Document:

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                                                                   EXHIBIT 10.61

                           Nexell Therapeutics Inc.
                                   9 Parker
                           Irvine, California 92618

                                                        As of May 25, 1999
Mr. Donald G. Drapkin
c/o MacAndrews & Forbes
35 East 62nd Street
New York, NY

Re:  Amendment to November 17, 1995 Stock Option Agreement
     -----------------------------------------------------

Dear Mr. Drapkin:

     This letter constitutes an amendment to the Stock Option Agreement dated as
of November 17, 1995 (the "Option Agreement") between you and Nexell
Therapeutics Inc. (formerly named VIMRx Pharmaceuticals Inc.) as follows:

     In consideration of your willingness to extend your consulting services for
a period of three years, the parties hereto acknowledge and agree that the
expiration date of the "Option" (as each of those terms is defined in the Option
Agreement) is extended from November 16, 2000 to November 16, 2003, subject to
approval by the Company's shareholders as required by rules of The NASDAQ Stock
Market, Inc.  In addition, you shall be entitled to a "cashless exercise"
provision consistent with the cashless exercise provision authorized under the
Company's 1997 Incentive and Non-Incentive Stock Option Plan.

     Except as expressly set forth herein, the Option Agreement shall remain in
full force and effect.

     Please sign below in the space provided to signify your consent to the
foregoing amendment.

                                Very truly yours,

                                NEXELL THERAPEUTICS INC.

                                By:  /s/ Richard L. Dunning
                                     ----------------------
                                     Richard L. Dunning
                                     Chairman of the Board and Chief
                                     Executive Officer

I hereby acknowledge and agree to the foregoing amendment.

/s/ Donald G. Drapkin
-------------------------
Donald G. Drapkin<PAGE>

                                                                   EXHIBIT 10.62

                           INDEMNIFICATION AGREEMENT

     This Indemnification Agreement, dated as of November 9, 1999, is made by
and between Nexell Therapeutics Inc., a Delaware corporation (the
"Corporation"), and the person whose name, address and position at the
Corporation and/or any of the direct or indirect subsidiaries of the Corporation
appear on the signature page hereto ("Indemnitee").

                                    RECITALS

     A.  Indemnitee is currently serving as, or is assuming the position of, a
director and/or officer of the Corporation and/or, at the Corporation's request,
a director, officer, employee and/or agent of another corporation, partnership,
joint venture, trust or other enterprise, and the Corporation wishes Indemnitee
to continue in such capacity(ies);

     B.  The Corporation and Indemnitee recognize that the present state of the
law is too uncertain to provide the Corporation's directors and officers with
adequate and reliable advance knowledge or guidance with respect to the legal
risks and potential liabilities to which they may become personally exposed as a
result of performing their duties for the Corporation;

     C.  The Restated Certificate of Incorporation (the "Certificate") and the
Amended and Restated Bylaws (the "Bylaws") of the Corporation each provide that
the Corporation may indemnify, to the fullest extent permitted by law, certain
persons, including directors, officers, employees or agents of the Corporation,
against specified expenses and losses arising out of certain threatened, pending
or completed actions, suits or proceedings;

     D.  Section 145(f) of the Delaware General Corporation Law (the "DGCL")
expressly recognizes that the indemnification provided by the other subsections
of Section 145 of the DGCL shall not be deemed exclusive of any other rights to
which those seeking indemnification or advancement of expenses may be entitled
under any bylaw, agreement, vote of stockholders or disinterested directors or
otherwise, both as to action in an official capacity and as to action in another
capacity while holding such office;

     E.  Indemnitee has indicated that he may not be willing to serve, or
continue to serve, as a director and/or officer of the Corporation and/or, at
the Corporation's request, as a director, officer, employee and/or agent of
another corporation, partnership, joint venture, trust or other enterprise in
the absence of an indemnification agreement of the Corporation;

     F.  The Board of Directors of the Corporation has concluded that, to retain
and attract talented and experienced individuals to serve as directors and
officers of the Corporation and to encourage such individuals to take the
business risks necessary for the success of the Corporation, it is necessary for
the Corporation to contractually indemnify them, and to assume for itself
liability for expenses and damages in connection with claims against them in
connection with their service to the Corporation, and has further concluded that
the failure to provide such contractual indemnification could result in great
harm to the Corporation and its stockholders.

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                                   AGREEMENT

     NOW, THEREFORE, the Corporation and Indemnitee agree as follows:

     1.  Definitions.
         -----------

         (a) "Expenses" means, for the purposes of this Agreement, all direct
and indirect costs of any type or nature whatsoever (including, without
limitation, any fees and disbursements of Indemnitee's counsel, accountants and
other experts and other out-of-pocket costs) actually and reasonably incurred by
Indemnitee in connection with the investigation, preparation, defense or appeal
of a Proceeding; provided, however, that Expenses shall not include judgments,
fines, penalties or amounts paid in settlement of a Proceeding unless such
matters may be indemnified under applicable provisions of the DGCL.

          (b) "Proceeding" means, for the purposes of this Agreement, any
threatened, pending or completed action, suit or proceeding whether civil,
criminal, administrative or investigative (including actions, suits or
proceedings brought by or in the right of the Corporation) in which Indemnitee
may be or may have been involved as a party or otherwise, by reason of the fact
that Indemnitee is or was a director or officer of the Corporation, by reason of
any action taken by him or of any inaction on his part while acting as such
director or officer or by reason of the fact that he is or was serving at the
request of the Corporation as a director, officer, employee or agent of another
foreign or domestic corporation, partnership, joint venture, trust or other
enterprise, or was a director and/or officer of the foreign or domestic
corporation which was a predecessor corporation to the Corporation or of another
enterprise at the request of such predecessor corporation, whether or not he is
serving in such capacity at the time any liability or expense is incurred for
which indemnification or reimbursement can be provided under this Agreement.

     2.  Indemnification.
         ---------------

         (a) Third Party Proceedings.  To the fullest extent permitted by law,
             -----------------------
the Corporation shall indemnify Indemnitee against Expenses and liabilities of
any type whatsoever (including, but not limited to, judgments, fines, penalties,
and amounts paid in settlement (if the settlement is approved in advance by the
Corporation)) actually and reasonably incurred by Indemnitee in connection with
a Proceeding (other than a Proceeding by or in the right of the Corporation) if
Indemnitee acted in good faith and in a manner Indemnitee reasonably believed to
be in, or not opposed to, the best interests of the Corporation, and, with
respect to any criminal action or proceeding, had no reasonable cause to believe
Indemnitee's conduct was unlawful. The termination of any Proceeding by
judgment, order, settlement, conviction, or upon a plea of nolo contendere or
its equivalent, shall not, of itself, create a presumption that Indemnitee did
not act in good faith and in a manner that Indemnitee reasonably believed to be
in, or not opposed to, the best interests of the Corporation, or, with respect
to any criminal Proceeding, had reasonable cause to believe that Indemnitee's
conduct was unlawful. Notwithstanding the foregoing, no indemnification shall be
made in any criminal proceeding where Indemnitee has been adjudged guilty unless
a disinterested majority of the directors determines that Indemnitee did not
receive, participate in or share in any pecuniary benefit to the detriment of
the Corporation and, in view

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of all the circumstances of the case, Indemnitee is fairly and reasonably
entitled to indemnity for Expenses or liabilities.

         (b) Proceedings by or in the Right of the Corporation.  To the fullest
             -------------------------------------------------
extent permitted by law, the Corporation shall indemnify Indemnitee against
Expenses actually and reasonably incurred by Indemnitee in connection with the
defense or settlement of a Proceeding by or in the right of the Corporation to
procure a judgment in its favor if Indemnitee acted in good faith and in a
manner Indemnitee reasonably believed to be in, or not opposed to, the best
interests of the Corporation. Notwithstanding the foregoing, no indemnification
shall be made in respect of any claim, issue or matter as to which Indemnitee
shall have been adjudged to be liable to the Corporation in the performance of
Indemnitee's duty to the Corporation unless and only to the extent that the
court in which such Proceeding is or was pending shall determine upon
application that, in view of all the circumstances of the case, Indemnitee is
fairly and reasonably entitled to indemnity for Expenses and then only to the
extent that the court shall determine.

         (c) Scope.  Notwithstanding any other provision of this Agreement
             -----
other than Sections 3 and 13, the Corporation shall indemnify Indemnitee to the
fullest extent permitted by law, notwithstanding that such indemnification is
not specifically authorized by other provisions of this Agreement, the
Certificate, the Bylaws or statute.

     3.  Limitations on Indemnification.  Any other provision herein to the
         ------------------------------
contrary notwithstanding, the Corporation shall not be obligated pursuant to the
terms of this Agreement:

         (a) Excluded Acts.  To indemnify Indemnitee for any acts or omissions
              -------------
or transactions from which a director may not be relieved of liability under
Section 102(b)(7) of the DGCL; or

         (b) Claims Initiated by Indemnitee.  To indemnify or advance Expenses
             ------------------------------
to Indemnitee with respect to Proceedings or claims initiated or brought
voluntarily by Indemnitee and not by way of defense, except with respect to
proceedings brought to establish or enforce a right to indemnification under
this Agreement or any other statute or law or otherwise as required under
Section 145 of the DGCL, but such indemnification or advancement of Expenses may
be provided by the Corporation in specific cases if a majority of the
disinterested directors has approved the initiation or bringing of such suit; or

         (c) Lack of Good Faith.  To indemnify Indemnitee for any Expenses
             ------------------
incurred by Indemnitee with respect to any proceeding instituted by Indemnitee
to enforce or interpret this Agreement, if a court of competent jurisdiction
determines that each of the material assertions made by Indemnitee in such
proceeding was not made in good faith or was frivolous; or

         (d) Insured Claims.  To indemnify Indemnitee for Expenses or
             --------------
liabilities of any type whatsoever (including, but not limited to, judgments,
fines or penalties, and amounts paid in settlement) which have been paid
directly to or on behalf of Indemnitee by an insurance carrier under a policy of
directors' and officers' liability insurance maintained by the Corporation or
any other policy of insurance maintained by the Corporation or Indemnitee; or

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         (e) Claims Under Section 16(b).  To indemnify Indemnitee for Expenses
             --------------------------
and the payment of profits arising from the purchase and sale by Indemnitee of
securities in violation of Section 16(b) of the Securities Exchange Act of 1934,
as amended, or any similar successor statute.

     4.  Determination of Right to Indemnification.  Upon receipt of a written
         -----------------------------------------
claim addressed to the Board of Directors for indemnification pursuant to
Section 2 of this Agreement, the Corporation shall determine by any of the
methods set forth in Section 145(d) of the DGCL whether Indemnitee has met the
applicable standards of conduct that make it permissible under applicable law to
indemnify Indemnitee. If a claim under Section 2 of this Agreement is not paid
in full by the Corporation within ninety days after such written claim has been
received by the Corporation, Indemnitee may at any time thereafter bring suit
against the Corporation to recover the unpaid amount of the claim and, unless
such action is dismissed by the court as frivolous or brought in bad faith,
Indemnitee shall be entitled to be paid also the expense of prosecuting such
claim. Neither the failure of the Corporation (including its Board of Directors,
independent legal counsel, or its stockholders) to make a determination prior to
the commencement of such action that indemnification of Indemnitee is proper in
the circumstances because Indemnitee has met the applicable standard of conduct
under applicable law, nor an actual determination by the Corporation (including
its Board of Directors, independent legal counsel or its stockholders) that
Indemnitee has not met such applicable standard of conduct, shall create a
presumption that Indemnitee has not met the applicable standard of conduct. The
court in which such action is brought shall determine whether Indemnitee or the
Corporation shall have the burden of proof concerning whether Indemnitee has or
has not met the applicable standard of conduct.

     5.  Advancement and Repayment of Expenses.  The Expenses incurred by
         -------------------------------------
Indemnitee in defending and investigating any Proceeding shall be paid by the
Corporation prior to the final disposition of such Proceeding within thirty days
after receiving from Indemnitee copies of invoices presented to Indemnitee for
such Expenses and an undertaking by or on behalf of Indemnitee to the
Corporation to repay such amount to the extent it is ultimately determined that
Indemnitee is not entitled to indemnification. In determining whether or not to
make an advance hereunder, the ability of Indemnitee to repay shall not be a
factor. Notwithstanding the foregoing, in a proceeding brought by the
Corporation directly, in its own right (as distinguished from an action brought
derivatively or by any receiver or trustee), the Corporation shall not be
required to make the advances called for hereby if a majority of the
disinterested directors determine that it does not appear that Indemnitee has
met the standards of conduct that made it permissible under applicable law to
indemnify Indemnitee and that the advancement of Expenses would not be in the
best interests of the Corporation and its stockholders.

     6.  Partial Indemnification. If Indemnitee is entitled under any provision
         -----------------------
of this Agreement to indemnification or advancement by the Corporation of some
or a portion of any Expenses or liabilities of any type whatsoever (including,
but not limited to, judgments, fines, penalties, and amounts paid in settlement)
incurred by him in the investigation, defense, settlement or appeal of a
Proceeding, but is not entitled to indemnification or advancement of the total
amount thereof, the Corporation shall nevertheless indemnify or pay advancements
to Indemnitee for the portion of such Expenses or liabilities to which
Indemnitee is entitled.

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     7.  Notice to Corporation by Indemnitee.  Indemnitee shall notify the
         -----------------------------------
Corporation in writing of any matter with respect to which Indemnitee intends to
seek indemnification hereunder as soon as reasonably practicable following the
receipt by Indemnitee of written notice thereof; provided that any delay in so
notifying the Corporation shall not constitute a waiver by Indemnitee of his
rights hereunder. The written notification to the Corporation shall be addressed
to the Board of Directors and shall include a description of the nature of the
Proceeding and the facts underlying the Proceeding and be accompanied by copies
of any documents filed with the court, if any, in which the Proceeding is
pending. In addition, Indemnitee shall give the Corporation such information and
cooperation as it may reasonably require and as shall be within Indemnitee's
power.

     8.  Defense of Claim.  In the event that the Corporation shall be obligated
         ----------------
under Section 5 hereof to pay the Expenses of any Proceeding against Indemnitee,
the Corporation, if appropriate, shall be entitled to assume the defense of such
Proceeding, with counsel approved by Indemnitee, which approval shall not be
unreasonably withheld, upon the delivery to Indemnitee of written notice of its
election to do so. After delivery of such notice, approval of such counsel by
Indemnitee and the retention of such counsel by the Corporation, the Corporation
will not be liable to Indemnitee under this Agreement for any fees of counsel
subsequently incurred by Indemnitee with respect to the same Proceeding;
provided that (i) Indemnitee shall have the right to employ his own counsel in
any such Proceeding at Indemnitee's expense, and (ii) if (A) the employment of
counsel by Indemnitee has been previously authorized by the Corporation, or (B)
Indemnitee shall have reasonably concluded that there may be a conflict of
interest between the Corporation and Indemnitee in the conduct of such defense
or (C) the Corporation shall not, in fact, have employed counsel to assume the
defense of such Proceeding, then the fees and expenses of Indemnitee's counsel
shall be paid by the Corporation.

     9.  Attorneys' Fees.  If any legal action is necessary to enforce the terms
         ---------------
of this Agreement, the prevailing party shall be entitled to recover, in
addition to other amounts to which the prevailing party may be entitled, actual
attorneys' fees and court costs as may be awarded by the court.

     10.  Continuation of Obligations. All agreements and obligations of the
          ---------------------------
Corporation contained herein shall continue during the period Indemnitee is a
director or officer of the Corporation, or is or was serving at the request of
the Corporation as a director, officer, fiduciary, employee or agent of another
corporation, partnership, joint venture, trust or other enterprise, and shall
continue thereafter so long as Indemnitee shall be subject to any possible
Proceeding by reason of the fact that Indemnitee served in any capacity referred
to herein.

     11.  Successors and Assigns.  This Agreement establishes contract rights
          ----------------------
that shall be binding upon, and shall inure to the benefit of, the successors,
assigns, heirs and legal representatives of the parties hereto.

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     12.  Non-exclusivity.
          ---------------

          (a) The provisions for indemnification and advancement of expenses set
forth in this Agreement shall not be deemed to be exclusive of any other rights
that Indemnitee may have under any provision of law, the Certificate or Bylaws,
the vote of the Corporation's stockholders or disinterested directors, other
agreements or otherwise, both as to action in his official capacity and action
in another capacity while occupying his position as a director or officer of the
Corporation.

          (b) In the event of any changes, after the date of this Agreement, in
any applicable law, statute, or rule that expand the right of a Delaware
corporation to indemnify its directors and officers, Indemnitee's rights and the
Corporation's obligations under this Agreement shall be expanded to the fullest
extent permitted by such changes. In the event of any changes in any applicable
law, statute or rule, that narrow the right of a Delaware corporation to
indemnify a director and officer, such changes, to the extent not otherwise
required by such law, statute or rule to be applied to this Agreement, shall
have no effect on this Agreement or the parties' rights and obligations
hereunder.

     13.  Effectiveness of Agreement. This Agreement shall be effective as of
          --------------------------
the date set forth on the first page and may apply to acts or omissions of
Indemnitee that occurred prior to such date if Indemnitee was a director or
officer of the Corporation or its predecessor, or was serving at the request of
the Corporation or its predecessor as a director, officer, employee or agent of
another corporation, partnership, joint venture, trust or other enterprise, at
the time such act or omission occurred.

     14.  Severability. Nothing in this Agreement is intended to require or
          ------------
shall be construed as requiring the Corporation to do or fail to do any act in
violation of applicable law. The Corporation's inability, pursuant to court
order, to perform its obligations under this Agreement shall not constitute a
breach of this Agreement. The provisions of this Agreement shall be severable as
provided in this Section 14. If this Agreement or any portion hereof shall be
invalidated on any ground by any court of competent jurisdiction, then the
Corporation shall nevertheless indemnify Indemnitee to the fullest extent
permitted by any applicable portion of this Agreement that shall not have been
invalidated, and the balance of this Agreement not so invalidated shall be
enforceable in accordance with its terms.

     15.  Governing Law.  This Agreement shall be interpreted and enforced in
          -------------
accordance with the laws of the State of Delaware without regard to its rules
pertaining to conflicts of laws. To the extent permitted by applicable law, the
parties hereby waive any provisions of law that render any provision of this
Agreement unenforceable in any respect.

     16.  Notice. All notices, requests, demands and other communications under
          ------
this Agreement shall be in writing and shall be deemed duly given (i) if
delivered by hand and receipted for by the party addressed, on the date of such
receipt, or (ii) if delivered by facsimile transmission to the recipient
followed by a copy sent by mail on the same date as the facsimile transmission,
on the date of receipt of such facsimile transmission, or (iii) if mailed by
certified or registered mail with postage prepaid, on the third business day
after the mailing date.

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Addresses for notice to either party are as shown on the signature page of this
Agreement, or as subsequently modified by written notice.

     17.  Mutual Acknowledgment. Both the Corporation and Indemnitee acknowledge
          ---------------------
that in certain instances, federal law or applicable public policy may prohibit
the Corporation from indemnifying its directors and officers under this
Agreement or otherwise. Indemnitee understands and acknowledges that the
Corporation has undertaken or may be required in the future to undertake with
the Securities and Exchange Commission to submit the question of indemnification
to a court in certain circumstances for a determination of the Corporation's
right under public policy to indemnify Indemnitee.

     18.  Counterparts. This Agreement may be executed in several counterparts,
          ------------
each of which shall constitute an original.

     19.  Amendment and Termination. No amendment, modification, termination or
          -------------------------
cancellation of this Agreement shall be effective unless in writing signed by
both parties hereto.

     IN WITNESS WHEREOF, the parties have executed this Agreement as of the day
and year set forth above.

                                    NEXELL THERAPEUTICS INC.,
                                    a Delaware corporation

                                    By:____________________________________

                                    Name:__________________________________

                                    Title:_________________________________

                                    Address: 9 Parker

                                             Irvine, CA  92618

                                    Tel:  (949) 470-6485
                                    Attn: William A. Albright, Jr.
INDEMNITEE:

__________________________
Name

__________________________
Position

Address:__________________

__________________________

Tel:______________________

Attn:_____________________

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