (Address of principal executive offices) (Zip Code)


Registrant's telephone number, including area code:  (508) 435-2331





<PAGE>
Item 5.  Other Events.

Settlement Agreement

          Effective as of May 1, 1998, the Registrant entered into a
Settlement Agreement (the "Seragen Canada Settlement Agreement") with its
Canadian affiliate, Seragen Biopharmaceuticals Ltd./Seragen Biopharmaceutique
Ltee ("Seragen Canada"), and Sofinov Societe Financiere d'Innovation Inc.,
Societe Inovatech du Grand Montreal, MDS Health Ventures Inc., Canadian
Medical Discoveries Fund Inc., Royal Bank Capital Corporation, and Health Care
and Biotechnology Venture Fund (collectively, the "Investor Shareholders"). 
The Seragen Canada Settlement Agreement provides for the purchase by Seragen
Canada of all shares of Seragen Canada capital stock currently held by the
Investor Shareholders for an aggregate amount equal to Seragen Canada's cash
and liquid investments on hand after the payment of specified expenses.  As of
February 28, 1998, Seragen Canada held approximately $9,400,000 in cash and
liquid investments.  Such purchase transaction is expected to occur on or
prior to June 15, 1998.  Upon the consummation of Seragen Canada's purchase of
the Investor Shareholders' Seragen Canada shares, mutual releases among the
Registrant, Seragen Canada, and the Investor Shareholders will become
effective and a November 22, 1995 Shareholders Agreement and other specified
agreements executed in connection with the original organization of Seragen
Canada in November 1995 will be terminated.  The Seragen Canada Settlement
Agreement also provides for issuance by the Registrant of an aggregate of
$2,400,000 worth of its common stock upon the later to occur of (a) the
closing date for Seragen Canada's purchase of the Investor Shareholders'
Seragen Canada shares and (b) the earliest to occur of (i) an offering by the
Registrant of additional shares of its capital stock with net proceeds to the
Registrant of $10,000,000, (ii) the consummation of a disposition of the
Registrant, whether by way of a merger or otherwise, or substantially all of
the Registrant's assets, and (iii) January 31, 1999, subject to certain
qualifications.  The Investor Shareholders are accorded certain registration
rights with respect to the shares of the Registrant's common stock to be
issued to them.  


Agreement to be Acquired

          On May 11, 1998, the Registrant entered into an Agreement and Plan
of Reorganization (the "Merger Agreement") with Ligand Pharmaceuticals
Incorporated ("Ligand") and its wholly-owned special purpose subsidiary Knight
Acquisition Corporation ("Merger Sub").  The Merger Agreement provides for the
merger, subject to approval by the Registrant's shareholders entitled to vote
thereon, of Merger Sub into the Registrant with the result that the Registrant
will become a wholly-owned subsidiary of Ligand.  In connection with the
execution and delivery of the Merger Agreement, shareholders of the Registrant
holding between 55 and 59 percent of the voting power of the Registrant's
outstanding voting capital stock, including all officers and directors of the
Registrant, entered into agreements with Ligand, which agreements are
supported by irrevocable proxies, to vote their shares in favor of the
transactions contemplated by the Merger Agreement and against competing
proposals. 

                                      1
<PAGE>

          In connection with the execution and delivery of the Merger
Agreement, the Registrant and its subsidiary Seragen Technology, Inc. ("STI")
entered into an Accord and Satisfaction Agreement, dated as of May 11, 1998
(the "Accord Agreement"), with certain creditors and preferred shareholders of
the Registrant.  Pursuant to the Accord Agreement, the parties thereto other
than the Registrant and STI agreed to accept merger consideration allocated to
them pursuant to the Merger Agreement as full and complete satisfaction of
certain of their rights and claims against the Registrant and STI. 

          Simultaneously with the execution and delivery of the Merger
Agreement, Ligand entered into an Option and Asset Purchase Agreement, dated
May 11, 1998 (the "Marathon Purchase Agreement"), with Marathon
Biopharmaceuticals LLC ("Marathon"), 520 Commonwealth Avenue Real Estate
Corporation ("520 Commonwealth"), and 660 Corporation ("660 Corp.") providing
for the purchase by Ligand of substantially all of the assets of Marathon on
or before January 31, 1999, but in any event not earlier than the closing of
the transactions contemplated by the Merger Agreement.  Marathon provides
manufacturing, clinical trial, and product research and development services
to the Registrant pursuant to a Service Agreement, dated as of February 14,
1997, as amended (the "Service Agreement"), between the Registrant and
Trustees of Boston University.

          In connection with the execution and delivery of the Merger
Agreement and the Marathon Purchase Agreement, the Registrant, Ligand,
Marathon, 520 Commonwealth, and 660 Corp. entered into an Extension Option
Agreement, dated May 11, 1998 (the "Extension Option Agreement"), providing
each of the Registrant and Ligand with the right to extend the termination
dates of the Merger Agreement and the Marathon Purchase Agreement in certain
circumstances. 
          
          The Registrant and Ligand issued a joint press release on May 11,
1998, announcing the signing of the Merger Agreement and related agreements. 
A copy of the press release is included as an exhibit hereto.


          Merger Agreement  

          The Merger Agreement provides for Merger Sub to be merged into the
Registrant, with the Registrant as the surviving corporation in the merger
(the "Surviving Corporation").  In connection with the consummation of the
merger (the "Merger Closing"), Ligand will deliver cash and shares of its
common stock to the shareholders and certain creditors of the Registrant,
thereby extinguishing the interest of the Registrant's existing shareholders
in the Registrant.  At the same time, the shares of the Merger Sub will be
converted into shares of the Surviving Corporation, with the result that the
Surviving Corporation will be a wholly-owned subsidiary of Ligand following
the Merger Closing.  Existing shareholders of the Registrant who dissent from
the merger transaction may, under Delaware law, pursue appraisal rights if
they so choose.  

                                      2
<PAGE>
          The Merger Agreement provides for a total payment by Ligand to the
Registrant's shareholders and creditors of $67,000,000, with a portion of this
amount payable only upon certain conditions, as described below.  Of this,
Ligand will pay $30,000,000 at the Merger Closing, payable in the form of cash
in the amount of $4,000,000 and shares of Ligand common stock in the amount of
$26,000,000 (the "Closing Consideration").  The cash portion of the Closing
Consideration will be used primarily to satisfy accounts payable and certain
other obligations of the Registrant.  Ligand may, at its option, increase the
amount of cash payable at the Merger Closing to satisfy certain of the
Registrant's payables, in which case the amount of stock consideration
included in the Closing Consideration will be correspondingly reduced.  The
shares of Ligand common stock to be delivered by Ligand at the Merger Closing
will be valued at $13.9875 per share, which is based on the trailing average
market price for the five trading days prior to May 11, 1998, the date on
which the Merger Agreement was executed.

          The remaining $37,000,000 of the merger consideration (the
"Milestone Consideration"; the Closing Consideration and Milestone
Consideration together, the "Merger Consideration") will be paid by Ligand six
months following the receipt by the Surviving Corporation of FDA approval for
the marketing, distribution and selling of DAB389IL-2 in the United States for
CTCL if such approval is supported to any material extent by clinical and
development efforts of the Registrant prior to the consummation of the merger. 
The Milestone Consideration will, however, only be payable by Ligand if the
required FDA approval is obtained within two years of the Merger Closing;
otherwise, Ligand is relieved of any obligation to pay the Milestone
Consideration.  Ligand may pay the Milestone Consideration in the form of cash
or Ligand common stock or a combination thereof.  Any stock delivered as part
of the Milestone Consideration will be valued on a trailing average market
price for the ten trading days prior to issuance.

          Ligand has agreed to take certain steps following the consummation
of the merger to facilitate the required approval of DAB389IL-2.  Those steps
include, among other things, the conduct of certain additional tests and
studies necessary to obtain such approval, and the avoidance of any changes in
the operations, personnel and facilities of Marathon if such changes could be
expected to adversely affect the prospects for FDA approval.  More generally,
Ligand has agreed to use commercially reasonable efforts to take all actions
after the Merger Closing that are necessary or appropriate to obtain the
required FDA approval of DAB389IL-2 by the second anniversary of the Merger
Closing.

          The Merger Consideration is to be distributed first to the holders
of Registrant's common stock and Series D preferred stock, next to certain
creditors of the Registrant, and finally to the preferred shareholders and
certain other creditors of the Registrant, all as set forth in Section 1.7 of
the Merger Agreement.  The holders of the Registrant's common stock and Series
D preferred stock are entitled to receive for each share of Registrant common
stock (for purposes of this distribution, shares of Series D preferred stock
will be deemed to have been converted into the number of shares of common
stock of the Registrant that such shares of Series D preferred stock would
have been converted into had the conversion been effected immediately prior to
the effective date of the merger) (a) in connection with the Merger Closing,

                                      3
<PAGE>
0.035746 shares of common stock of Ligand and, (b) if and only if the
Milestone Consideration is paid, cash or Ligand stock, as applicable, valued
at $0.23.  

          Certain creditors and obligees of the Registrant, including United
States Surgical Corporation and, to the extent of amounts payable by the
Registrant pursuant to the Service Agreement, Boston University and Marathon,
are entitled to receive a fixed amount of Merger Consideration in satisfaction
of the Registrant's obligations to such creditors and obligees.  The holders
of the Registrant's Series B preferred shares, the Registrant's executive
officers, and the Registrant's financial advisers will receive the amount of
Merger Consideration remaining after the distribution to the holders of the
Registrant's common stock and Series D preferred stock and the satisfaction of
the Registrant's financial obligations as of the Merger Closing.  These
distribution arrangements are reflected in Section 1.7 of the Merger
Agreement. 

          Ligand common stock to be delivered as part of the Merger
Consideration is required to be registered under federal securities laws so as
to permit immediate resale of the shares, subject to prospectus delivery
requirements under applicable SEC rules and certain trading volume limitations
that may be applicable under the SEC's Rule 145.  Boston University will be
prohibited from transferring Ligand common shares that it receives in the
merger until the later of the second anniversary of the Merger Closing and the
first anniversary of the issuance of such shares.  The restrictions described
in the foregoing sentence will not, however, apply to the Ligand common
shares, if any, that Boston University receives in respect of approximately
$5,900,000 owed to it and Marathon by the Registrant under the Service
Agreement between the Registrant and Marathon.  Executive officers of the
Registrant and the Registrant's financial advisers, Lehman Brothers Inc. and
Shoreline Pacific Institutional Finance ("Shoreline Pacific"), will be
prohibited from transferring 50 percent and 100 percent, respectively, of the
Ligand common shares that they receive in the merger until the ninetieth day
following issuance.  The right of Eli Lilly and Company ("Lilly") to transfer
Ligand common shares that it receives as Merger Consideration will be
restricted to the same extent as Ligand common shares previously issued to
Lilly by Ligand.
 
          The Registrant provides certain representations and warranties
regarding its business, financial condition, and assets.  In general,
representations and warranties given by the Registrant are given both as of
the date of the Merger Agreement and as of the date of the Merger Closing.  

          Ligand provides certain representations and warranties regarding its
business, financial condition, and assets.  In general, representations and
warranties given by Ligand relating to its business and financial condition
are given only as of the date of the Merger Agreement; representations and
warranties given by Ligand relating to its ability to consummate the Merger
Closing, such as the legal existence and authority of Ligand and Merger Sub,
are given both as of the date of the Merger Agreement and the date of the
Merger Closing.  

                                      4
<PAGE>
          A number of covenants apply to the Registrant's conduct of its
business between the date of the Merger Agreement and the Merger Closing. 
These covenants require the Registrant, among other things, to carry on its
business only in the usual and ordinary course and impose restrictions on,
among other things, the Registrant's ability to dispose of assets, enter into
licenses of its intellectual property, satisfy payables other than in the
ordinary course, or increase employee compensation.

          A $200,000 cash portion of the Closing Consideration will be placed
in escrow with State Street Bank and Trust Company.  In addition, revenues
received by the Surviving Corporation after the Merger Closing that are
attributable to the operation of the Registrant prior to the Merger Closing
will be deposited in the escrow account.  The escrow account will be used to
pay certain obligations of the Surviving Corporation that are attributable to
the operation of the Registrant prior to the Merger Closing.  Any amounts
remaining in the escrow account on the 120th day after the Merger Closing will
be distributed as additional Closing Consideration to those persons receiving
variable amounts of Closing Consideration under the Merger Agreement.  

          The obligations of the Registrant, on the one hand, and Ligand and
Merger Sub, on the other hand, to proceed with the consummation of the Merger
are conditioned, among other things, upon the approval of the merger by the
Registrant's stockholders, the receipt of required government approvals
(including clearance under the Hart-Scott-Rodino Antitrust Improvements Act)
and the effectiveness of Ligand's registration statement relating to the
Ligand common shares to be issued as Merger Consideration.  In addition, the
approval of the transaction by the Public Charities Division of the
Massachusetts Attorney General's office must be in full force and effect.  The
Registrant's obligations to consummate the merger are further conditioned on,
among other things, the accuracy of Ligand's representations and warranties as
of the date given and the satisfaction by Ligand of certain obligations to be
satisfied by it by the Merger Closing.  Ligand's obligation to consummate the
merger is further conditioned on, among other things, the accuracy of the
Registrant's representations and warranties as of the date given, the
satisfaction by the Registrant of obligations to be satisfied by it by the
Merger Closing, the absence of any general adverse development in the
Registrant's business (other than an adverse development relating to the FDA's
review of DAB389IL-2) resulting in a diminution of the value of the Registrant
by $5,000,000 or more, the accuracy of Marathon's representations and
warranties contained in the Marathon Purchase Agreement, the satisfaction by
Marathon of all obligations to be satisfied by it pursuant to the Marathon
Purchase Agreement by the Merger Closing, and no more than ten percent of the
Registrant's outstanding capital stock being the subject of dissenters' or
appraisal rights under Delaware law. 

          The Registrant has agreed that it will not take any action to
solicit or encourage a competing proposal; however, the board of the
Registrant may engage in negotiations with, or disclose any nonpublic
information relating to the Registrant or afford access to the properties,
books or records of the Registrant to, any person or entity that informs the
Registrant that it is considering making, or has made, a competing proposal.

                                      5
<PAGE>
          The Merger Agreement may be terminated by either the Registrant or
Ligand if the Merger Closing has not occurred by January 31, 1999.  However,
each of the Registrant and Ligand is provided with an option to extend this
expiration date subject to certain conditions, as described below in the
summary of the Extension Option Agreement.  In addition, the Merger Agreement
may be terminated by either the Registrant or Ligand if, among other things, a
final court order is entered prohibiting the merger, the Registrant's
stockholders at a meeting of the Registrant's stockholders fail to approve the
merger or approve a competing proposal, the other party breaches its
obligations under the Merger Agreement and such breach is not promptly cured,
or the other party becomes insolvent or seeks protection under the bankruptcy
laws.  Ligand also may terminate the Merger Agreement in the event any court
order or applicable law would prohibit Ligand from owning its assets and the
assets of the Registrant following the Merger Closing, in the event of an
occurrence of any general adverse development in the Registrant's business
(other than an adverse development relating to the FDA's review of DAB389IL-2)
resulting in a diminution of the value of the Registrant by $5,000,000 or
more, if any person purchases a majority of the Registrant's common stock, or
if the Registrant's board of directors withdraws its recommendation in favor
of the merger.  The Registrant may terminate the Merger Agreement if it
receives a competing proposal that the Registrant's board determines, after
consultation with counsel, to recommend to the Registrant's stockholders in
order to comply with the fiduciary duty of the board.

          Ligand is provided with the right to set off against Merger
Consideration payable to those persons receiving variable amounts of Merger
Consideration any damages that it may incur as a result of a breach of the
Registrant's representations, warranties or covenants under the Merger
Agreement.  However, Ligand may pursue such a set off only to the extent its
damages exceed an aggregate of $250,000, and in no event may the amount of set
off exceed an aggregate of $2,900,000.  Above the set off amount, Ligand is
permitted to pursue claims against persons receiving variable amounts of
Merger Consideration for damages as aforesaid, but only up to an amount of
$8,700,000.  Ligand is prohibited from pursuing claims under the Merger
Agreement against the Registrant common shareholders and from recovering
Merger Consideration paid to the Registrant common shareholders.  Ligand is
prohibited from pursuing claims under the Registrant's representations,
warranties and covenants of which it has not given notice prior to their
termination.  Except for certain representations and warranties relating to
matters of the Registrant's ability to validly consummate the merger and tax
matters, which survive, respectively, indefinitely and until the expiration of
the applicable statute of limitations, the Registrant's representations,
warranties and covenants under the Merger Agreement expire on the third
anniversary of the Merger Closing.

          In the event that Ligand terminates the Merger Agreement because of
a bankruptcy or the Registrant terminates the agreement because it has
received a competing proposal that the Registrant's board determines, after
consultation with counsel, to recommend to the Registrant's stockholders in
order to comply with its fiduciary duty, the Registrant is obligated to pay
Ligand a fee equal to $5,000,000 plus five percent of any additional value,
over the $67,000,000 contemplated by the Merger Agreement, realized by the
Registrant or its stockholders in connection with the consummation of a
competing acquisition proposal.  Such fee is, in addition, to be increased by
any Marathon losses assumed by Ligand in connection with its exercise of its
option under the Extension Option Agreement (described below) to extend the
term of the Merger Agreement beyond January 31, 1999.

          Ligand is required to maintain the Registrant's existing directors
and officers insurance policy in effect for the remainder of its term and, for
one year after the expiration of such policy, to use reasonable efforts either
to extend such policy or to cause current directors and officers of the
Registrant to be covered by directors and officers insurance comparable to
that maintained for Ligand's directors.  In addition, Ligand is required to

                                      6
<PAGE>
cause the Surviving Corporation to maintain the Registrant's existing
indemnification obligations in effect for the benefit of current and past
directors and officers of the Registrant.


          Accord Agreement

          The Accord Agreement provides that the signatories other than the
Registrant and STI will accept the amount of Merger Consideration allocated to
them in the Merger Agreement as full and complete satisfaction for their
specified claims against the Registrant, as follows:

          (1)     Boston University, Leon Hirsch, Turi Josefsen, and Gerald
and Loretta Cassidy agree to accept the right to receive the Merger
Consideration as satisfaction of all claims that they may have with respect to
the Registrant's outstanding Series B preferred stock and, at the Merger
Closing, to surrender their shares of Series B preferred stock for termination
and cancellation.

          (2)     Boston University agrees to accept the right to receive the
Merger Consideration as satisfaction of all claims that it may have to a cash
payment in the amount of $4,600,000 arising from the automatic conversion of
the Registrant's outstanding Series C preferred stock that occurred on March
30, 1998 and agrees to surrender immediately prior to the effective time of
the merger, without additional compensation, to the Registrant for
cancellation the 3,360,625 shares of the Registrant's common stock that it
received in connection with the March 30, 1998 conversion of the Registrant's
outstanding Series C preferred stock.

          (3)     Boston University, Leon Hirsch, Turi Josefsen, Gerald and
Loretta Cassidy, and United States Surgical Corporation agree to accept the
right to receive the Merger Consideration as satisfaction of all claims that
they may have with respect to outstanding warrants for the purchase of the
Registrant common stock and, at the Merger Closing, to surrender their
warrants for termination and cancellation.

          (4)     Boston University agrees to accept the right to receive the
Merger Consideration as satisfaction of all claims that it may have for fees
and other amounts payable to it under the Service Agreement between Marathon
and the Registrant for the period from February 14, 1997, through December 31,
1997.

                                      7
<PAGE>
          (5)     Marathon agrees to accept the right to receive the Merger
Consideration as satisfaction of all claims that it may have for fees and
other amounts payable to it under the Service Agreement between Marathon and
the Registrant for the period from December 31, 1997, through the Merger
Closing.

          (6)     United States Surgical Corporation agrees to accept the
right to receive the Merger Consideration as satisfaction of all claims that
it may have under the July 31, 1997 Evaluation License and Option Agreement
between the Registrant and United States Surgical Corporation and, in
connection therewith, agrees to the termination of such agreement as of the
Merger Closing.

          (7)     Reed Prior, Jean Nichols, Elizabeth Chen and Robert Crane
agree to accept the right to receive the Merger Consideration as satisfaction
of all claims that they may have under their respective employment agreements
to receive asset value realization bonus payments in connection with the
merger transaction.  In addition, they agree to accept the right to receive
the Merger Consideration as satisfaction of all claims that they may have
under non-qualified stock options granted to them by the Registrant and, at
the Merger Closing, to surrender their non-qualified stock options for
termination and cancellation.

          (8)     Lehman Brothers Inc. and Shoreline Pacific agreed to accept
the right to receive the Merger Consideration as satisfaction of all claims
that they may have to fees in respect of the merger transaction.

Each of the parties to the Accord Agreement that is allocated Merger
Consideration under the Merger Agreement is referred to herein as a "Third
Party."  The Registrant covenants not to alter the terms of the Merger
Agreement relating to the allocation of Merger Consideration or otherwise
adversely affecting the rights of any Third Party without the written consent
of all of the Third Parties.

          Each of the Third Parties releases the Registrant and STI and their
current and past directors, officers, employees, agents, representatives,
successors and assigns from any and all claims relating to any act, omission
or circumstance through the date of the Accord Agreement.  The release will
not, however, extend to claims under the Merger Agreement or the Accord
Agreement, to claims for directors' or officers' indemnification, or to claims
for unpaid salary, reimbursable business expenses, employee benefits, or the
like.  The release becomes effective only upon the Merger Closing.

          The Accord Agreement will terminate only upon the termination of the
Merger Agreement.

          Until the termination of the Accord Agreement, each of the parties
thereto agrees to forbear from exercising any right or remedy that is the
subject of the Accord Agreement or any stock option or warrant that any such
party may hold.

                                      8
<PAGE>
          Each of the parties to the Accord Agreement gives certain
representations and warranties regarding its right and authority to enter into
the Accord Agreement.

          Marathon and the other affiliates of Boston University that are
parties to the Marathon Purchase Agreement (the "BU Parties") represent and
warrant that each of the representations and warranties made by the BU Parties
in the Marathon Purchase Agreement are true and correct and agree to comply
with the terms of the Marathon Purchase Agreement through the date of the
Merger Closing.

          Each of the Third Parties other than Lehman Brothers Inc. and
Shoreline Pacific agree to indemnify the BU Parties against claims made
against them pursuant to certain representations and warranties made by the BU
Parties in the Marathon Purchase Agreement through the Merger Closing, but
only to the extent such claims arise as a result of or relate to matters not
known to Kenneth G. Condon or other officers of Boston University or its
subsidiaries other than Marathon, up to $1,000,000 in the aggregate.


          Marathon Purchase Agreement

          Under the Marathon Purchase Agreement, Ligand has an option to
purchase Marathon's assets after the Merger Closing, and is obligated to do so
on January 31, 1999, unless the merger has not closed, in which case either
the Registrant and Ligand may extend the closing date subject to certain
conditions, as described below in the summary of the Extension Option
Agreement.  Upon the closing of the purchase of Marathon's assets by Ligand
(the "Marathon Closing"), Ligand will purchase substantially all of Marathon's
assets other than cash and assume certain limited liabilities.  

          In consideration for Marathon's grant to Ligand of the option to
consummate the Marathon Closing prior to January 31, 1999, Ligand agrees to
pay Marathon $3,000,000 in cash or Ligand common stock, at Ligand's option, if
and when the Milestone Consideration is paid under the Merger Agreement.  Upon
the Marathon Closing, Ligand agrees to pay Marathon an additional $5,000,000
in cash or Ligand common stock.  Any stock delivered as part of such
consideration will be valued on a trailing average market price for the ten
trading days prior to issuance.

          The BU Parties provide certain representations and warranties
regarding Marathon's business, financial condition, and assets.  In general,
representations and warranties by Marathon are given as of the date of the
Marathon Purchase Agreement and as of the date of the Merger Closing.  Certain
limited representations and warranties also are given by Marathon as of the
date of the Marathon Closing.  

          A number of covenants apply to Marathon's conduct of its business
between the date of the Marathon Purchase Agreement and the Marathon Closing. 
These covenants require Marathon, among other things, to carry on its business
only in the usual and ordinary course and impose restrictions on, among other
things, Marathon's ability to dispose of assets, enter into licenses of its
intellectual property, satisfy payables otherwise in the ordinary course, or
increase employee compensation.  

                                      9
<PAGE>
          The Marathon Purchase Agreement may be terminated by either Marathon
or Ligand if, among other things, the other party breaches its obligations
under the Marathon Purchase Agreement and such breach is not promptly cured,
or the other party becomes insolvent or seeks protection under the bankruptcy
laws.  


          Extension Option Agreement

          The Extension Option Agreement permits either Ligand or the
Registrant to extend the term of the Merger Agreement, the Marathon Purchase
Agreement and the Service Agreement past January 31, 1999.

          Under the Extension Option Agreement, Ligand will have the first
right to extend the term of the agreements for one or more additional sixty-
day periods.  If, with respect to the initial term or any extension period,
Ligand declines to extend the agreements, Ligand's option will terminate. 
Thereafter, the Registrant will have the sole right to extend the agreements
for one or more additional sixty-day periods, subject to the approval of the
BU Parties.  

          Marathon and the Registrant are obligated to perform their
respective obligations under the Service Agreement during any extension
period; however, the party that elected to extend the agreements during such
period will be responsible for all "Operating Losses" incurred, and will
benefit from any "Cash Revenue" generated, by Marathon during such period, as
such terms are defined in the Extension Option Agreement, subject to certain
limitations.

          The Extension Option Agreement will terminate if, with respect to
the expiration of the initial term or an extension period, neither the
Registrant nor Ligand elects to extend the Merger Agreement and Marathon
Purchase Agreement.


Assignment of Lilly Agreements

          In connection with the execution and delivery of the Merger
Agreement, the Registrant, Ligand and Lilly entered into an agreement
providing Lilly with the right to assign all of its rights and obligations
under the Sales and Distribution Agreement, dated August 3, 1994, as amended,
and the Development Agreement, dated August 3, 1994, as amended, both between
the Registrant and Lilly, to Ligand (a) upon the consummation of the
transactions contemplated by the Merger Agreement or, (b) prior to the
consummation of the transactions contemplated by the Merger Agreement, in the
event that all authorizations by the appropriate governmental entities
necessary for commercial sale of the Registrant's DAB389IL-2 product
(including exports) in a jurisdiction, including approval of labeling, price,
reimbursement and manufacturing, are obtained, so long as Ligand is in

                                      10
<PAGE>
compliance with its obligations to use its best efforts to satisfy the
conditions to the Registrant's obligations to consummate the transactions
contemplated by the Merger Agreement at the time the relevant governmental
authorizations are obtained.  In addition, Lilly and the Registrant agreed
that the milestone payment required to be made by Lilly to the Registrant
under the Sales and Distribution Agreement will be (a) due upon FDA approval
of DAB389IL-2, rather than sixty days thereafter, and (b) reduced in amount.

                               * * * * * *

          The summaries set forth above are qualified in their entirety by
reference to the documents attached hereto as exhibits.  Readers of this
report on Form 8-K are advised to refer to such exhibits for complete
information regarding the matters addressed herein.


Safe Harbor Information

          Some of the statements contained in this document are forward-
looking, including statements relating directly or by implication to the
Registrant's products, the prospects of regulatory approval for the
Registrant's products, and the Registrant's ability to fund its operations or
to consummate the transactions contemplated by the agreements described
herein.  These statements are based on current expectations and involve a
number of uncertainties and risks, including, but not limited to, the
Registrant's ability to proceed with successful development, testing, and
licensing of its products, the Registrant's ability to continue to fund its
operations, and the Registrant's ability to consummate the transactions
contemplated by the agreements described herein.  For further information,
refer to the "Business Outlook" section in the Registrant's Form 10-K as filed
with the Securities and Exchange Commission.  Actual results may vary
materially from such expectations.  


ITEM 7.  Exhibits

99.1          The Registrant's joint press release with Ligand Pharmaceuticals
              Incorporated, dated May 11, 1998 (filed herewith)

99.2          Settlement Agreement, dated as of May 1, 1998, between the
              Registrant, Seragen Biopharmaceuticals Ltd./Seragen
              Biopharmaceutique Ltee, and the Investor Shareholders named
              therein (filed herewith)

99.3          Agreement and Plan of Reorganization, dated May 11, 1998,
              between the Registrant, Ligand Pharmaceuticals Incorporated, and
              Knight Acquisition Corporation (filed herewith) (1) (2)

                                      11
<PAGE>
99.4          Accord and Satisfaction Agreement, dated May 11, 1998, between
              the Registrant, Seragen Technology, Inc., the Third Parties
              named therein, 520 Commonwealth Avenue Real Estate Corporation,
              and 660 Corporation (filed herewith)

99.5          Extension Option Agreement, dated May 11, 1998, between the
              Registrant, Ligand Pharmaceuticals Incorporated, Marathon
              Biopharmaceuticals LLC, 520 Commonwealth Real Estate
              Corporation, and 660 Corporation (filed herewith)

99.6          Letter agreement, dated May 11, 1998, between the Registrant,
              Ligand Pharmaceuticals Incorporated, and Eli Lilly and Company
              (filed herewith)

                                        

(1)      Confidential treatment has been requested for portions of this
         exhibit, which portions have been omitted form the attached exhibit
         and filed seperately with the Commission.
        
(2)      The schedules referenced in this agreement have not been included
         because they are either disclosed in the agreement or do not contain
         information which is material to an investment decision.  The
         Registrant agrees to furnish to the Commission a copy of such
         schedules upon request.


                                      12
<PAGE>
                            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.

                                             SERAGEN, INC.
                                             (Registrant)




Date: May 14, 1998                           /s/ Reed R. Prior                
                                             __________________
                                             Reed R. Prior
                                             Chairman of the Board and
                                             Chief Executive Officer





                                      14
<PAGE>
[{"type": "8-K", "sequence": "1", "description": "SERAGEN INC", "secsgml_size_bytes": 38475}]
{"company-data": {"conformed-name": "SERAGEN INC", "cik": "0000833299", "assigned-sic": "2836", "irs-number": "042662345", "state-of-incorporation": "DE", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "8-K", "act": "34", "file-number": "000-19855", "film-number": "98621686"}, "business-address": {"street1": "97 SOUTH ST", "city": "HOPKINTON", "state": "MA", "zip": "01748", "phone": "5084352331"}, "mail-address": {"street1": "97 SOUTH ST", "city": "HOPKINTON", "state": "MA", "zip": "01748"}}
UNITED STATES
                SECURITIES AND EXCHANGE COMMISSION

                      Washington, DC  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): May 11, 1998

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

  DELAWARE                      0-19855                 04-2662345       
(State or other               (Commission              (IRS Employer
jurisdiction of               File Number)             Identification No.)
incorporation)

        97 South Street, Hopkinton, Massachusetts  01748   
       (Address of principal executive offices) (Zip Code)

Registrant's telephone number, including area code:  (508) 435-2331
Item 5.  Other Events.

Settlement Agreement

          Effective as of May 1, 1998, the Registrant entered into a
Settlement Agreement (the "Seragen Canada Settlement Agreement") with its
Canadian affiliate, Seragen Biopharmaceuticals Ltd./Seragen Biopharmaceutique
Ltee ("Seragen Canada"), and Sofinov Societe Financiere d'Innovation Inc.,
Societe Inovatech du Grand Montreal, MDS Health Ventures Inc., Canadian
Medical Discoveries Fund Inc., Royal Bank Capital Corporation, and Health Care
and Biotechnology Venture Fund (collectively, the "Investor Shareholders"). 
The Seragen Canada Settlement Agreement provides for the purchase by Seragen
Canada of all shares of Seragen Canada capital stock currently held by the
Investor Shareholders for an aggregate amount equal to Seragen Canada's cash
and liquid investments on hand after the payment of specified expenses.  As of
February 28, 1998, Seragen Canada held approximately $9,400,000 in cash and
liquid investments.  Such purchase transaction is expected to occur on or
prior to June 15, 1998.  Upon the consummation of Seragen Canada's purchase of
the Investor Shareholders' Seragen Canada shares, mutual releases among the
Registrant, Seragen Canada, and the Investor Shareholders will become
effective and a November 22, 1995 Shareholders Agreement and other specified
agreements executed in connection with the original organization of Seragen
Canada in November 1995 will be terminated.  The Seragen Canada Settlement
Agreement also provides for issuance by the Registrant of an aggregate of
$2,400,000 worth of its common stock upon the later to occur of (a) the
closing date for Seragen Canada's purchase of the Investor Shareholders'
Seragen Canada shares and (b) the earliest to occur of (i) an offering by the
Registrant of additional shares of its capital stock with net proceeds to the
Registrant of $10,000,000, (ii) the consummation of a disposition of the
Registrant, whether by way of a merger or otherwise, or substantially all of
the Registrant's assets, and (iii) January 31, 1999, subject to certain
qualifications.  The Investor Shareholders are accorded certain registration
rights with respect to the shares of the Registrant's common stock to be
issued to them.  

Agreement to be Acquired

          On May 11, 1998, the Registrant entered into an Agreement and Plan
of Reorganization (the "Merger Agreement") with Ligand Pharmaceuticals
Incorporated ("Ligand") and its wholly-owned special purpose subsidiary Knight
Acquisition Corporation ("Merger Sub").  The Merger Agreement provides for the
merger, subject to approval by the Registrant's shareholders entitled to vote
thereon, of Merger Sub into the Registrant with the result that the Registrant
will become a wholly-owned subsidiary of Ligand.  In connection with the
execution and delivery of the Merger Agreement, shareholders of the Registrant
holding between 55 and 59 percent of the voting power of the Registrant's
outstanding voting capital stock, including all officers and directors of the
Registrant, entered into agreements with Ligand, which agreements are
supported by irrevocable proxies, to vote their shares in favor of the
transactions contemplated by the Merger Agreement and against competing
proposals. 

                                      1
In connection with the execution and delivery of the Merger
Agreement, the Registrant and its subsidiary Seragen Technology, Inc. ("STI")
entered into an Accord and Satisfaction Agreement, dated as of May 11, 1998
(the "Accord Agreement"), with certain creditors and preferred shareholders of
the Registrant.  Pursuant to the Accord Agreement, the parties thereto other
than the Registrant and STI agreed to accept merger consideration allocated to
them pursuant to the Merger Agreement as full and complete satisfaction of
certain of their rights and claims against the Registrant and STI. 

          Simultaneously with the execution and delivery of the Merger
Agreement, Ligand entered into an Option and Asset Purchase Agreement, dated
May 11, 1998 (the "Marathon Purchase Agreement"), with Marathon
Biopharmaceuticals LLC ("Marathon"), 520 Commonwealth Avenue Real Estate
Corporation ("520 Commonwealth"), and 660 Corporation ("660 Corp.") providing
for the purchase by Ligand of substantially all of the assets of Marathon on
or before January 31, 1999, but in any event not earlier than the closing of
the transactions contemplated by the Merger Agreement.  Marathon provides
manufacturing, clinical trial, and product research and development services
to the Registrant pursuant to a Service Agreement, dated as of February 14,
1997, as amended (the "Service Agreement"), between the Registrant and
Trustees of Boston University.

          In connection with the execution and delivery of the Merger
Agreement and the Marathon Purchase Agreement, the Registrant, Ligand,
Marathon, 520 Commonwealth, and 660 Corp. entered into an Extension Option
Agreement, dated May 11, 1998 (the "Extension Option Agreement"), providing
each of the Registrant and Ligand with the right to extend the termination
dates of the Merger Agreement and the Marathon Purchase Agreement in certain
circumstances. 
          
          The Registrant and Ligand issued a joint press release on May 11,
1998, announcing the signing of the Merger Agreement and related agreements. 
A copy of the press release is included as an exhibit hereto.

          Merger Agreement  

          The Merger Agreement provides for Merger Sub to be merged into the
Registrant, with the Registrant as the surviving corporation in the merger
(the "Surviving Corporation").  In connection with the consummation of the
merger (the "Merger Closing"), Ligand will deliver cash and shares of its
common stock to the shareholders and certain creditors of the Registrant,
thereby extinguishing the interest of the Registrant's existing shareholders
in the Registrant.  At the same time, the shares of the Merger Sub will be
converted into shares of the Surviving Corporation, with the result that the
Surviving Corporation will be a wholly-owned subsidiary of Ligand following
the Merger Closing.  Existing shareholders of the Registrant who dissent from
the merger transaction may, under Delaware law, pursue appraisal rights if
they so choose.  

                                      2
The Merger Agreement provides for a total payment by Ligand to the
Registrant's shareholders and creditors of $67,000,000, with a portion of this
amount payable only upon certain conditions, as described below.  Of this,
Ligand will pay $30,000,000 at the Merger Closing, payable in the form of cash
in the amount of $4,000,000 and shares of Ligand common stock in the amount of
$26,000,000 (the "Closing Consideration").  The cash portion of the Closing
Consideration will be used primarily to satisfy accounts payable and certain
other obligations of the Registrant.  Ligand may, at its option, increase the
amount of cash payable at the Merger Closing to satisfy certain of the
Registrant's payables, in which case the amount of stock consideration
included in the Closing Consideration will be correspondingly reduced.  The
shares of Ligand common stock to be delivered by Ligand at the Merger Closing
will be valued at $13.9875 per share, which is based on the trailing average
market price for the five trading days prior to May 11, 1998, the date on
which the Merger Agreement was executed.

          The remaining $37,000,000 of the merger consideration (the
"Milestone Consideration"; the Closing Consideration and Milestone
Consideration together, the "Merger Consideration") will be paid by Ligand six
months following the receipt by the Surviving Corporation of FDA approval for
the marketing, distribution and selling of DAB389IL-2 in the United States for
CTCL if such approval is supported to any material extent by clinical and
development efforts of the Registrant prior to the consummation of the merger. 
The Milestone Consideration will, however, only be payable by Ligand if the
required FDA approval is obtained within two years of the Merger Closing;
otherwise, Ligand is relieved of any obligation to pay the Milestone
Consideration.  Ligand may pay the Milestone Consideration in the form of cash
or Ligand common stock or a combination thereof.  Any stock delivered as part
of the Milestone Consideration will be valued on a trailing average market
price for the ten trading days prior to issuance.

          Ligand has agreed to take certain steps following the consummation
of the merger to facilitate the required approval of DAB389IL-2.  Those steps
include, among other things, the conduct of certain additional tests and
studies necessary to obtain such approval, and the avoidance of any changes in
the operations, personnel and facilities of Marathon if such changes could be
expected to adversely affect the prospects for FDA approval.  More generally,
Ligand has agreed to use commercially reasonable efforts to take all actions
after the Merger Closing that are necessary or appropriate to obtain the
required FDA approval of DAB389IL-2 by the second anniversary of the Merger
Closing.

          The Merger Consideration is to be distributed first to the holders
of Registrant's common stock and Series D preferred stock, next to certain
creditors of the Registrant, and finally to the preferred shareholders and
certain other creditors of the Registrant, all as set forth in Section 1.7 of
the Merger Agreement.  The holders of the Registrant's common stock and Series
D preferred stock are entitled to receive for each share of Registrant common
stock (for purposes of this distribution, shares of Series D preferred stock
will be deemed to have been converted into the number of shares of common
stock of the Registrant that such shares of Series D preferred stock would
have been converted into had the conversion been effected immediately prior to
the effective date of the merger) (a) in connection with the Merger Closing,

                                      3
0.035746 shares of common stock of Ligand and, (b) if and only if the
Milestone Consideration is paid, cash or Ligand stock, as applicable, valued
at $0.23.  

          Certain creditors and obligees of the Registrant, including United
States Surgical Corporation and, to the extent of amounts payable by the
Registrant pursuant to the Service Agreement, Boston University and Marathon,
are entitled to receive a fixed amount of Merger Consideration in satisfaction
of the Registrant's obligations to such creditors and obligees.  The holders
of the Registrant's Series B preferred shares, the Registrant's executive
officers, and the Registrant's financial advisers will receive the amount of
Merger Consideration remaining after the distribution to the holders of the
Registrant's common stock and Series D preferred stock and the satisfaction of
the Registrant's financial obligations as of the Merger Closing.  These
distribution arrangements are reflected in Section 1.7 of the Merger
Agreement. 

          Ligand common stock to be delivered as part of the Merger
Consideration is required to be registered under federal securities laws so as
to permit immediate resale of the shares, subject to prospectus delivery
requirements under applicable SEC rules and certain trading volume limitations
that may be applicable under the SEC's Rule 145.  Boston University will be
prohibited from transferring Ligand common shares that it receives in the
merger until the later of the second anniversary of the Merger Closing and the
first anniversary of the issuance of such shares.  The restrictions described
in the foregoing sentence will not, however, apply to the Ligand common
shares, if any, that Boston University receives in respect of approximately
$5,900,000 owed to it and Marathon by the Registrant under the Service
Agreement between the Registrant and Marathon.  Executive officers of the
Registrant and the Registrant's financial advisers, Lehman Brothers Inc. and
Shoreline Pacific Institutional Finance ("Shoreline Pacific"), will be
prohibited from transferring 50 percent and 100 percent, respectively, of the
Ligand common shares that they receive in the merger until the ninetieth day
following issuance.  The right of Eli Lilly and Company ("Lilly") to transfer
Ligand common shares that it receives as Merger Consideration will be
restricted to the same extent as Ligand common shares previously issued to
Lilly by Ligand.
 
          The Registrant provides certain representations and warranties
regarding its business, financial condition, and assets.  In general,
representations and warranties given by the Registrant are given both as of
the date of the Merger Agreement and as of the date of the Merger Closing.  

          Ligand provides certain representations and warranties regarding its
business, financial condition, and assets.  In general, representations and
warranties given by Ligand relating to its business and financial condition
are given only as of the date of the Merger Agreement; representations and
warranties given by Ligand relating to its ability to consummate the Merger
Closing, such as the legal existence and authority of Ligand and Merger Sub,
are given both as of the date of the Merger Agreement and the date of the
Merger Closing.  

                                      4
A number of covenants apply to the Registrant's conduct of its
business between the date of the Merger Agreement and the Merger Closing. 
These covenants require the Registrant, among other things, to carry on its
business only in the usual and ordinary course and impose restrictions on,
among other things, the Registrant's ability to dispose of assets, enter into
licenses of its intellectual property, satisfy payables other than in the
ordinary course, or increase employee compensation.

          A $200,000 cash portion of the Closing Consideration will be placed
in escrow with State Street Bank and Trust Company.  In addition, revenues
received by the Surviving Corporation after the Merger Closing that are
attributable to the operation of the Registrant prior to the Merger Closing
will be deposited in the escrow account.  The escrow account will be used to
pay certain obligations of the Surviving Corporation that are attributable to
the operation of the Registrant prior to the Merger Closing.  Any amounts
remaining in the escrow account on the 120th day after the Merger Closing will
be distributed as additional Closing Consideration to those persons receiving
variable amounts of Closing Consideration under the Merger Agreement.  

          The obligations of the Registrant, on the one hand, and Ligand and
Merger Sub, on the other hand, to proceed with the consummation of the Merger
are conditioned, among other things, upon the approval of the merger by the
Registrant's stockholders, the receipt of required government approvals
(including clearance under the Hart-Scott-Rodino Antitrust Improvements Act)
and the effectiveness of Ligand's registration statement relating to the
Ligand common shares to be issued as Merger Consideration.  In addition, the
approval of the transaction by the Public Charities Division of the
Massachusetts Attorney General's office must be in full force and effect.  The
Registrant's obligations to consummate the merger are further conditioned on,
among other things, the accuracy of Ligand's representations and warranties as
of the date given and the satisfaction by Ligand of certain obligations to be
satisfied by it by the Merger Closing.  Ligand's obligation to consummate the
merger is further conditioned on, among other things, the accuracy of the
Registrant's representations and warranties as of the date given, the
satisfaction by the Registrant of obligations to be satisfied by it by the
Merger Closing, the absence of any general adverse development in the
Registrant's business (other than an adverse development relating to the FDA's
review of DAB389IL-2) resulting in a diminution of the value of the Registrant
by $5,000,000 or more, the accuracy of Marathon's representations and
warranties contained in the Marathon Purchase Agreement, the satisfaction by
Marathon of all obligations to be satisfied by it pursuant to the Marathon
Purchase Agreement by the Merger Closing, and no more than ten percent of the
Registrant's outstanding capital stock being the subject of dissenters' or
appraisal rights under Delaware law. 

          The Registrant has agreed that it will not take any action to
solicit or encourage a competing proposal; however, the board of the
Registrant may engage in negotiations with, or disclose any nonpublic
information relating to the Registrant or afford access to the properties,
books or records of the Registrant to, any person or entity that informs the
Registrant that it is considering making, or has made, a competing proposal.

                                      5
The Merger Agreement may be terminated by either the Registrant or
Ligand if the Merger Closing has not occurred by January 31, 1999.  However,
each of the Registrant and Ligand is provided with an option to extend this
expiration date subject to certain conditions, as described below in the
summary of the Extension Option Agreement.  In addition, the Merger Agreement
may be terminated by either the Registrant or Ligand if, among other things, a
final court order is entered prohibiting the merger, the Registrant's
stockholders at a meeting of the Registrant's stockholders fail to approve the
merger or approve a competing proposal, the other party breaches its
obligations under the Merger Agreement and such breach is not promptly cured,
or the other party becomes insolvent or seeks protection under the bankruptcy
laws.  Ligand also may terminate the Merger Agreement in the event any court
order or applicable law would prohibit Ligand from owning its assets and the
assets of the Registrant following the Merger Closing, in the event of an
occurrence of any general adverse development in the Registrant's business
(other than an adverse development relating to the FDA's review of DAB389IL-2)
resulting in a diminution of the value of the Registrant by $5,000,000 or
more, if any person purchases a majority of the Registrant's common stock, or
if the Registrant's board of directors withdraws its recommendation in favor
of the merger.  The Registrant may terminate the Merger Agreement if it
receives a competing proposal that the Registrant's board determines, after
consultation with counsel, to recommend to the Registrant's stockholders in
order to comply with the fiduciary duty of the board.

          Ligand is provided with the right to set off against Merger
Consideration payable to those persons receiving variable amounts of Merger
Consideration any damages that it may incur as a result of a breach of the
Registrant's representations, warranties or covenants under the Merger
Agreement.  However, Ligand may pursue such a set off only to the extent its
damages exceed an aggregate of $250,000, and in no event may the amount of set
off exceed an aggregate of $2,900,000.  Above the set off amount, Ligand is
permitted to pursue claims against persons receiving variable amounts of
Merger Consideration for damages as aforesaid, but only up to an amount of
$8,700,000.  Ligand is prohibited from pursuing claims under the Merger
Agreement against the Registrant common shareholders and from recovering
Merger Consideration paid to the Registrant common shareholders.  Ligand is
prohibited from pursuing claims under the Registrant's representations,
warranties and covenants of which it has not given notice prior to their
termination.  Except for certain representations and warranties relating to
matters of the Registrant's ability to validly consummate the merger and tax
matters, which survive, respectively, indefinitely and until the expiration of
the applicable statute of limitations, the Registrant's representations,
warranties and covenants under the Merger Agreement expire on the third
anniversary of the Merger Closing.

          In the event that Ligand terminates the Merger Agreement because of
a bankruptcy or the Registrant terminates the agreement because it has
received a competing proposal that the Registrant's board determines, after
consultation with counsel, to recommend to the Registrant's stockholders in
order to comply with its fiduciary duty, the Registrant is obligated to pay
Ligand a fee equal to $5,000,000 plus five percent of any additional value,
over the $67,000,000 contemplated by the Merger Agreement, realized by the
Registrant or its stockholders in connection with the consummation of a
competing acquisition proposal.  Such fee is, in addition, to be increased by
any Marathon losses assumed by Ligand in connection with its exercise of its
option under the Extension Option Agreement (described below) to extend the
term of the Merger Agreement beyond January 31, 1999.

          Ligand is required to maintain the Registrant's existing directors
and officers insurance policy in effect for the remainder of its term and, for
one year after the expiration of such policy, to use reasonable efforts either
to extend such policy or to cause current directors and officers of the
Registrant to be covered by directors and officers insurance comparable to
that maintained for Ligand's directors.  In addition, Ligand is required to

                                      6
cause the Surviving Corporation to maintain the Registrant's existing
indemnification obligations in effect for the benefit of current and past
directors and officers of the Registrant.

          Accord Agreement

          The Accord Agreement provides that the signatories other than the
Registrant and STI will accept the amount of Merger Consideration allocated to
them in the Merger Agreement as full and complete satisfaction for their
specified claims against the Registrant, as follows:

          (1)     Boston University, Leon Hirsch, Turi Josefsen, and Gerald
and Loretta Cassidy agree to accept the right to receive the Merger
Consideration as satisfaction of all claims that they may have with respect to
the Registrant's outstanding Series B preferred stock and, at the Merger
Closing, to surrender their shares of Series B preferred stock for termination
and cancellation.

          (2)     Boston University agrees to accept the right to receive the
Merger Consideration as satisfaction of all claims that it may have to a cash
payment in the amount of $4,600,000 arising from the automatic conversion of
the Registrant's outstanding Series C preferred stock that occurred on March
30, 1998 and agrees to surrender immediately prior to the effective time of
the merger, without additional compensation, to the Registrant for
cancellation the 3,360,625 shares of the Registrant's common stock that it
received in connection with the March 30, 1998 conversion of the Registrant's
outstanding Series C preferred stock.

          (3)     Boston University, Leon Hirsch, Turi Josefsen, Gerald and
Loretta Cassidy, and United States Surgical Corporation agree to accept the
right to receive the Merger Consideration as satisfaction of all claims that
they may have with respect to outstanding warrants for the purchase of the
Registrant common stock and, at the Merger Closing, to surrender their
warrants for termination and cancellation.

          (4)     Boston University agrees to accept the right to receive the
Merger Consideration as satisfaction of all claims that it may have for fees
and other amounts payable to it under the Service Agreement between Marathon
and the Registrant for the period from February 14, 1997, through December 31,
1997.

                                      7
(5)     Marathon agrees to accept the right to receive the Merger
Consideration as satisfaction of all claims that it may have for fees and
other amounts payable to it under the Service Agreement between Marathon and
the Registrant for the period from December 31, 1997, through the Merger
Closing.

          (6)     United States Surgical Corporation agrees to accept the
right to receive the Merger Consideration as satisfaction of all claims that
it may have under the July 31, 1997 Evaluation License and Option Agreement
between the Registrant and United States Surgical Corporation and, in
connection therewith, agrees to the termination of such agreement as of the
Merger Closing.

          (7)     Reed Prior, Jean Nichols, Elizabeth Chen and Robert Crane
agree to accept the right to receive the Merger Consideration as satisfaction
of all claims that they may have under their respective employment agreements
to receive asset value realization bonus payments in connection with the
merger transaction.  In addition, they agree to accept the right to receive
the Merger Consideration as satisfaction of all claims that they may have
under non-qualified stock options granted to them by the Registrant and, at
the Merger Closing, to surrender their non-qualified stock options for
termination and cancellation.

          (8)     Lehman Brothers Inc. and Shoreline Pacific agreed to accept
the right to receive the Merger Consideration as satisfaction of all claims
that they may have to fees in respect of the merger transaction.

Each of the parties to the Accord Agreement that is allocated Merger
Consideration under the Merger Agreement is referred to herein as a "Third
Party."  The Registrant covenants not to alter the terms of the Merger
Agreement relating to the allocation of Merger Consideration or otherwise
adversely affecting the rights of any Third Party without the written consent
of all of the Third Parties.

          Each of the Third Parties releases the Registrant and STI and their
current and past directors, officers, employees, agents, representatives,
successors and assigns from any and all claims relating to any act, omission
or circumstance through the date of the Accord Agreement.  The release will
not, however, extend to claims under the Merger Agreement or the Accord
Agreement, to claims for directors' or officers' indemnification, or to claims
for unpaid salary, reimbursable business expenses, employee benefits, or the
like.  The release becomes effective only upon the Merger Closing.

          The Accord Agreement will terminate only upon the termination of the
Merger Agreement.

          Until the termination of the Accord Agreement, each of the parties
thereto agrees to forbear from exercising any right or remedy that is the
subject of the Accord Agreement or any stock option or warrant that any such
party may hold.

                                      8
Each of the parties to the Accord Agreement gives certain
representations and warranties regarding its right and authority to enter into
the Accord Agreement.

          Marathon and the other affiliates of Boston University that are
parties to the Marathon Purchase Agreement (the "BU Parties") represent and
warrant that each of the representations and warranties made by the BU Parties
in the Marathon Purchase Agreement are true and correct and agree to comply
with the terms of the Marathon Purchase Agreement through the date of the
Merger Closing.

          Each of the Third Parties other than Lehman Brothers Inc. and
Shoreline Pacific agree to indemnify the BU Parties against claims made
against them pursuant to certain representations and warranties made by the BU
Parties in the Marathon Purchase Agreement through the Merger Closing, but
only to the extent such claims arise as a result of or relate to matters not
known to Kenneth G. Condon or other officers of Boston University or its
subsidiaries other than Marathon, up to $1,000,000 in the aggregate.

          Marathon Purchase Agreement

          Under the Marathon Purchase Agreement, Ligand has an option to
purchase Marathon's assets after the Merger Closing, and is obligated to do so
on January 31, 1999, unless the merger has not closed, in which case either
the Registrant and Ligand may extend the closing date subject to certain
conditions, as described below in the summary of the Extension Option
Agreement.  Upon the closing of the purchase of Marathon's assets by Ligand
(the "Marathon Closing"), Ligand will purchase substantially all of Marathon's
assets other than cash and assume certain limited liabilities.  

          In consideration for Marathon's grant to Ligand of the option to
consummate the Marathon Closing prior to January 31, 1999, Ligand agrees to
pay Marathon $3,000,000 in cash or Ligand common stock, at Ligand's option, if
and when the Milestone Consideration is paid under the Merger Agreement.  Upon
the Marathon Closing, Ligand agrees to pay Marathon an additional $5,000,000
in cash or Ligand common stock.  Any stock delivered as part of such
consideration will be valued on a trailing average market price for the ten
trading days prior to issuance.

          The BU Parties provide certain representations and warranties
regarding Marathon's business, financial condition, and assets.  In general,
representations and warranties by Marathon are given as of the date of the
Marathon Purchase Agreement and as of the date of the Merger Closing.  Certain
limited representations and warranties also are given by Marathon as of the
date of the Marathon Closing.  

          A number of covenants apply to Marathon's conduct of its business
between the date of the Marathon Purchase Agreement and the Marathon Closing. 
These covenants require Marathon, among other things, to carry on its business
only in the usual and ordinary course and impose restrictions on, among other
things, Marathon's ability to dispose of assets, enter into licenses of its
intellectual property, satisfy payables otherwise in the ordinary course, or
increase employee compensation.  

                                      9
The Marathon Purchase Agreement may be terminated by either Marathon
or Ligand if, among other things, the other party breaches its obligations
under the Marathon Purchase Agreement and such breach is not promptly cured,
or the other party becomes insolvent or seeks protection under the bankruptcy
laws.  

          Extension Option Agreement

          The Extension Option Agreement permits either Ligand or the
Registrant to extend the term of the Merger Agreement, the Marathon Purchase
Agreement and the Service Agreement past January 31, 1999.

          Under the Extension Option Agreement, Ligand will have the first
right to extend the term of the agreements for one or more additional sixty-
day periods.  If, with respect to the initial term or any extension period,
Ligand declines to extend the agreements, Ligand's option will terminate. 
Thereafter, the Registrant will have the sole right to extend the agreements
for one or more additional sixty-day periods, subject to the approval of the
BU Parties.  

          Marathon and the Registrant are obligated to perform their
respective obligations under the Service Agreement during any extension
period; however, the party that elected to extend the agreements during such
period will be responsible for all "Operating Losses" incurred, and will
benefit from any "Cash Revenue" generated, by Marathon during such period, as
such terms are defined in the Extension Option Agreement, subject to certain
limitations.

          The Extension Option Agreement will terminate if, with respect to
the expiration of the initial term or an extension period, neither the
Registrant nor Ligand elects to extend the Merger Agreement and Marathon
Purchase Agreement.

Assignment of Lilly Agreements

          In connection with the execution and delivery of the Merger
Agreement, the Registrant, Ligand and Lilly entered into an agreement
providing Lilly with the right to assign all of its rights and obligations
under the Sales and Distribution Agreement, dated August 3, 1994, as amended,
and the Development Agreement, dated August 3, 1994, as amended, both between
the Registrant and Lilly, to Ligand (a) upon the consummation of the
transactions contemplated by the Merger Agreement or, (b) prior to the
consummation of the transactions contemplated by the Merger Agreement, in the
event that all authorizations by the appropriate governmental entities
necessary for commercial sale of the Registrant's DAB389IL-2 product
(including exports) in a jurisdiction, including approval of labeling, price,
reimbursement and manufacturing, are obtained, so long as Ligand is in

                                      10
compliance with its obligations to use its best efforts to satisfy the
conditions to the Registrant's obligations to consummate the transactions
contemplated by the Merger Agreement at the time the relevant governmental
authorizations are obtained.  In addition, Lilly and the Registrant agreed
that the milestone payment required to be made by Lilly to the Registrant
under the Sales and Distribution Agreement will be (a) due upon FDA approval
of DAB389IL-2, rather than sixty days thereafter, and (b) reduced in amount.

                               * * * * * *

          The summaries set forth above are qualified in their entirety by
reference to the documents attached hereto as exhibits.  Readers of this
report on Form 8-K are advised to refer to such exhibits for complete
information regarding the matters addressed herein.

Safe Harbor Information

          Some of the statements contained in this document are forward-
looking, including statements relating directly or by implication to the
Registrant's products, the prospects of regulatory approval for the
Registrant's products, and the Registrant's ability to fund its operations or
to consummate the transactions contemplated by the agreements described
herein.  These statements are based on current expectations and involve a
number of uncertainties and risks, including, but not limited to, the
Registrant's ability to proceed with successful development, testing, and
licensing of its products, the Registrant's ability to continue to fund its
operations, and the Registrant's ability to consummate the transactions
contemplated by the agreements described herein.  For further information,
refer to the "Business Outlook" section in the Registrant's Form 10-K as filed
with the Securities and Exchange Commission.  Actual results may vary
materially from such expectations.  

ITEM 7.  Exhibits

99.1          The Registrant's joint press release with Ligand Pharmaceuticals
              Incorporated, dated May 11, 1998 (filed herewith)

99.2          Settlement Agreement, dated as of May 1, 1998, between the
              Registrant, Seragen Biopharmaceuticals Ltd./Seragen
              Biopharmaceutique Ltee, and the Investor Shareholders named
              therein (filed herewith)

99.3          Agreement and Plan of Reorganization, dated May 11, 1998,
              between the Registrant, Ligand Pharmaceuticals Incorporated, and
              Knight Acquisition Corporation (filed herewith) (1) (2)

                                      11
99.4          Accord and Satisfaction Agreement, dated May 11, 1998, between
              the Registrant, Seragen Technology, Inc., the Third Parties
              named therein, 520 Commonwealth Avenue Real Estate Corporation,
              and 660 Corporation (filed herewith)

99.5          Extension Option Agreement, dated May 11, 1998, between the
              Registrant, Ligand Pharmaceuticals Incorporated, Marathon
              Biopharmaceuticals LLC, 520 Commonwealth Real Estate
              Corporation, and 660 Corporation (filed herewith)

99.6          Letter agreement, dated May 11, 1998, between the Registrant,
              Ligand Pharmaceuticals Incorporated, and Eli Lilly and Company
              (filed herewith)

                                        

(1)      Confidential treatment has been requested for portions of this
         exhibit, which portions have been omitted form the attached exhibit
         and filed seperately with the Commission.
        
(2)      The schedules referenced in this agreement have not been included
         because they are either disclosed in the agreement or do not contain
         information which is material to an investment decision.  The
         Registrant agrees to furnish to the Commission a copy of such
         schedules upon request.

                                      12
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.

                                             SERAGEN, INC.
                                             (Registrant)

Date: May 14, 1998                           /s/ Reed R. Prior                
                                             __________________
                                             Reed R. Prior
                                             Chairman of the Board and
                                             Chief Executive Officer

                                      14