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                                                                   EXHIBIT 10.28

                    AMENDED AND RESTATED EMPLOYMENT AGREEMENT

         THIS AMENDED AND RESTATED EMPLOYMENT AGREEMENT (this "Agreement") is
dated as of December 15, 1998 by and between Alteon Inc., a Delaware corporation
(the "Company"), and Kenneth I. Moch (the "Employee").

         WHEREAS, the Company wishes to employ the Employee as Chief Executive
Officer and President of the Company; and

         WHEREAS, the Employee wishes to enter into the employ of the Company as
its Chief Executive Officer and President;

         NOW, THEREFORE, in consideration of the premises and the mutual
covenants contained herein, the parties hereby agree as follows;

         1. Term of Employment. Subject to the terms and conditions hereof, the
Company will employ the Employee, and the Employee will serve the Company, as
Chief Executive Officer and President for a period beginning on the date hereof
and terminating December 31, 2001, subject to extension by mutual agreement of
the Company and the Employee (such term, as it may be shortened by termination
of the Employee's employment hereunder pursuant to the provisions hereof or
extended, is hereinafter referred to as the "Term of Employment").

         2. Duties. (a) During the Term of Employment, the Employee will serve
as Chief Executive Officer and President, subject to the terms of this
Agreement, the direction and control of the Board of Directors of the Company,
and past practice with regard to authority, responsibility, and discretion in
the exercise of managerial prerogative. The primary location of the Employee's
employment hereunder shall be the headquarters of the Company. The Employee
will, during the Term of Employment, serve the Company faithfully, diligently
and competently and to the best of his ability, and will, consistent with the
dignity of Chief Executive Officer and President of the Company, hold, in
addition to the offices of Chief Executive Officer and President of the Company,
such other offices in the Company to which he may be appointed or assigned from
time to time by the Board of Directors of the Company and will discharge such
duties in connection therewith. The Employee shall devote all of his business
time to the performance of his duties hereunder, provided, that the Employee
shall not be precluded from serving as a member of up to two boards of directors
or advisory boards of companies or organizations so long as such service does
not violate the provisions of Section 9 of this Agreement or interfere with the
performance of the Employee's duties hereunder.

                  (b) During the Term of Employment, the Company will use its
best efforts to obtain the nomination of, and so long as the Employee is the
Chief Executive Officer of the Company, the election of the Employee as a
director of the Company. In the event that the

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Employee is elected as a director of the Company, the Employee shall perform all
duties incident to such directorship faithfully, diligently and competently.

         3. Compensation. The Company will, during the Term of Employment, pay
to the Employee as compensation for the performance of his duties and
obligations hereunder an initial base salary at the rate of $300,000 per annum
("Salary"), payable in equal semi-monthly installments. Such Salary shall be
reviewed annually by the Board of Directors of the Company in accordance with
the Company's compensation program solely for the purpose of determining
increases. In each of the Company's fiscal years during the Term of Employment,
the Employee shall be eligible to receive a bonus, to be awarded at the sole
discretion of the Board of Directors of the Company, in an amount of up to
$150,000. The Board shall use as a basis for determining the extent of such
bonus awards the attainment of stated goals and objectives for the Employee to
be set by the Compensation Committee of the Board after consultation with the
Employee. The Board of Directors shall advise the Employee in writing of the
goals and objectives for each fiscal year.

         4. Other Benefits.

                  (a) The Company shall grant to the Employee an incentive stock
option (or to the extent that such option does not qualify as an incentive stock
option, a non-qualified stock option), pursuant to the Company's 1987 or 1995
Stock Option Plan, to purchase 600,000 shares of Common Stock of the Company
("Common Stock") with an exercise price equal to the closing price of the
Company's Common Stock on the date of the grant of the option, which shall be
March 16, 1999. Such option shall be in the form of, and on such terms and
conditions as provided in, the Company's standard form of Stock Option Grant
Agreement in effect as of the date of this Agreement. Such Stock Option Grant
Agreement for such option shall provide, on condition that the Employee is
employed by the Company on the relevant vesting dates, that such options shall
vest as follows:

                           (1) 20,000 shares shall vest on the date of grant of
the option and 340,000 shares shall vest over a thirty-four month period at the
rate of 10,000 shares on the first day of each calendar month commencing on
March 1, 1999; and

                           (2) except as provided in subsection 4(d) of this
Agreement, 240,000 shares shall vest upon the accomplishment by the Employee of
four of eight milestones which shall be established by the Compensation
Committee of the Board after consultation with the Employee and set forth in the
Stock Option Grant Agreement. Such shares shall vest at the rate of 60,000
shares upon the accomplishment by the Employee of each of such four milestones.

                  (b) The Stock Option Grant Agreement shall contain provisions
to the effect that the options described in subsection 4(a)(2)of this Agreement
shall vest on the earlier of the time set forth in such subsection or the tenth
anniversary of the date of this Agreement, provided the Employee is then
employed by the Company.

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                  (c) As of the date of this Agreement and prior to the grant of
the stock options referred to in subsection 4(a) of this Agreement, the Employee
has stock options as set forth in Exhibit A. Pursuant to your Stock Option Grant
Agreement dated January 28, 1998, you have unvested options to purchase 40,000
shares of Common Stock, which options will vest upon the achievement of certain
milestones. That Stock Option Grant Agreement is hereby amended to provide that,
in lieu of the milestones provided therein, one-half (1/2) of such options shall
vest upon the achievement of the first of the milestones described in subsection
4(a)(2) of this Agreement and the balance shall vest upon the achievement of the
second such milestone.

                  (d) The Stock Option Grant Agreement shall contain provisions
to the following effect:

                           (1)  The options shall be transferable to the extent
afforded in the Company's 1987 or 1995 Stock Option Plan, as the case may be,
and as may be permissible under the applicable registration statement filed by
the Company under the Securities Act of 1933. The Company represents that it has
available or shall cause to be available sufficient shares under the Plan to
cover stock to be issued pursuant to such Plan upon the Employee's exercise of
the options.

                           (2) All unvested options will become exercisable
immediately upon a merger, consolidation, acquisition of property or stock,
reorganization (other than a mere reincorporation or the creation of a holding
company) or liquidation of the Company, as a result of which the shareholders of
the Company receive cash, stock or other property in exchange for or in
connection with their shares of the Company's Common Stock. In addition, such
options shall vest and become exercisable immediately in the event of a change
in control of the Company. A change in control of the Company shall be deemed to
occur if (a) the Company is merged with or into or consolidated with another
corporation or other entity under circumstances where the shareholders of the
Company immediately prior to such merger or consolidation do not own after such
merger or consolidation shares representing at least fifty percent of the voting
power of the Company or the surviving or resulting corporation or other entity,
as the case may be, or (b) if the Company is liquidated or sells or otherwise
disposes of substantially all of its assets to another corporation or entity, or
(c) if any person (as such term is used in Sections 13(d) and 14(d)(2) of the
Securities Exchange Act of 1934) shall become the beneficial owner (within the
meaning of Rule 13d-3 under such Act) of forty percent (40%) or more of the
Common Stock other than pursuant to a plan or arrangement entered into by such
person and the Company or otherwise approved by the Board of Directors, or (d)
during any period of two (2) consecutive years, individuals who at the beginning
of such period constitute the entire Board of Directors shall cease for any
reason to constitute a majority of the Board unless the election or nomination
for election by the Company's shareholders of each new director was approved by
a vote of at least two-thirds of the directors then still in office who were
directors at the beginning of the period.

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                           (3) In the event that the accelerated vesting caused
by Section 4(c)(2) of this Agreement (i) constitutes a "parachute payment"
within the meaning of Section 280G of the Internal Revenue Code, and (ii) but
for this Section 4(c)(3), would be subject to the excise tax imposed by Section
4999 of the Code (the "Excise Tax"), then the portion of the option which would
have become immediately vested and exercisable under Section 4(c)(2) may be
reduced to the portion which the Employee, in his sole discretion, determines
would result in no portion, or a lesser portion, of the option being subject to
the Excise Tax. The determination by the Employee of any reduction shall be
conclusive and binding upon the Company. The Company shall reduce the portion of
the option which is vested and exercisable only upon written notice by the
Employee indicating the amount of such reduction.

                  (e) The Employee shall be entitled during the Term of
Employment to participate in employee benefit plans and programs of the Company
to the extent that his position, tenure, salary, age, health and other
qualifications make him eligible to participate. The Company does not guarantee
the adoption or continuance of any particular employee benefit plan or program
during the Term of Employment, and the Employee's participation in any such plan
or program shall be subject to the provisions, rules, regulations and laws
applicable thereto; provided, however, that during the Term of Employment the
Employee shall be entitled to health, hospital, life and dental insurance
benefits consistent with the past practices of the Company in effect with
respect to Company personnel generally.

                  (f) During the Term of Employment, the Employee shall be
entitled to four (4) weeks vacation per year while employed hereunder. Such
vacation may be taken by the Employee at such times as do not unreasonably
interfere with the business of the Company. The accumulation of annual vacation
time earned but not taken will be in accordance with the Company policy
guidelines. Additional vacation will be earned in accordance with Company
policy.

         5. Expenses. During the Term of Employment, all travel and other
reasonable business expenses incident to the rendering of services by the
Employee under this Agreement will be paid or reimbursed by the Company subject
to the submission of appropriate vouchers and receipts in accordance with the
Company's policy from time to time in effect.

         6. Death or Disability.

                  (a) Employee's employment under this Agreement shall be
terminated by the death of the Employee. In addition, Employee's employment
under this Agreement may be terminated by the Board of Directors of the Company
if the Employee shall be rendered incapable by illness or any other disability
from complying with the terms, conditions and provisions on his part to be kept,
observed and performed for a period such that the Employee qualifies for
long-term disability benefits under any long-term disability policy the company
maintains which covers the Employee ("Disability"). If Employee's employment
under this Agreement is terminated by reason of Disability of the Employee,

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the Company shall give written notice to that effect to the Employee in the
manner provided herein. In the event that the Employee receives disability
insurance benefits paid for by the Company during any period prior to
termination of Employee's employment under this Agreement pursuant to this
Section 6(a), the Employee's Salary shall be reduced by an amount equal to such
disability insurance benefits during such period.

                  (b) In addition to and not in substitution for any other
benefits which may be payable by the Company in respect of the death or
Disability of the Employee, in the event of such death or Disability, the Salary
payable hereunder shall continue to be paid at the then current rate for three
(3) months after the termination of employment, and any bonus to which the
Employee would have been entitled for the year in which his death or Disability
occurs shall be pro rated to the date of his death or termination of employment
on account of Disability and paid not later than three (3) months after the
termination of employment. In the event of the death of the Employee during the
Term of this Agreement, the sums payable hereunder shall be paid to his personal
representative or executor.

         7. Disclosure of Information, Inventions and Discoveries. The Employee
shall promptly disclose to the Company all processes, trademarks, inventions,
improvements discoveries and other information related to the business of the
Company (collectively, "Developments") conceived, developed or acquired by him
alone or with others during the Term of Employment or during any earlier period
of employment by the Company or any predecessor of the Company, whether or not
during regular working hours or through the use of materials or facilities of
the Company. All such Developments shall be the sole and exclusive property of
the Company, and, upon request, the Employee shall promptly deliver to the
Company all drawings, sketches, models and other data and records relating to
such Developments. In the event any such Development shall be deemed by the
Company to be patentable, the Employee shall, at the expense of the Company,
assist the Company in obtaining a patent or patents thereon and execute all
documents and do all such other acts and things necessary or proper to obtain
letters of patents and to invest in the Company full right, title and interest
in and to such Developments.

         8. Non-Disclosure. The Employee shall not, at any time during or after
the Term of Employment or any earlier period of employment by the Company or any
predecessor of the Company, divulge, furnish or make accessible to anyone
(otherwise than in the regular course of business of the Company) or use for his
own account or for the account of any person any knowledge or information with
respect to confidential or secret processes, inventions, discoveries,
improvements, formulae, plans, materials, devices or ideas or other know-how,
whether patentable or not, with respect to any confidential or secret
development or research work or with respect to any other confidential or secret
aspects of the Company's business (including, without limitation, customer
lists, supplier lists and pricing arrangements with customers or suppliers).
This Section 8 shall not apply to any information which (i) is or becomes
generally available to the public other than as a result of a disclosure
directly or indirectly by the Employee or (ii) is or becomes available to the
Employee on a non-confidential basis from a person other than the Company or its
officers, directors or agents who to the Employee's knowledge after due inquiry
is not and

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was not bound by a confidentiality agreement with the Company and was not
otherwise prohibited from transmitting the information to the Employee.

         9. Non-Competition. The Company and the Employee agree that the
services rendered by the Employee hereunder are unique and irreplaceable. The
Employee hereby agrees that, during the Term of Employment and for a period of
one (1) year thereafter (the "Restricted Period"), the Employee shall not (i) in
any geographical area in the United States or in those foreign countries where
the Company, during the Term of Employment, conducts or proposes to conduct
business or initiates activities, engage or participate in, directly or
indirectly (whether as an officer, director, employee, partner, consultant,
holder of an equity or debt investment, lender or in any other manner or
capacity), or lend his name (or any part or variant thereof) to any business
which is, or as a result of the Employee's engagement or participation would
become, competitive with any aspect of the business of the Company, such
business being the commercialization of the measurement, prevention therapy or
reversal of glucose-mediated non-enzymatic cross-linking of macro-molecules, and
such other specific technologies in which the Company has, during the Term of
Employment or any earlier period of employment by the Company or any predecessor
of the Company, initiated significant plans to develop products, (ii) deal,
directly or indirectly, in a competitive manner with any customers doing
business with the Company during the Term of Employment or any earlier period of
employment by the Company or any predecessor of the Company (except in
connection with the performance of the duties and obligations of the Employee
during the Term of Employment), (iii) solicit any officer, director, employee,
consultant or agent of the Company to become an officer, director, employee,
consultant or agent of the Employee, his respective affiliates or anyone else if
such participation would be competitive with any aspect of the Company's
business; and (iv) engage in or participate in, directly or indirectly, any
business conducted under any name that shall be the same as or similar to the
name of the Company or any trade name used by it. Ownership, in the aggregate,
of less than 1% of the outstanding shares of capital stock of any corporation
with one or more classes of its capital stock listed on a national securities
exchange or publicly traded in the over-the-counter market shall not constitute
a violation of the foregoing provision.

         10. Remedies. The Employee acknowledges that irreparable damage would
result to the Company if the provisions of Section 7, 8, 9 or 14 were not
specifically enforced, and agrees that the Company shall be entitled to any
appropriate legal, equitable or other remedy, including injunctive relief, in
respect to any failure to comply with the provisions of Section 7, 8, 9 or 14.

         11. Termination for Cause. In addition to any other remedy available to
the Company, either at law or in equity, the Employee's employment with the
Company may be terminated by the Board of Directors for cause, which shall
include (i) the Employee's conviction from which no further appeal may be taken
for, or plea of nolo contendere to, a felony or a crime involving moral
turpitude, (ii) the Employee's commission of a breach of fiduciary duty
involving personal profit in connection with the Employee's employment by the
Company, (iii) the Employee's commission of an act which the Board of Directors
shall

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reasonably have found to have involved willful misconduct or gross negligence on
the part of the Employee, in the conduct of his duties under this Agreement,
(iv) habitual absenteeism, or (v) the Employee's material breach of any material
provision of this Agreement which remains uncured for a period of thirty (30)
days following notice by the Company. With respect to the matters set forth in
subsections (iii), (iv) and (v) hereof, the Company may not terminate the
Employee's employment unless the Employee has first been given notice of the
conduct forming the cause for such termination and an opportunity to explain
such conduct to the Board of Directors or a committee thereof. In the event of
termination under this Section 11, the Company's obligations under this
Agreement shall cease and the Employee shall forfeit all rights to receive any
future compensation under this Agreement. Notwithstanding any termination of
this Agreement pursuant to this Section 11, the Employee, in consideration of
his employment hereunder to the date of such termination, shall remain bound by
the provisions of Section 7, 8, 9 and 14 hereof.

         12. Termination Without Cause. Each of the Company and Employee may
terminate Employee's employment under this Agreement at any time for any reasons
whatsoever, without any further liability or obligation of the Company to the
Employee or of the Employee to the Company from and after the date of such
termination (other than liabilities or obligations accrued but unsatisfied on,
or surviving, the date of such termination), by sending thirty (30) days prior
written notice to the other party. Such notice shall state the effective date of
termination of Employee's employment under this Agreement.

 In the event (a) the Company elects to terminate Employee's employment under
this Agreement or (b) the Company gives Employee notice of its election not to
extend the Term of Employment beyond the expiration of the then current Term of
Employment, or (c) by the date which is four (4) months prior to the end of the
then current Term of Employment, the Company has not offered to extend the then
current Term of Employment on terms and conditions at least as favorable to
Employee as those in effect during the then current Term of Employment or (d)
the Employee terminates his employment under this Agreement following a
Detrimental Change (as defined below), then

                  (a) the Company shall pay to the Employee an amount equal to
his then current annual Salary (exclusive of bonuses) in equal installments over
a twelve month period commencing on the effective date of the termination of the
Employee's employment under this agreement in accordance with the Company's
normal payroll practices.

                  (b) the Company will enter into a consulting agreement with
the Employee pursuant to which it will retain the Employee to provide such
consulting services as the Company shall request for a period of twelve (12)
months following the expiration of the Term of Employment for an annual
consulting fee equal to one-half of the Employee's annual salary (exclusive of
bonuses) at the time of termination of his employment under this Agreement;

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                  (c) for a period of eighteen (18) months following the
effective date of termination of the Employee's employment under this Agreement,
so long as reasonably comparable coverage is not provided to him by another
person or entity with which he has commenced employment, the Company will
provide him with all health, dental and hospital insurance benefits to which he
is entitled under the federal law popularly known as COBRA without cost; and

                  (d) the Company will amend the terms of all stock option grant
agreements then in effect between the Employee and the Company to provide that
all options which are vested on the effective date of the termination of the
Employee's employment under this Agreement shall be exercisable until the
earlier of (i) the expiration date set forth in the stock option grant agreement
(without regard to the effect of the termination of the Employee's employment on
the term of the option) or (ii) the second anniversary of the effective date of
the termination of the Employee's employment under this Agreement. The Employee
acknowledges that under applicable law any vested options exercised more than
three (3) months after he ceases to be employed by the Company shall not be
eligible for federal income tax treatment as incentive stock options and shall
be non-qualified stock options.

In the event the Employee elects to terminate prior to the end of the Term of
Employment (other than as a result of a Detrimental Change), the Company's
obligation to pay Salary shall cease as of the effective date of termination.
Notwithstanding any termination of this Agreement pursuant to this Section 12,
the Employee, in consideration of his employment hereunder to the date of such
termination, shall remain bound by the provisions of Section 7, 8, 9 and 14
hereof. Any termination of this Agreement by the Company as provided in this
Section 12 shall be in addition to, and not in substitution for, any rights with
respect to termination of the Employee which the Company may have pursuant to
Section 11. As used in this Agreement, Detrimental Change shall mean the failure
of the Company to comply with the terms of this Agreement, a material reduction
in the Employee's duties or responsibilities hereunder or the relocation of the
Employee's primary office of employment to a location more than thirty-five (35)
miles from the location of such office prior to the relocation or substantially
increased travel requirements.

         13. Resignation. In the event that the Employee's services under this
Agreement are terminated under any of the provisions of this Agreement (except
by death), the Employee agrees that he will deliver his written resignation from
all positions held with the Company to the Board of Directors, such resignation
to become effective immediately; provided, however, that nothing herein shall be
deemed to affect the provisions of Section 7, 8, 9, 12, 14 and 15 hereof
relating to the survival thereof following termination of the Employee's
services hereunder, and provided, further, that except as expressly provided in
this Agreement, the Employee shall be entitled to no further compensation
hereunder.

         14. Data. Upon termination of the Term of Employment or termination
pursuant to Sections 6, 11 or 12 hereof, the Employee or his personal
representative shall promptly

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deliver to the Company all books, memoranda, plans, records and written data of
every kind relating to the business and affairs of the Company which are then in
his possession.

         15. Insurance. The Company shall have the right, at its own cost and
expense to apply for and to secure in its own name, or otherwise, life, health
or accident insurance or any or all of them covering the Employee, and the
Employee agrees to submit to usual and customary medical examinations and
otherwise to cooperate with the Company in connection with the procurement of
any such insurance, and any claims thereunder. The Company will use its best
reasonable efforts to maintain directors' and officers' liability insurance with
coverage comparable to that in place on the date of this Agreement during the
term of your service as an officer or director of the Company and thereafter for
as long as you may have any liability which would be covered by such insurance.
The requirements of the preceding sentence shall survive termination of your
employment under this Agreement.

         16. Waiver of Breach. Any waiver of any breach of this Agreement shall
not be construed to be a continuing waiver or consent to any subsequent breach
on the part either of the Employee or of the Company.

         17. Assignment. This Agreement shall inure to the benefit of and be
binding upon the successors and assigns of the Company upon any sale of all or
substantially all of the Company's assets, or upon any merger or consolidation
of the Company with or into any other entity, all as though such successors and
assigns of the Company and their respective successors and assigns were the
Company. Insofar as the Employee is concerned, this Agreement, being personal,
may not be assigned.

         18. Severability. To the extent any provision of this Agreement shall
be invalid or unenforceable, it shall be considered deleted therefrom and the
remainder of such provision and of this Agreement shall be unaffected and shall
continue in full force and effect. In furtherance and not in limitation of the
foregoing, should the duration or geographical extent of, or business activities
covered by, any provision of this Agreement be in excess of that which is valid
and enforceable under applicable law, then such provision shall be construed to
cover only that duration, extent or activities which may be validly and
enforceable covered.

         19. Notices. All notices, requests and other communications pursuant to
this Agreement shall be in writing and shall be deemed to have been duly given,
if delivered in person or by courier, telegraphed, telexed or by facsimile
transmission or five business days after being sent by registered or certified
mail, return receipt requested, postage paid, addressed as follows:

                  If to the Employee:

                           Kenneth I. Moch
                           68 Willow Avenue

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                           Larchmont, NY 10538

                           with a copy to:

                           Herbert Eisenberg, Esq.
                           Davis & Eisenberg
                           377 Broadway
                           New York, NY 10013

                  If to the Company:

                           Alteon Inc.
                           170 Williams Drive
                           Ramsey, NJ 07446

                           with a copy to:

                           Richard J. Pinto, Esq.
                           Smith, Stratton, Wise, Heher & Brennan
                           600 College Road East
                           Princeton, NJ  08540

Any party may, by written notice to the other in accordance with this Section
19, change the address to which notices to such party are to be delivered or
mailed.

         20. General. Except as otherwise provided herein, the terms and
provisions of this Agreement, all stock options grant agreements currently in
effect between the Employee and the Company as set forth on Exhibit A and the
Stock Option Grant Agreement to be entered into between the Company and the
Employee as provided above shall constitute the entire agreement by the Company
and the Employee with respect to the subject matter hereof, and shall supersede
any and all prior agreements or understandings between the Employee and the
Company, whether written or oral. This Agreement shall be construed and enforced
in accordance with the laws of the State of New Jersey. This Agreement may be
amended or modified only by a written instrument executed by the Employee and
the Company. This Agreement may be executed in any number of counterparts, all
of which, when executed, shall be deemed to be an original, and all of which
together shall constitute one and the same instrument.

         IN WITNESS WHEREOF, the parties have executed this Employment Agreement
as of the day and year first above written.

                                           Alteon Inc.

                                           /s/ Mark Novitch
                                           -----------------------------------
                                           By:

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                                           Title:   Chairman

                                           /s/ Kenneth I. Moch
                                           -----------------------------------
                                           Kenneth I. Moch

                                      -11-<PAGE>   1
                                                                   Exhibit 10.13

                        AMENDMENT TO AMENDED AND RESTATED
                                CREDIT AGREEMENT

                  THIS AMENDMENT TO AMENDED AND RESTATED CREDIT AGREEMENT (this
"Amendment"), dated as of March 29, 1999 by and among Safeguard Scientifics,
Inc., a Pennsylvania corporation ("SSI" or a "Borrower"), Safeguard Scientifics
(Delaware) Inc., a Delaware corporation ("SSD" or a "Borrower"), Safeguard
Delaware, Inc., a Delaware corporation ("SDI" or a "Borrower" and, collectively
with SSI and SSD, the "Borrowers") and PNC Bank, National Association ("PNC", as
agent for the "Lenders" under the Loan Agreement (in such capacity, "Agent")).

                                   BACKGROUND

                  A. The parties, together with the other Lenders identified
therein, entered into that certain Amended and Restated Credit Agreement dated
April 17, 1998 (as amended to date, the "Loan Agreement").

                  B. Lenders, through the Agent, and the Borrowers desire to
amend the Loan Agreement in the manner hereinafter set forth.

                  C. Capitalized terms that are not defined herein shall have
the meanings ascribed to them in the Loan Agreement.

                  D. Subject to compliance with all conditions specified herein,
all amendments hereinafter set forth are effective as of the date hereof unless
otherwise expressly stated herein to the contrary.

                  NOW, THEREFORE, intending to be legally bound, the parties
agree as follows:

                  1. RELEASE OF LIEN. SSI and SSD are, on the date hereof,
entering into a certain contract (the "Credit Suisse Contract") with Credit
Suisse Financial Products ("Credit Suisse") pursuant to which SSI and SSD have
agreed to deliver to Credit Suisse one million (1,000,000) shares of Tellabs
Inc. (f/k/a Coherent Communications Systems Corporation) common stock. Agent
hereby releases any and all liens on, and pledges of, the stock to be delivered
pursuant to the Credit Suisse Contract, consisting of one million (1,000,000)
shares of Tellabs Inc. common stock (hereinafter, the "Released Stock"),
together with all proceeds thereof and all cash and noncash dividends and other
distributions with respect thereto. Agent further agrees to hereafter release
such additional shares of Tellabs Inc. common stock that pursuant to the Credit
Suisse Contract are to be hereafter delivered by SSI and SSD to Credit Suisse,
together with the proceeds thereof and all cash and noncash dividends and other
distributions with respect thereto. All proceeds received by SSI and SSD from
Credit Suisse on account of such delivery shall be applied by SSI and SSD
against the principal balance of the Loans. Accordingly, the Released Stock
shall no longer constitute either "Pledged Securities" or "Collateral Coverage
Securities" for any purpose of the Credit Agreement. However, should, pursuant
to the Credit Suisse Contract, SSI and/or SSD receive from or retain the
Released Stock free of the rights of

<PAGE>   2

Credit Suisse, the same shall be pledged to the Lenders pursuant to the Amended
and Restated Pledge Agreement between the Borrowers and Agent, dated April 17,
1998.

                  2. WAIVER OF VIOLATIONS. Agent hereby waives any and all
violations of the following provisions of the Loan Agreement by reason of the
Credit Suisse Contract and the transactions effected thereby:

                  A. Section 6.3, "Indebtedness," to the extent it would
prohibit the incurrence of SSI's and/or SSD's obligations to Credit Suisse;

                  B. Section 6.4, "Liens," to the extent it would prohibit the
granting by SSI and/or SSD of a security interest in or other rights to the
Released Stock;

                  C. Section 6.11, "Sale of Assets," to the extent it would
prohibit the disposition of the Released Stock.

                  3. MISCELLANEOUS.

                  A. Construction. The provisions of this Amendment shall be in
addition to those of the Loan Agreement, the Notes and the Security Documents,
all of which shall be construed as integrated and complementary to each other.
In the event of any express inconsistency between the terms hereof and those
contained in the Loan Agreement, the terms hereof shall control. Except as
modified by the terms hereof, all terms and provisions of the Loan Agreement
remain unchanged and in full force and effect.

                  B. Binding Effect; Assignment and Entire Agreement. This
Amendment shall inure to the benefit of, and shall be binding upon, the
respective successors and permitted assigns of the parties hereto. Borrowers
have no right to assign any of their rights or delegate any of their obligations
hereunder without the prior written consent of Lenders. This Amendment, together
with the Loan Agreement, the Notes and the Security Documents, constitute the
entire agreement among the parties relating to the subject matter thereof. All
exhibits referred to herein and attached hereto shall be deemed expressly
incorporated herein by reference and made a part hereof.

                  C. Waiver of Jury Trial. BORROWERS AND LENDERS IRREVOCABLY
WAIVE TRIAL BY JURY AND THE RIGHT THERETO IN ANY LITIGATION IN ANY COURT WITH
RESPECT TO, IN CONNECTION WITH, OR ARISING OUT OF, THIS AMENDMENT, THE NOTES,
SECURITY DOCUMENTS, OR ANY INSTRUMENT OR DOCUMENT DELIVERED PURSUANT TO THIS
AMENDMENT, OR THE VALIDITY, PROTECTION, INTERPRETATION, COLLECTION OR
ENFORCEMENT THEREOF.

                  D. Expenses. In addition to all other expense reimbursement
obligations of the Borrowers contained in the Loan Agreement and the Security
Documents, Borrowers will reimburse Lenders for all costs and expenses,
including reasonable attorneys' fees, incurred by Lenders in the negotiation,
preparation and consummation of this Amendment and the documents to be delivered
pursuant hereto.

                                       -2-
<PAGE>   3

                  E. Reaffirmation and Release. Borrowers ratify and reaffirm
all of their Obligations to Lenders and agree that the same are owing without
set-off, counterclaim or other defense of any nature. Borrowers specifically
ratify and reaffirm all waiver of jury trial provisions set forth in the Loan
Agreement, the Notes and the Security Documents.

                  IN WITNESS WHEREOF, the parties hereto have caused this
Amendment to be executed and delivered by their duly authorized officers as of
the day and year first above written.

                                    LENDERS:

                                    PNC BANK, NATIONAL ASSOCIATION, AS AGENT

                                    By: /s/ Joseph G. Meterchick
                                       ----------------------------------------
                                       Name: Joseph G. Meterchick
                                       Title: Vice President

                                   BORROWERS:

                                    SAFEGUARD SCIENTIFICS, INC.

                                    By: /s/ Michael W. Miles
                                       ----------------------------------------
                                       Name: Michael W. Miles
                                       Title: Senior Vice President & CFO

                                    SAFEGUARD SCIENTIFICS (DELAWARE) INC.

                                    By: /s/ Michael W. Miles
                                       ----------------------------------------
                                       Name: Michael W. Miles
                                       Title: Senior Vice President & CFO

                                    SAFEGUARD DELAWARE, INC.

                                    By: /s/ Michael W. Miles
                                       ----------------------------------------
                                       Name: Michael W. Miles
                                       Title: Senior Vice President & CFO

                                       -3-

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