Document:

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                                                                  EXHIBIT 10.14

                                  GENVEC, INC.

                             CONSULTING AGREEMENT

     THIS CONSULTING AGREEMENT (the "Agreement"), effective as of March 17, 1999
(the "Effective Date"), is entered into between Herbert J. Conrad, residing at
134 Lowell Road, Glen Rock, New Jersey 07452 ("Consultant"), and GenVec,
Inc., a Delaware corporation having a principal place of business at 12111
Parklawn Drive, Rockville, MD 20852 ("GenVec").

                                  BACKGROUND

     A. Consultant currently is serving as the Chairman of the Board of
Directors of GenVec.

     B. GenVec desires to retain the services of Consultant in a consulting
capacity with respect to certain activities as described in this agreement.

     NOW, THEREFORE, Consultant and GenVec agree as follows:

     1.   DESCRIPTION OF SERVICES. GenVec hereby retains Consultant and
Consultant hereby agrees to consult regarding GenVec's activities. Such
consulting services may take place between GenVec's management, scientists,
or other consultants, in the form of formal meetings, review of written
materials, informal consultation over the telephone, or otherwise, as agreed
by the parties.

     2.   COMPENSATION. As consideration for Consultant's performance of the
Agreement, GenVec shall pay Consultant One Thousand Five Hundred U.S. Dollars
($1,500.00) per day of consulting service requested by GenVec, and rendered
by Consultant. For purposes of this Agreement, eight (8) hours shall
constitute one day of consulting service. Consultant agrees to make himself
available to GenVec to provide consulting services for a minimum of five (5)
business days and up to ten (10) business days per month. Consulting services
rendered for any portion of one day hereunder shall be compensated on an
hourly basis at the rate of One Hundred Eighty-Seven U.S. Dollars ($187.00)
per hour. GenVec shall pay such consideration within thirty (30) days of
Consultant's rendering of such services. In the event that Consultant renders
more than 10 days of consulting service, Consultant shall provide to GenVec
written documentation, in a form reasonably acceptable to GenVec, stating the
number of additional days (or hours, if applicable) of consulting services
provided during the prior calendar month. Such statement shall be sent to the
attention of the Accounts Payable Department at GenVec, and GenVec shall pay
such consideration within thirty (30) days of receiving such documentation.
Consultant acknowledges that no amount will be withheld from his consulting
fees hereunder for payment of any federal, national, state, or local taxes,
and that Consultant has sole responsibility to pay such taxes, if any, and to
file such returns as may be required by applicable laws and regulations.

     3.   EXPENSES. GenVec will reimburse Consultant for reasonable,
documented expenses incurred by Consultant while rendering services under
this Agreement, subject to approval and

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customary verification by GenVec. Such expenses shall include reasonable
necessary travel, lodging, and meal expenses. Requests for reimbursement
shall be in a reasonable form acceptable to GenVec and shall include an
itemized accounting of such expenses supported by documentation.

     4.   PROPRIETARY INFORMATION AND INVENTIONS.

          4.1  PROPRIETARY INFORMATION. Consultant acknowledges that his
relationship with GenVec is one of high trust and confidence and that in the
course of his service to GenVec he will have access to and contact with
Proprietary Information. The Consultant agrees that he will not, during the
Term (as defined in Section 7 below) of the Agreement or at any time within
five (5) years thereafter, disclose to others, or use for his benefit or the
benefit of others, any Proprietary Information or Inventions (as defined in
Section 4.3 below).

               4.1.1  For purposes of this Agreement, "Proprietary
Information" shall mean all information (whether or not patentable and
whether or not copyrightable) owned, possessed or used by GenVec, including,
without limitation, any Invention, formula, trade secret, process, research,
report, technical data, know-how, technology or information with respect to
employee compensation, or any marketing plan or business plan, or forecasts,
customer lists or information regarding finances, marketing, pricing, or
costs that is communicated to, learned of, developed or otherwise acquired by
Consultant as a direct result of the services performed by Consultant for
GenVec under the Agreement.

               4.1.2  Consultant's obligations under this Section 4.1 shall
not apply to any information that (i) is or becomes known to the general
public under circumstances involving no breach by the Consultant or others of
the terms of this Section 4.1, or (ii) is in Consultant's possession at the
time of disclosure, as shown by contemporaneous written evidence.

          4.2  OWNERSHIP AND RETURN OF PROPERTY. All documents, data,
records, apparatus, equipment and other physical property, whether or not
pertaining to Proprietary Information, furnished to Consultant by GenVec or
produced by Consultant or others in connection with Consultant's services
shall be and remain the sole property of GenVec and shall be returned
promptly to GenVec as and when requested by GenVec. Should GenVec not so
request, Consultant shall promptly return and deliver all such materials and
property upon termination of this Agreement for any reason, and Consultant
will not retain any such property or any reproduction or extract thereof
following any termination.

          4.3  INVENTIONS.

               4.3.1  OWNERSHIP. All inventions, discoveries, data,
technology, designs, innovations, and improvements related to the business of
GenVec which are made, conceived reduced to practice or otherwise developed
by the Consultant, solely or jointly with others, as a direct result of
services performed under the terms of this Agreement (collectively,
"Inventions") or GenVec's Proprietary Information received by the Consultant
under the terms of this Agreement shall be the property of GenVec. Consultant
hereby assigns to GenVec any right, title and interest he may have in any and
all Inventions and any and all related patents, copyrights, trademarks, trade
names,

                                      -2-
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and other industrial and intellectual property rights and applications
therefor, in the United States and elsewhere, and appoints the Chief
Executive Officer of GenVec as his duly authorized attorney to execute, file,
prosecute and protect the same before any government agency, court or
authority.

               4.3.2  DISCLOSURE. During the term of this Agreement and
within one (1) year thereafter, Consultant will promptly disclose to GenVec
all Inventions.

               4.3.3  COOPERATION. Upon the request of GenVec and at GenVec's
expense, Consultant shall execute such further assignments, documents and
other instruments as may be necessary or desirable to fully and completely
assign all Inventions to GenVec and to assist GenVec in applying for,
obtaining, defending and enforcing patents and/or copyrights or other rights
in the United States and in any foreign country with respect to any
Inventions.

          4.4  RELEVANT DEVELOPMENTS. In the event that Consultant invents or
discovers, or participates in the invention or discovery, of technology or
information relevant to the business of GenVec, Consultant agrees to use his
best efforts to notify GenVec of such invention or discovery and to assist
GenVec with the possible purchase or licensing of such invention or discovery.

     5.   OTHER CONSULTANT OBLIGATIONS.

          5.1  Consultant will not disclose to GenVec any information that
Consultant is obligated to keep secret pursuant to an existing agreement with
a third party or consistent with his duties or obligations to such third
party and nothing in this Agreement win impose any obligation on Consultant
to the contrary.

          5.2  The consulting services provided by Consultant hereunder will
not be conducted on time that is required to be devoted to any third party.
Consultant shall not use the funding, resources or facilities of any other
third party to perform consulting services hereunder and shall not perform
such services in any manner that would give any third party rights to any
result of such services.

          5.3  Subject to written waivers that may be provided by GenVec upon
Consultant's request, which waivers shall not be unreasonably withheld,
Consultant agrees that during the term of this Agreement he will not directly
or indirectly (i) provide any consulting services in the field of gene
therapy to any other business or commercial entity, (ii) participate in the
formation of any business or commercial entity in the field of gene therapy,
or (iii) solicit or hire away, or assist a third party to solicit or hire
away, any employee or consultant of GenVec. Consultant shall promptly notify
GenVec of all other consulting agreements which Consultant has entered into,
or any consulting services which Consultant may provide to any third party
relating to gene therapy.

     6.   NATURE OF RELATIONSHIP. At all times while acting pursuant to this
Agreement, Consultant shall be deemed an independent contractor and will not
be deemed to be an employee of GenVec for any purpose, including without
limitation, for the purpose of any employee benefit program, tax withholding,
unemployment benefits, or otherwise. Consultant acknowledges and agrees and
it is the intent of the parties hereto that Consultant receive no
GenVec-sponsored benefits

                                      -3-

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from GenVec either as Consultant or employee. Such benefits include, but are
not limited to, paid vacation, sick leave, medical insurance, and 401(k)
participation. If Consultant is reclassified by a state or federal agency or
court as an employee, Consultant will become a reclassified employee and will
recieve no benefits except those mandated by state or federal law, even if by
the terms of GenVec's benefits plans in effect at the time of such
reclassification Consultant would otherwise be eligible for such benefits.
Consultant shall not enter into any agreement or incur any obligations on
GenVec's behalf, or commit GenVec in any manner. Consultant further agrees to
indemnify and hold harmless GenVec and its directors, officers, and
employees from and against all taxes, losses, damages, liabilities, costs and
expenses, including attorney's fees and other legal expenses, arising
directly or indirectly from (i) any negligent reckless or intentionally
wrongful act of Consultant or Consultant's assistants, employees or agents,
(ii) a determination by a court or agency that the Consultant is not an
independent contractor, or (iii) any breach by Consultant or Consultant's
assistants, employees or agents of any convenants contained in this Agreement.

     7.    TERM.  This Agreement shall become effective as of the Effective
Date and remain in effect until the first anniversary of the Effective Date,
unless terminated earlier pursuant to Section 8 (the "Term"), and, if
mutually agreed, may be extended on a month to month basis, on the same terms
and conditions herein.

     8.    TERMINATION.  Each of GenVec and Consultant may terminate this
Agreement for any reason upon thirty (30) days written notice to the other
party. This Agreement shall automatically terminate upon death of Consultant.
Termination or expiration of this Agreement or any mutually agreed extension
shall not relieve a party with respect to any obligation accrued hereunder
prior to such expiration or termination. Section 4, 5 and 9 through 13 shall
survive any expiration or termination of this Agreement.

     9.    REMEDIES.  Consultant acknowledges that GenVec will suffer
irreparable harm and have no adequate remedy at law if Consultant violates
the terms of Section 4 or 5. In such event, Gen Vec shall have the right, in
addition to any other rights it may have, to obtain in any court of
competent jurisdiction injunctive or other relief to restrain any breach or
threaten breach of this Agreement without the obligation of posting any bond.

     10.   GOVERNING LAW.  This Agreement shall be governed and construed in
accordance with the laws of the State of Maryland, U.S.A., and the exclusive
venue for any dispute between the parties regarding the subject manner of
this Agreement shall be the state and federal courts located in the State of
Maryland, U.S.A., and the parties hereby consent to the personal jurisdiction
of such courts.

     11.   NO CONFLICT.  Consultant represents that his retention as a
consultant with Gen Vec and his performance under this Agreement does not,
and shall not, breach any agreement that obligates him to keep in confidence
any trade secrets or confidential or proprietary information of his or of any
other party or to refrain from competing, directly or indirectly, with the
business of any other party. Consultant shall not disclose to GenVec any
trade secrets or confidential or proprietary information of any other party.

                                      -4-
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     12.   ASSIGNMENT.  GenVec shall have the right to assign its rights
under this Agreement to any person, partnership, corporation, or other
entity, provided that any assignee, transferee, or other successor agrees to
be bound by the terms hereof. Consultant shall not assign this Agreement
without Gen Vec's prior written consent. This Agreement shall be binding on
Gen Vec, its successors and assigns, and on Consultant, his heirs and assigns.

     13.   NOTICES.  Any notice required or permitted hereunder shall be in
writing and considered given when personally delivered or sent by certified
or registered mail, postage paid, or overnight delivery service, if to
Consultant, at his residence listed above, and if to Gen Vec, at the address
listed above, attention: President.

     14.   ENTIRE AGREEMENT; COUNTERPARTS.  This Agreement constitutes the
entire agreement between the parties and supersedes all prior written and
oral agreements between the parties with respect to Mr. Conrad's consulting
arrangement with the Company, any payment therefor and all other subject
matters herein. Mr. Conrad acknowledges and agrees that he has received all
payments (including cash and equity) owed to him by the Company as of the
date of this Agreement, other than options granted to him effective as of the
date of this Agreement. No change, amendment, or other modification of this
Agreement shall be effective unless signed by Consultant and an authorized
representative of GenVec. This Agreement may be executed in counterparts,
each of which shall be deemed an original and all of which shall constitute
one instrument.

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

GENVEC,INC.CONSULTANT

By:_________________________________     By:____________________________________
       Paul H. Fischer                          Herbert J. Conrad
Title: President and Chief Executive
         Officer

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[LOGO]                                                 65 West Watkins Mill Road
                                                       Gaithersburg, MD 20878
                                                       ph: 240-632-0740
                                                       fx: 240-632-0735
                                                       www.genvec.com

March 1, 2000

VIA FEDERAL EXPRESS

Herb J. Conrad
134 Lowell Road
Glen Rock, NJ 07452

     RE: CONSULTING AGREEMENT WITH HERB J. CONRAD (GV REF. NO. CSA6O04)

Dear Herb:

     This letter will confirm the extension of the Consulting Agreement
entered into between you ("Consultant") and GenVec, Inc. ("Gen Vec")
effective March 17, 1999 (the "Agreement"). Pursuant to Section 7 of the
Agreement, the parties hereby agree that the term of the Agreement shall be
extended an additional year on the same terms and conditions of the
Agreement, such that it shall terminate on March 17, 2001 ("Term"). In
consideration of the extension of the Agreement for an additional year,
Gen Vec shall pay Consultant fifteen hundred U.S. dollars ($1,500.00) per day
of consulting services requested by Gen Vec and rendered by Consultant.

     Please indicate agreement to the above by countersigning this letter and
returning one copy to my attention. Please do not hesitate to contact me if
you have any questions.

Yours truly,

/s/ Paul H. Fischer
-------------------------------------
Paul H. Fischer
President and Chief Executive Officer

UNDERSTOOD AND AGREED:

Herb J. Conrad

By:    /s/ Herb J. Conrad
   ----------------------------------
           Herb J. Conrad

Date: 3/1/00<PAGE>
                                                                 EXHIBIT 10.15

                                  GENVEC, INC.

                              AMENDED AND RESTATED

                          REGISTRATION RIGHTS AGREEMENT

         THIS AMENDED AND RESTATED REGISTRATION RIGHTS AGREEMENT (the
"Agreement") is made as of December 2, 1998 by and among GenVec, Inc., a
Delaware corporation (the "Company") and the purchasers of the Company's Class
F Convertible Preferred Stock, set forth on SCHEDULE 7 (the "Class F
Purchasers"), the stockholders set forth on SCHEDULE 1 (the "Class A and B
Purchasers"), the stockholders set forth on SCHEDULE 2 (the "Additional Class
B Purchasers"), the stockholders set forth on SCHEDULE 3 (the "Theragen Common
Purchasers"), the stockholders set forth on SCHEDULE 4 (the "Theragen
Preferred Purchasers"), and together with the Theragen Common Purchasers, the
"Theragen Purchasers"), the stockholders set forth on SCHEDULE 5 (the "Class C
Purchasers"), the stockholders set forth on SCHEDULE 6 (the "Second Class C
Purchasers"), SCIOS, Inc. ("SCIOS"), the Warner-Lambert Company
("Warner-Lambert"), and Ronald G. Crystal, M.D. ("Crystal") (collectively,
excluding the Class F Purchasers, referred to as the "Original Investors").

                                   BACKGROUND

         A. The Company and the Class F Purchasers are parties to the Class F
Convertible Preferred Stock and Warrant Purchase Agreement (the "Class F
Agreement") pursuant to which the Company proposes to sell and issue up to
1,000,000 shares of Class F Preferred Stock and warrants to purchase up to
250,000 shares of Common Stock.

         B. The Company and the Original Investors are parties to the
Registration Rights Agreement, dated as of April 22, 1998 (the "Original
Agreement"), pursuant to which the Original Investors have certain rights,
including but not limited to registration rights.

         C. The Company desires to provide a further inducement to the Class F
Purchasers to purchase shares of its Class F Preferred Stock by providing the
rights set forth herein.

         D. The Company has requested and the requisite majority of the
Registrable Securities (as such term is defined in the Original Agreement)
have agreed, pursuant to Section 3.3 of the Original Agreement, to amend and
restate in its entirety the Original Agreement, in the manner set forth
herein, and hereby agree that this New Agreement shall govern the rights of
the Original Investors and the Class F Purchasers to cause the Company to
register shares of the Common Stock issuable to the Original Investors and to
the Class F Purchasers and certain other matters set forth herein.

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         NOW THEREFORE, the parties hereby amend and restate the Original
Agreement in its entirety as follows:

                                    SECTION 1

                                  TERMINATIONS

         1.1 CLASS A AND B AGREEMENT. In consideration for the rights granted
in this Agreement, the Class A and B Purchasers agree that Section 4.2 and
Section 8 of the Amended and Restated Preferred Stock Purchase Agreement,
dated as of May 19, 1993, as amended by Amendment #1, dated as of November 17,
1994 and as further amended by the Amendment and Waiver Agreement, dated as of
September 19, 1995 and Amendment #1, dated as of October 3, 1997 (the "Class A
and B Agreement") (including all rights and obligations under such sections)
are terminated and of no further force and effect. All other sections and
portions of the Class A and B Agreement, and all other rights granted to, and
all obligations of, the parties under the Class A and B Agreement shall remain
in full force and effect.

         1.2 CLASS B AGREEMENT. In consideration for the rights granted in
this Agreement, the Additional Class B Purchasers agree that Section 4.2 and
Section 8 of the Preferred Stock Purchase Agreement, dated as of May 26, 1993,
as amended by Amendment #1, dated as of November 17, 1994 and as further
amended by the Amendment and Waiver Agreement, dated as of September 19, 1995
and Amendment #1, dated October 3, 1997 (the "Class B Agreement") (including
all rights and obligations under such sections) are hereby terminated and of
no further force and effect. All other sections and portions of the Class B
Agreement, and all other rights granted to, and all obligations of, the
parties under the Class B Agreement shall remain in full force and effect.

         1.3 CLASS C AGREEMENT. In consideration for the rights granted in
this Agreement, the Class C Purchasers agree that Section 4.2 and Section 8 of
the Class C Preferred Stock Purchase Agreement, dated as of November 17, 1994,
as amended by the Amendment and Waiver Agreement, dated as of September 19,
1995 and Amendment #1, dated October 3, 1997 ( the "Class C Agreement")
(including all rights and obligations under such sections) are hereby
terminated and of no further force and effect. All other sections and portions
of the Class C Agreement, and all other rights granted to, and all obligations
of, the parties under the Class C Agreement shall remain in full force and
effect.

         1.4 SECOND CLASS C AGREEMENT. In consideration for the rights granted
herein, the Second Class C Purchasers agree that Section 4.2 and Section 8 of
the Second Class C Preferred Stock Purchase Agreement, dated as of September
19, 1995, as amended by Amendment #1, dated October 3, 1997 (the "Second Class
C Agreement") (including all rights and obligations under such sections) are
hereby terminated and of no further force and effect. All other sections and
portions of the Second Class C Agreement, and all other rights granted to, and
all obligations of, the parties under the Second Class C Agreement shall
remain in full force and effect.

         1.5 SCIOS AGREEMENT. In consideration for the rights granted herein,
SCIOS agrees that Section 14(b), Section 15 and Section 16 of the Warrant
Agreement, dated as of May 31, 1996 (the

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"SCIOS Agreement") (including all rights and obligations under such sections)
are hereby terminated and of no further force and effect. All other sections
and portions of the SCIOS Agreement (including without limitation, Section
14(c)) and all rights granted to, and all obligations of, the parties under
the SCIOS Agreement shall remain in full force and effect.

         1.6 WARNER-LAMBERT AGREEMENT. In consideration for the rights granted
herein, Warner-Lambert agrees that Section 8 of the Stock Purchase Agreement,
dated as of July 21, 1997 (the "Warner-Lambert Agreement") (including all
rights and obligations under such section) is hereby terminated and of no
further force and effect. All other sections and portions of the
Warner-Lambert Agreement (including without limitation, Section 7), and all
rights granted to, and all obligations of the parties under the Warner-Lambert
Agreement shall remain in full force and effect.

         1.7 CRYSTAL AGREEMENT. In consideration for the rights granted
herein, Crystal agrees that as of the date hereof Section 12 of the Consulting
Agreement, dated as of March 31, 1993, as amended by Option Agreement and
Amendment #1 and Waiver, dated as of September 18, 1995 and as further amended
by the letter dated August 19, 1997 (the "Crystal Agreement") (including all
rights and obligations under such section) is terminated and of no further
force and effect.

         1.8 ORIGINAL AGREEMENT. In consideration of the rights granted
herein, the Original Agreement is hereby null and void and of no further force
and effect and the parties thereto are bound by the terms and conditions of
this Agreement.

                                    SECTION 2

                               REGISTRATION RIGHTS

         2.1 CERTAIN DEFINITIONS. As used in this Agreement, the following
terms shall have the following respective meanings:

             "CLASS A AND B CONVERSION STOCK" shall mean the Common Stock
issued or issuable upon conversion of the Class A Preferred Stock issued
pursuant to the Class A and B Agreement (the "Class A Preferred") and the
Class B Preferred Stock issued pursuant to the Class A and B Agreement and the
Class B Agreement (the "Financing Class B Preferred").

             "CLASS A AND B HOLDER" shall mean any Class A and B Purchaser or
any Additional Class B Purchaser holding Class A and B Registrable Securities
and any person holding Class A and B Registrable Securities to whom the rights
under this Section 2 have been transferred in accordance with Section 2.13 of
this Agreement.

             "CLASS A AND B REGISTRABLE SECURITIES" shall mean (i) the Class A
and B Conversion Stock; and (ii) any Common Stock of the Company issued or
issuable in respect of the Class A Preferred and Financing Class B Preferred
or other securities issued or issuable pursuant to the conversion of the Class
A Preferred and the Financing Class B Preferred, upon any stock split, stock
dividend, recapitalization, merger, consolidation or similar event (a
"Recapitalization") or any Common Stock otherwise issued or issuable with
respect to the Class A Preferred and Financing

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Class B Preferred, provided, however, that shares of Common Stock or other
securities shall no longer be treated as Class A and B Registrable Securities
after they have been sold to or through a broker or dealer or underwriter in a
public distribution or a public securities transaction, whether in a
registered offering, pursuant to Rule 144 or otherwise.

             "CLASS C CONVERSION STOCK" shall mean the Common Stock issued or
issuable upon conversion of the Class C Preferred Stock issued pursuant to the
Class C Agreement and the Second Class C Agreement (the "Class C Preferred").

             "CLASS C HOLDER" shall mean any Class C Purchaser or any Second
Class C Purchaser holding Class C Registrable Securities and any person
holding Class C Registrable Securities to whom the rights under this Section 2
have been transferred in accordance with Section 2.13 of this Agreement.

             "CLASS C REGISTRABLE SECURITIES" shall mean (i) the Class C
Conversion Stock; and (ii) any Common Stock of the Company issued or issuable
in respect of the Class C Conversion Stock or other securities issued or
issuable pursuant to the conversion of the Class C Preferred, upon any
Recapitalization or any Common Stock otherwise issued or issuable with respect
to the Class C Preferred, provided, however, that shares of Common Stock or
other securities shall no longer be treated as Class C Registrable Securities
after they have been sold to or through a broker or dealer or underwriter in a
public distribution or a public securities transaction, whether in a
registered offering, pursuant to Rule 144 or otherwise.

             "CLASS F CONVERSION STOCK" shall mean the Common Stock issued or
issuable upon conversion of the Class F Preferred Stock issued pursuant to the
Class F Agreement (the "Class F Preferred").

             "CLASS F HOLDER" shall mean any Class F Purchaser or any person
holding Class F Registrable Securities to whom the rights under this Section 2
have been transferred in accordance with Section 2.13 of this Agreement.

             "CLASS F REGISTRABLE SECURITIES" shall mean (i) the Class F
Conversion Stock; (ii) any Common Stock of the Company issued or issuable in
respect of the Class F Preferred or other securities issued or issuable
pursuant to the conversion of the Class F Preferred, upon any Recapitalization
or any Common Stock otherwise issued or issuable with respect to the Class F
Preferred, provided, however, that shares of Common Stock or other securities
shall no longer be treated as Class F Registrable Securities after they have
been sold to or through a broker or dealer or underwriter in a public
distribution or a public securities transaction, whether in a registered
offering, pursuant to Rule 144 or otherwise.

             "COMMISSION" shall mean the Securities and Exchange Commission or
any other federal agency at the time administering the Securities Act.

                                      -4-

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             "CONVERSION STOCK" shall mean the Class A and B Conversion Stock,
the Theragen Conversion Stock, the Class C Conversion Stock, the SCIOS
Conversion Stock, the Warner-Lambert Conversion Stock, the Crystal Conversion
Stock and the Class F Conversion Stock.

             "CRYSTAL CONVERSION STOCK" shall mean the Common Stock issued or
issuable upon vesting of the Restricted Stock (as defined in the Crystal
Agreement) and upon exercise of the Option (as defined in the Crystal
Agreement).

             "CRYSTAL HOLDER" shall mean Crystal (so long as he holds any
Crystal Registrable Securities) and any person holding Crystal Registrable
Securities to whom rights under this Section 2 have been transferred in
accordance with Section 2.13 of this Agreement.

             "CRYSTAL REGISTRABLE SECURITIES" shall mean (i) the Crystal
Conversion Stock; and (ii) any Common Stock of the Company issued or issuable
in respect of the Crystal Conversion Stock or other securities issued or
issuable pursuant to the vesting or conversion of the Restricted Stock or
Option, upon any Recapitalization or any Common Stock otherwise issued or
issuable with respect to the Restricted Stock or Option, provided, however,
that shares of Common Stock or other securities shall no longer be treated as
Crystal Registrable Securities after they have been sold to or through a
broker or dealer or underwriter in a public distribution or a public
securities transaction, whether in a registered offering, pursuant to Rule 144
or otherwise.

             "DEMAND HOLDER" shall mean any Class A and B Holder, Theragen
Preferred Holder, Class C Holder or Class F Holder.

             "DEMAND REGISTRABLE SECURITIES" shall mean the Class A and B
Registrable Securities, Theragen Preferred Registrable Securities, the Class C
Registrable Securities and the Class F Registrable Securities.

             "HOLDER" shall mean any Class A and B Holder, Theragen Holder,
Class C Holder, SCIOS Holder, Warner-Lambert Holder, Crystal Holder or Class F
Holder.

             "INITIATING HOLDERS" shall mean (i) Class A and B Holders of not
less than 50% of the Class A and B Registrable Securities; (ii) Theragen
Preferred Holders of greater than 50% of the Theragen Preferred Registrable
Securities; (iii) Class C Holders of not less than 50% of the Class C
Registrable Securities; or (iv) Class F Holders of not less than 50% of the
Class F Registrable Securities.

             "PREFERRED" means Class A Preferred, Class B Preferred, Class C
Preferred, the Warner-Lambert Preferred and the Class F Preferred.

             "PURCHASERS" means the Class A and B Purchasers, the Additional
Class B Purchasers, the Theragen Purchasers, the Class C Purchasers, the
Second Class C Purchasers, SCIOS, Warner-Lambert, Crystal and the Class F
Purchasers.

                                      -5-
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             "REGISTRABLE SECURITIES" means the Class A and B Registrable
Securities, the Theragen Registrable Securities, the Class C Registrable
Securities, the SCIOS Registrable Securities, the Warner-Lambert Registrable
Securities, the Crystal Registerable Securities and the Class F Registrable
Securities.

             The terms "REGISTER," "REGISTERED" and "REGISTRATION" refer to a
registration effected by preparing and filing a registration statement in
compliance with the Securities Act, and the declaration or ordering of the
effectiveness of such registration statement.

             "REGISTRATION EXPENSES" shall mean all expenses, except as
otherwise stated below, incurred by the Company in complying with Sections
2.5, 2.6 and 2.7 including, without limitation, all registration,
qualification and filing fees, printing expenses, escrow fees, fees and
disbursements of counsel for the Company, blue sky fees and expenses, the
expense of any special audits incident to or required by any such registration
(but excluding the compensation of regular employees of the Company which
shall be paid in any event by the Company) and the reasonable fees and
expenses of one counsel for all Demand Holders in the event of the exercise of
any demand registration provided for in Section 2.5.

             "RESTRICTED SECURITIES" shall mean the securities of the Company
required to bear the legend set forth in Section 2.3.

             "S-3 HOLDER" shall mean the Class A and B Holders, the Theragen
Preferred Holders, the Class C Holders, the SCIOS Holders, the Warner-Lambert
Holders and the Class F Holders.

             "S-3 INITIATING HOLDERS" shall mean (i) Class A and B Holders of
greater than 50% of the Class A and B Registrable Securities, (ii) Theragen
Preferred Holders of greater than 50% of the Theragen Preferred Registrable
Securities, (iii) Class C Holders and Class F Holders of greater than 50% of
the Class C Registrable Securities and Class F Registrable Securities, (iv)
SCIOS Holders of greater than 80% of the SCIOS Registrable Securities, or (v)
Warner-Lambert Holders of greater than 80% of the Warner-Lambert Registrable
Securities.

             "S-3 REGISTRABLE SECURITIES" shall mean Class A and B Registrable
Securities, Theragen Preferred Registrable Securities, Class C Registrable
Securities, SCIOS Registrable Securities, Warner-Lambert Registrable
Securities and Class F Registrable Securities.

             "SCIOS CONVERSION STOCK" shall mean the Common Stock issued or
issuable upon exercise of the warrant granted pursuant to the SCIOS Agreement.

             "SCIOS HOLDER" shall mean SCIOS (so long as it holds any SCIOS
Registrable Securities) and any person holding SCIOS Registrable Securities to
whom the rights under this Section 2 have been transferred in accordance with
Section 2.13 of this Agreement.

             "SCIOS REGISTRABLE SECURITIES" shall mean (i) the SCIOS
Conversion Stock; and (ii) any Common Stock of the Company issued or issuable
in respect of the SCIOS Conversion Stock or other securities issued or
issuable pursuant to the exercise of the warrant granted pursuant to

                                      -6-

<PAGE>

the SCIOS Agreement, upon any Recapitalization or Common Stock otherwise
issued or issuable with respect to the warrant granted pursuant to the SCIOS
Agreement, provided, however, that shares of Common Stock or other securities
shall no longer be treated as SCIOS Registrable Securities after they have
been sold to or through a broker or dealer or underwriter in a public
distribution or a public securities transaction, whether in a registered
offering, pursuant to Rule 144 or otherwise.

             "SECURITIES ACT" shall mean the Securities Act of 1933, as
amended, or any similar federal statute and the rules and regulations of the
Commission thereunder, all as the same shall be in effect at the time.

             "SELLING EXPENSES" shall mean all underwriting discounts, selling
commissions and stock transfer taxes applicable to the securities registered
by the Holders and, except as set forth above, all reasonable fees and
disbursements of counsel for any Holder.

             "THERAGEN COMMON CONVERSION STOCK" shall mean the Common Stock
issued pursuant the Theragen Agreement.

             "THERAGEN COMMON HOLDER" shall mean any Theragen Common Purchaser
holding Theragen Common Registrable Securities and any person holding Theragen
Common Registrable Securities to whom the rights under this Section 2 have
been transferred in accordance with Section 2.13 of this Agreement.

             "THERAGEN COMMON REGISTRABLE SECURITIES" shall mean (i) the
Theragen Common Conversion Stock; and (ii) any Common Stock of the Company
issued or issuable in respect of the Theragen Common Conversion Stock or upon
any Recapitalization, provided, however, that shares of Common Stock or other
securities shall no longer be treated as Theragen Common Registrable
Securities after they have been sold to or through a broker or dealer or
underwriter in a public distribution or a public securities transaction,
whether in a registered offering, pursuant to Rule 144 or otherwise.

             "THERAGEN CONVERSION STOCK" shall mean the Theragen Common
Conversion Stock and the Theragen Preferred Conversion Stock.

             "THERAGEN HOLDER" shall mean the Theragen Common Holder and the
Theragen Preferred Holder.

             "THERAGEN PREFERRED CONVERSION STOCK" shall mean the Common Stock
issued or issuable upon conversion of the Class B Preferred Stock issued
pursuant the Theragen Agreement (the "Theragen Preferred," and together with
the Financing Class B Preferred, the "Class B Preferred").

             "THERAGEN PREFERRED HOLDER" shall mean any Theragen Preferred
Purchaser holding Theragen Preferred Registrable Securities and any person
holding Theragen Preferred Registrable

                                      -7-

<PAGE>

Securities to whom the rights under this Section 2 have been transferred in
accordance with Section 2.13 of this Agreement.

             "THERAGEN PREFERRED REGISTRABLE SECURITIES" shall mean (i) the
Theragen Preferred Conversion Stock; and (ii) any Common Stock of the Company
issued or issuable in respect of the Theragen Preferred Conversion Stock or
other securities issued or issuable pursuant to the conversion of the Theragen
Preferred, upon any Recapitalization or any Common Stock otherwise issued or
issuable with respect to the Theragen Preferred, provided, however, that
shares of Common Stock or other securities shall no longer be treated as
Theragen Preferred Registrable Securities after they have been sold to or
through a broker or dealer or underwriter in a public distribution or a public
securities transaction, whether in a registered offering, pursuant to Rule 144
or otherwise.

             "THERAGEN REGISTRABLE SECURITIES" shall mean the Theragen Common
Registrable Securities and the Theragen Preferred Registrable Securities.

             "WARNER-LAMBERT CONVERSION STOCK" shall mean the Common Stock
issued or issuable pursuant to and the Common Stock issued or issuable upon
conversion of the preferred stock of the Company issued pursuant to the
Warner-Lambert Agreement (the "Warner-Lambert Preferred").

             "WARNER-LAMBERT HOLDER" shall mean Warner-Lambert (so long as it
holds any Warner-Lambert Registrable Securities) and any person holding
Warner-Lambert Registrable Securities to whom the rights under this Section 2
have been transferred in accordance with Section 2.13 of this Agreement.

             "WARNER-LAMBERT REGISTRABLE SECURITIES" shall mean (i) the
Warner-Lambert Conversion Stock; and (ii) any Common Stock of the Company
issued or issuable in respect of the Warner-Lambert Conversion Stock or other
securities issued or issuable pursuant to the conversion of the Warner-Lambert
Preferred, upon any Recapitalization or any Common Stock otherwise issued or
issuable with respect to the Warner-Lambert Preferred, provided, however, that
shares of Common Stock or other securities shall no longer be treated as
Warner-Lambert Registrable Securities after they have been sold to or through
a broker or dealer or underwriter in a public distribution or a public
securities transaction, whether in a registered offering, pursuant to Rule 144
or otherwise.

         2.2 RESTRICTIONS ON TRANSFERABILITY. The Preferred and the Conversion
Stock shall not be sold, assigned, transferred or pledged except upon the
conditions specified in this Section 2, which conditions are intended to
ensure compliance with the provisions of the Securities Act. Each Purchaser
will cause any proposed purchaser, assignee, transferee, or pledgee of the
Preferred or Conversion Stock held by a Purchaser to agree to take and hold
such securities subject to the provisions and upon the conditions specified in
this Section 2.

         2.3 RESTRICTIVE LEGEND. Each certificate representing the Preferred,
the Conversion Stock and any other securities issued in respect of the
Preferred or the Conversion Stock upon any stock split, stock dividend,
recapitalization, merger, consolidation or similar event, shall (unless
otherwise

                                      -8-

<PAGE>

permitted by the provisions of Section 2.4 below) be stamped or otherwise
imprinted with a legend substantially in the following form (in addition to
any legend required under applicable state securities laws):

             THE SHARES REPRESENTED BY THIS CERTIFICATE HAVE BEEN ACQUIRED
             FOR INVESTMENT AND HAVE NOT BEEN REGISTERED UNDER THE SECURITIES
             ACT OF 1933. SUCH SHARES MAY NOT BE SOLD OR TRANSFERRED IN THE
             ABSENCE OF SUCH REGISTRATION OR AN EXEMPTION FROM THE REGISTRATION
             AND PROSPECTUS DELIVERY REQUIREMENTS OF SAID ACT.

             Each Purchaser and Holder consents to the Company making a
notation on its records and giving instructions to any transfer agent of the
Preferred or the Conversion Stock in order to implement the restrictions on
transfer established in this Section 2.3.

         2.4 NOTICE OF PROPOSED TRANSFERS. The holder of each certificate
representing Restricted Securities by acceptance thereof agrees to comply in
all respects with the provisions of this Section 2.4. Prior to any proposed
sale, assignment, transfer or pledge of any Restricted Securities (other than
(i) a transfer not involving a change in beneficial ownership or (ii) in
transactions involving the distribution without consideration of Restricted
Securities by any of the Purchasers to any of its partners, or retired
partners, or to the estate of any of its partners or retired partners), unless
there is in effect a registration statement under the Securities Act covering
the proposed transfer, the holder thereof shall give written notice to the
Company of such holder's intention to effect such transfer, sale, assignment
or pledge. Each such notice shall describe the manner and circumstances of the
proposed transfer, sale, assignment or pledge in sufficient detail, and, if
requested by the Company, shall be accompanied, at such holder's expense, by
either (i) an unqualified written opinion of legal counsel who shall be, and
whose legal opinion shall be, reasonably satisfactory to the Company addressed
to the Company, to the effect that the proposed transfer of the Restricted
Securities may be effected without registration under the Securities Act, or
(ii) a "no action" letter from the Commission to the effect that the transfer
of such securities without registration will not result in a recommendation by
the staff of the Commission that action be taken with respect thereto,
whereupon the holder of such Restricted Securities shall be entitled to
transfer such Restricted Securities in accordance with the terms of the notice
delivered by the holder to the Company. It is agreed that the Company will not
request an opinion of counsel for the holder for transactions made in reliance
on Rule 144 under the Securities Act except in unusual circumstances, the
existence of which shall be determined in good faith by the Board of Directors
of the Company, and in any case the Company will not request an opinion of
counsel for the holder for transactions made in reliance on Rule 144(k) under
the Securities Act. Each certificate evidencing the Restricted Securities
transferred as above provided shall bear, except if such transfer is made
pursuant to Rule 144, the appropriate restrictive legend set forth in Section
2.3 above, except that such certificate shall not bear such restrictive legend
if in the opinion of counsel for such holder and the Company such legend is
not required in order to establish compliance with any provision of the
Securities Act.

                                      -9-

<PAGE>

         2.5      REQUESTED REGISTRATION.

                  (a) REQUEST FOR REGISTRATION. In case the Company shall
receive from Initiating Holders a written request that the Company effect any
registration, qualification or compliance with respect to Demand Registrable
Securities on a form of registration statement other than Form S-2 or Form S-3
(or any successor form to Form S-3), the Company will:

                           (i) promptly give written notice of the proposed
registration, qualification or compliance to all other Demand Holders; and

                           (ii) as soon as practicable, use its diligent
efforts to effect such registration, qualification or compliance (including,
without limitation, appropriate qualification under applicable blue sky or
other state securities laws and appropriate compliance with applicable
regulations issued under the Securities Act and any other governmental
requirements or regulations) as may be so requested and as would permit or
facilitate the sale and distribution of all or such portion of such Demand
Registrable Securities as are specified in such request, together with all or
such portion of the Demand Registrable Securities of any Demand Holders
joining in such request as are specified in a written request received by the
Company within 20 days after receipt of such written notice from the Company;
provided, however, that the Company shall not be obligated to take any action
to effect any such registration, qualification or compliance pursuant to this
Section 2.5:

                                (A) In any particular jurisdiction in which
the Company would be required to execute a general consent to service of
process in effecting such registration, qualification or compliance unless the
Company is already subject to service in such jurisdiction and except as may
be required by the Securities Act;

                                (B) On or prior to (i) December 1, 1998 if the
closing of the initial public offering of the Company's Common Stock (the
"IPO") has not occurred on or prior to such date;

                                (C) During the period starting with the date
sixty (60) days prior to the Company's estimated date of filing of, and ending
on the date six (6) months immediately following the effective date of, any
registration statement pertaining to securities of the Company (other than a
registration of securities in a Rule 145 transaction or with respect to an
employee benefit plan), provided that the Company is actively employing in
good faith all reasonable efforts to cause such registration statement to
become effective;

                                (D) Unless the anticipated aggregate offering
price, net of underwriting discounts and commissions, of all Demand Registered
Securities sought to be registered by all Initiating Holders pursuant to this
Section 2.5, would exceed $5,000,000;

                                (E) After the Company has effected three such
registrations pursuant to this subparagraph 2.5(a), and such registrations
have been declared or ordered effective and the securities offered pursuant to
such registrations have been sold;

                                      -10-
<PAGE>

                               (F) If the Company shall furnish to the
Initiating Holders a certificate signed by the President of the Company
stating that in the good faith judgment of the Board of Directors it would be
seriously detrimental to the Company or its stockholders for a registration
statement to be filed in the near future, then the Company's obligation to use
its best efforts to register, qualify or comply under this Section 2.5 shall
be deferred for a period not to exceed 90 days from the date of receipt of
written request from the Initiating Holders, provided, however, that the
Company shall not exercise the right to defer registration granted pursuant to
this paragraph (F) more than one time in any twelve month period.

         Subject to the foregoing clauses (A) through (F), the Company shall
file a registration statement covering the Demand Registrable Securities so
requested to be registered as soon as practicable after receipt of the request
or requests of the Initiating Holders.

                  (b) UNDERWRITING. In the event that a registration pursuant
to Section 2.5 is for a registered public offering involving an underwriting,
the Company shall so advise the Demand Holders as part of the notice given
pursuant to Section 2.5(a)(i). In such event, the right of any Demand Holder
to registration pursuant to Section 2.5 shall be conditioned upon such Demand
Holder's participation in the underwriting arrangements required by this
Section 2.5, and the inclusion of such Demand Holder's Registrable Securities
in the underwriting to the extent requested shall be limited to the extent
provided herein.

         The Company shall (together with all Demand Holders proposing to
distribute their securities through such underwriting) enter into an
underwriting agreement in customary form with the managing underwriter
selected for such underwriting by a majority in interest of the Initiating
Holders, but subject to the Company's reasonable approval. Notwithstanding any
other provision of this Section 2.5, if the managing underwriter advises the
Initiating Holders in writing that marketing factors require a limitation of
the number of shares to be underwritten, then (i) first the securities other
than the Demand Registrable Securities and (ii) next the securities requested
to be registered by the Company, shall be excluded from such registration. If
a limitation of the number of shares is thereafter still required, the
Initiating Holders shall so advise all Demand Holders of Registrable
Securities and the number of shares of Registrable Securities that may be
included in the registration and underwriting shall be allocated among all
Demand Holders thereof in proportion, as nearly as practicable, to the
respective amounts of Registrable Securities held by such Demand Holders at
the time of filing the registration statement. No Registrable Securities
excluded from the underwriting by reason of the underwriter's marketing
limitation shall be included in such registration. To facilitate the
allocation of shares in accordance with the above provisions, the Company or
the underwriters may round the number of shares allocated to any Demand Holder
to the nearest 100 shares.

         If any Demand Holder of Registrable Securities disapproves of the
terms of the underwriting, such person may elect to withdraw therefrom by
written notice to the Company, the managing underwriter and the Initiating
Holders. Any securities excluded or withdrawn from such underwriting, in the
event that such underwriting represents the initial underwritten public
offering of the Company's securities, shall be withdrawn from such
registration, and shall not be transferred

                                      -11-

<PAGE>

in a public distribution prior to 180 days after the effective date of the
registration statement relating thereto, or such other shorter period of time
as the underwriters may require. If by the withdrawal of such Registrable
Securities a greater number of Registrable Securities held by other Demand
Holders may be included in such registration (up to the maximum of any
limitation imposed by the underwriters), then the Company shall offer to all
Demand Holders who have included Registrable Securities in the registration
the right to include additional Registrable Securities calculated in the same
manner used in this Section 2.5(b) in determining the allocation of shares to
be sold when subject to an underwriter limitation.

         2.6      COMPANY REGISTRATION.

                  (a) NOTICE OF REGISTRATION. If at any time or from time to
time the Company shall determine to register any of its securities, either for
its own account or the account of a security holder or holders, other than (i)
a registration relating solely to employee benefit plans, or (ii) a
registration relating solely to a Commission Rule 145 transaction, the Company
will:

                      (i) give to each Holder at least 30 days prior written
notice thereof; and

                      (ii) include in such registration (and any related
qualification under blue sky laws or other compliance), and in any
underwriting involved therein, all the Registrable Securities specified in a
written request or requests, made within 20 days after receipt of such written
notice from the Company, by any Holder;

provided, however, that the Company shall not be obligated to take such
actions with respect to any SCIOS Holder if such registration is to be
effected on any form other than a registration statement or Form S-3 (or any
successor form to Form S-3).

                  (b) UNDERWRITING. If the registration of which the Company
gives notice is for a registered public offering involving an underwriting,
the Company shall so advise the Holders as a part of the written notice given
pursuant to Section 2.6(a)(i). In such event the right of any Holder to
registration pursuant to Section 2.6 shall be conditioned upon such Holder's
participation in such underwriting and the inclusion of Registrable Securities
in the underwriting to the extent provided herein. All Holders proposing to
distribute their securities through such underwriting shall (together with the
Company and the other holders distributing their securities through such
underwriting) enter into an underwriting agreement in customary form with the
managing underwriter selected for such underwriting by the Company.
Notwithstanding any other provision of this Section 2.6, if the managing
underwriter determines that marketing factors require a limitation of the
number of shares to be underwritten, the managing underwriter may limit (or
exclude entirely) the shares held by other holders of registration rights, and
following exclusion of such shares, the Registrable Securities to be included
in such registration; provided, however, in no event shall any shares being
sold by a stockholder exercising a demand registration right similar to that
granted in Section 2.5 be excluded from such offering in a manner inconsistent
with provisions similar to Section 2.5(b). The Company shall advise all
Holders and other holders exercising their registration rights to distribute
their securities through such underwriting of any such limitation, and shall
first limit (or exclude entirely) the shares held by holders of registration
rights (other than the Holders), and following exclusion of

                                      -12-

<PAGE>

such shares, the number of shares of Registrable Securities that may be
included in the registration and underwriting shall be allocated among all
Holders exercising their registration rights in proportion, as nearly as
practicable, to the respective amounts of Registrable Securities held by such
Holders. If any Holder or holder disapproves of the terms of any such
underwriting, it may elect to withdraw therefrom by written notice to the
Company and the managing underwriter. Any securities excluded or withdrawn
from such underwriting, in the event that such underwriting represents the
initial underwritten public offering of the Company's securities, shall be
withdrawn from such registration, and shall not be transferred in a public
distribution prior to 180 days after the effective date of the registration
statement relating thereto, or such other shorter period of time as the
underwriters may require.

                  (c) RIGHT TO TERMINATE REGISTRATION. The Company shall have
the right to terminate or withdraw any registration initiated by it under this
Section 2.6 prior to the effectiveness of such registration whether or not any
Holder has elected to include securities in such registration.

         2.7      REGISTRATION ON FORM S-3.

                  (a) If any S-3 Initiating Holder or Holders requests that
the Company file a registration statement on Form S-3 (or any successor form
to Form S-3) for a public offering of shares of the S-3 Registrable
Securities, and the Company is a registrant entitled to use Form S-3 to
register the S-3 Registrable Securities for such an offering, the Company
shall: (i) promptly give written notice of the proposed registration to all
other S-3 Holders of Registrable Securities and (ii) use its best efforts to
cause, as soon as practicable, all S-3 Registrable Securities to be registered
as may be so requested for the offering on such form and to cause such S-3
Registrable Securities to be qualified in such jurisdictions as the S-3
Initiating Holder or other S-3 Holders may reasonably request. The substantive
provisions of Section 2.5(b) shall be applicable to each registration
initiated under this Section 2.7.

                  (b) Notwithstanding the foregoing, the Company shall not be
obligated to take any action pursuant to this Section 2.7: (i) in any
particular jurisdiction in which the Company would be required to execute a
general consent to service of process in effecting such registration,
qualification or compliance unless the Company is already subject to service
in such jurisdiction and except as may be required by the Securities Act; or
(ii) if the Company shall furnish to such S-3 Initiating Holders a certificate
signed by the President of the Company stating that in the good faith judgment
of the Board of Directors it would be seriously detrimental to the Company or
its stockholders for registration statements to be filed in the near future,
then the Company's obligation to use its best efforts to file a registration
statement shall be deferred for a period not to exceed 90 days from the
receipt of the request to file such registration by such S-3 Initiating
Holders, provided, however, that the Company shall not exercise the right to
defer registration granted by this subparagraph (b)(ii) more than once in any
twelve month period.

                  (c) Notwithstanding the foregoing, (i) this Section 2.7
shall not apply to any SCIOS Holder, and no SCIOS Holder shall have any right
or obligation under this Section 2.7 until

                                      -13-

<PAGE>

June 1, 1999 and (ii) the Company shall not be required to include SCIOS
Registration Securities in more than one (1) registration pursuant to Section
2.7.

                  (d) Notwithstanding the foregoing, (i) this Section 2.7
shall apply to any Warner-Lambert Holder, and Warner-Lambert Holder shall have
rights and obligations pursuant to this Section 2.7, only if such
Warner-Lambert Holder is unable to sell the Warner-Lambert Registrable
Securities within eighteen (18) months after the end of the Restriction Period
(as defined in the Warner-Lambert Agreement) pursuant to Rules 144(k) (or a
successor rule) under the Securities Act or pursuant to Section 2.6, (ii) the
Company shall not be required to include Warner-Lambert Registrable Securities
in more than one (1) registration pursuant to this Section 2.7, and (iii) the
Company shall not be required to include any Warner-Lambert Registrable
Securities in any registration pursuant to this Section 2.7 unless the
expected net proceeds to Warner-Lambert exceeds $5,000,000.

         2.8      EXPENSES OF REGISTRATION.

                  (a) All Registration Expenses incurred in connection with
all registrations pursuant to Sections 2.5 and 2.6, shall be borne by the
Company. Unless otherwise stated, all Selling Expenses relating to securities
registered on behalf of the Holders and all other Registration Expenses shall
be borne by the Holders of such securities pro rata on the basis of the number
of shares so registered.

                  (b) All Registration Expenses and Selling Expenses incurred
in connection with a registration pursuant to Section 2.7 shall be borne pro
rata by the Holder or Holders requesting the registration on Form S-2 or Form
S-3 according to the number of Registrable Securities included in such
registration.

         2.9      REGISTRATION PROCEDURES. The Company will keep each Holder
whose Registrable Securities are included in any registration pursuant to this
Agreement advised as to the initiation and completion of such registration. At
its expense the Company will with all deliberate speed:

                  (a) Prepare and file with the Commission a registration
statement with respect to such securities and use its best efforts to cause
such registration statement to become and remain effective for at least one
hundred eighty (180) days or until the distribution described in the
Registration Statement has been completed;

                  (b) Furnish to the Holders participating in such
registration and to the underwriters of the securities being registered such
reasonable number of copies of the registration statement, preliminary
prospectus, final prospectus and such other documents as such underwriters may
reasonably request in order to facilitate the public offering of such
securities;

                  (c) Prepare and file with the Commission such amendments and
supplements to such registration statement and the prospectus used in
connection with such registration statements as may be necessary to comply
with the provisions of the Securities Act with respect to the disposition of
all securities covered by such registration statement;

                                      -14-

<PAGE>

                  (d) Use its best efforts to register and qualify the
securities covered by such registration statement under such other securities
or Blue Sky laws of such jurisdictions as shall be reasonably requested by the
Holders, provided that the Company shall not be required in connection
therewith or as a condition thereto to qualify to do business or to file a
general consent to service of process in any such states or jurisdictions; and

                  (e) In the event of any underwritten public offering, enter
into and perform its obligations under an underwriting agreement, in usual and
customary form, with the managing underwriter of such offering. Each Holder
participating in such underwriting shall also enter into and perform its
obligations under such an agreement.

         2.10      INDEMNIFICATION.

                  (a) The Company will indemnify each Holder, each of its
officers and directors and partners, and each person controlling such Holder
within the meaning of Section 15 of the Securities Act, with respect to which
registration, qualification or compliance has been effected pursuant to the
Agreement, and each underwriter, if any, and each person who controls any
underwriter within the meaning of Section 15 of the Securities Act, against
all expenses, claims, losses, damages or liabilities (or actions in respect
thereof), including any of the foregoing incurred in settlement of any
litigation, commenced or threatened, arising out of or based on any untrue
statement (or alleged untrue statement) of a material fact contained in any
registration statement, prospectus, offering circular or other document, or
any amendment or supplement thereto, incident to any such registration,
qualification or compliance, or based on any omission (or alleged omission) to
state therein a material fact required to be stated therein or necessary to
make the statements therein, in light of the circumstances in which they were
made, not misleading, or any violation by the Company of the Securities Act or
any rule or regulation promulgated under the Securities Act applicable to the
Company in connection with any such registration, qualification or compliance,
and the Company will reimburse each such Holder, each of its officers and
directors, and each person controlling such Holder, each such underwriter and
each person who controls any such underwriter, for any legal and any other
expenses reasonably incurred in connection with investigating, preparing or
defending any such claim, loss, damage, liability or action, provided that the
Company will not be liable in any such case to the extent that any such claim,
loss, damage, liability or expense arises out of or is based on any untrue
statement or omission or alleged untrue statement or omission, made in
reliance upon and in conformity with written information furnished to the
Company by an instrument duly executed by such Holder, controlling person or
underwriter and stated to be specifically for use therein.

                  (b) Each Holder will, if Registrable Securities held by such
Holder are included in the securities as to which such registration,
qualification or compliance is being effected, indemnify the Company, each of
its directors and officers, each underwriter, if any, of the Company's
securities covered by such a registration statement, each person who controls
the Company or such underwriter within the meaning of Section 15 of the
Securities Act, and each other such Holder, each of its officers, directors
and partners and each person controlling such Holder within the meaning of
Section 15 of the Securities Act, against all claims, losses, damages and
liabilities (or actions in

                                      -15-

<PAGE>

respect thereof) arising out of or based on any untrue statement (or alleged
untrue statement) of a material fact contained in any such registration
statement, prospectus, offering circular or other document, or any omission
(or alleged omission) to state therein a material fact required to be stated
therein or necessary to make the statements therein not misleading, and will
reimburse the Company, such Holders, such directors, officers, partners,
persons, underwriters or control persons for any legal or any other expenses
reasonably incurred in connection with investigating or defending any such
claim, loss, damage, liability or action, in each case to the extent, but only
to the extent, that such untrue statement (or alleged untrue statement) or
omission (or alleged omission) is made in such registration statement,
prospectus, offering circular or other document in reliance upon and in
conformity with written information furnished to the Company by an instrument
duly executed by such Holder and stated to be specifically for use therein. In
no event shall any indemnity under this Section 2.10 exceed the proceeds from
the offering received by such Holder.

                  (c) Each party entitled to indemnification under this
Section 2.10 (the "Indemnified Party") shall give notice to the party required
to provide indemnification (the "Indemnifying Party") promptly after such
Indemnified Party has actual knowledge of any claim as to which indemnity may
be sought, and shall permit the Indemnifying Party to assume the defense of
any such claim or any litigation resulting therefrom, provided that counsel
for the Indemnifying Party, who shall conduct the defense of such claim or
litigation, shall be approved by the Indemnified Party (whose approval shall
not unreasonably be withheld), and the Indemnified Party may participate in
such defense at such party's expense, and provided further that the failure of
any Indemnified Party to give notice as provided herein shall not relieve the
Indemnifying Party of its obligations under this Section 2.10 unless the
failure to give such notice is materially prejudicial to an Indemnifying
Party's ability to defend such action and provided further, that the
Indemnifying Party shall not assume the defense for matters as to which there
is a conflict of interest or separate and different defenses. No Indemnifying
Party, in the defense of any such claim or litigation, shall, except with the
consent of each Indemnified Party, consent to entry of any judgment or enter
into any settlement which does not include as an unconditional term thereof
the giving by the claimant or plaintiff to such Indemnified Party of a release
from all liability in respect to such claim or litigation. No Indemnifying
Party shall be liable for indemnification hereunder with respect to any
settlement or consent to judgment, in connection with any claim or litigation
to which these indemnification provisions apply, that has been entered into
without the prior consent of the Indemnifying Party (which consent will not be
unreasonably withheld).

                  (d) If the indemnification provided for in this Section 2.10
is held by a court of competent jurisdiction to be unavailable to an
Indemnified Party with respect to any losses, claims, damages or liabilities
referred to herein, the Indemnifying Party, in lieu of indemnifying such
Indemnified Party thereunder, shall to the extent permitted by applicable law
contribute to the amount paid or payable by such Indemnified Party as a result
of such loss, claim, damage or liability in such proportion as is appropriate
to reflect the relative fault of the Indemnifying Party on the one hand and of
the Indemnified Party on the other in connection with the untrue statement or
omission or alleged untrue statement or omission that resulted in such loss,
claim, damage or liability, as well as any other relevant equitable
considerations. The relative fault of the Indemnifying Party and of the
Indemnified Party shall be determined by a court of law by reference to, among
other things,

                                      -16-

<PAGE>

whether the untrue or alleged untrue statement of a material fact or the
omission to state a material fact relates to information supplied by the
Indemnifying Party or by the Indemnified Party and the parties' relative
intent, knowledge, access to information and opportunity to correct or prevent
such statement or omission; provided, that in no event shall any contribution
by a Holder hereunder exceed the proceeds from the offering received by such
Holder.

         2.11     INFORMATION BY HOLDER. The Holder or Holders of Registrable
Securities included in any registration shall furnish to the Company such
information regarding such Holder or Holders, the Registrable Securities held
by it or them and the distribution proposed by such Holder or Holders as the
Company may request in writing and as shall be required in connection with any
registration, qualification or compliance referred to in this Section 2.11.

         2.12     RULE 144 REPORTING. With a view to making available the
benefits of certain rules and regulations of the Commission that may at any
time permit the sale of the Restricted Securities to the public without
registration, after such time as a public market exists for the Common Stock
of the Company, the Company agrees to use its diligent efforts to:

                  (i) Make and keep public information available, as those
terms are understood and defined in Rule 144 under the Securities Act, at all
times after the effective date that the Company becomes subject to the
reporting requirements of the Securities Act or the Securities Exchange Act of
1934, as amended (the "Exchange Act");

                  (ii) File with the Commission in a timely manner all reports
and other documents required of the Company under the Securities Act and the
Exchange Act (at any time after it has become subject to such reporting
requirements); and

                  (iii) So long as a Holder owns any Restricted Securities,
furnish to the Holder forthwith upon request a written statement by the
Company as to its compliance with the reporting requirements of Rule 144 (at
any time after ninety (90) days after the effective date of the first
registration statement filed by the Company for an offering of its securities
to the general public), and of the Securities Act and the Exchange Act (at any
time after it has become subject to such reporting requirements), a copy of
the most recent annual or quarterly report of the Company, and such other
reports and documents of the Company and other information in the possession
of or reasonably obtainable by the Company as a Holder may reasonably request
in availing itself of any rule or regulation of the Commission allowing a
Holder to sell any such securities without registration.

         2.13     TRANSFER OF REGISTRATION RIGHTS. The rights to cause the
Company to register securities granted Purchasers under Sections 2.5, 2.6 and
2.7 may be assigned (i) in connection with transactions involving the
distribution without consideration of Registrable Securities by any of the
Purchasers to any of its partners, affiliates (as defined under the Securities
Act), members or retired partners or the estate of any of its partners,
affiliates (as defined under the Securities Act), members or retired partners,
or (ii) to a transferee or assignee reasonably acceptable to the Company in
connection with any transfer or assignment of Registrable Securities by a
Purchaser, provided that (a) such transfer may otherwise be effected in
accordance with applicable securities laws,

                                      -17-

<PAGE>

Sections 2.3 and 2.4 and as to Warner-Lambert, Section 7 of the Warner-Lambert
Agreement and as to SCIOS, Section 14(c) of the SCIOS Agreement, and (b) such
assignee or transferee acquires at least 100,000 shares of the applicable
Conversion Stock (adjusted for stock splits, stock dividends, stock
recombinations and the like after the date of this Agreement).

         2.14     STANDOFF AGREEMENT. Each Holder agrees in connection with
the Company's initial public offering of the Company's securities, (1) not to
sell, make short sale of, loan, grant any options for the purchase of, or
otherwise dispose of any securities of the Company (other than those
securities included in the registration) without the prior written consent of
the Investor or the underwriters managing such initial underwritten public
offering of the Company's securities (the "Managing Underwriter") for one
hundred eighty (180) days from the effective date of such registration, and
(2) further agrees to execute any agreement reflecting (1) above as may be
requested by the Managing Underwriter, provided that the officers and
directors of the Company who own stock of the Company also agree to such
restrictions. Each Holder shall cause any proposed purchaser, assignee,
transferee or pledgee of any shares held by such Holder to agree to take and
hold such securities subject to this Section 2.14.

                                    SECTION 3

                                  MISCELLANEOUS

         3.1      GOVERNING LAW. This Agreement shall be governed in all
respects by the internal laws of the State of Delaware.

         3.2      SUCCESSORS AND ASSIGNS. Except as otherwise provided herein,
the provisions hereof shall inure to the benefit of, and be binding upon, the
successors, assigns, heirs, executors and administrators of the parties hereto.

         3.3      ENTIRE AGREEMENT; AMENDMENT. This Agreement constitutes the
full and entire understanding and agreement and supersedes any existing
agreement between the parties with regard to the subject matter hereof,
including without limitation any understanding or agreement relating to
registration set forth in the Class A and B Agreement, the Class B Agreement,
the Theragen Agreement, the Class C Agreement, the Second Class C Agreement,
the SCIOS Agreement, the Crystal Agreement, Section 8 of the Warner-Lambert
Agreement and in Section 14(c) (but excluding the restrictions on transfer
and/or legend requirements) of the SCIOS Agreement. Except as expressly
provided herein, neither this Agreement nor any term hereof may be amended,
waived, discharged or terminated other than by a written instrument signed by
the party against whom enforcement of any such amendment, waiver, discharge or
termination is sought; provided, however, that (i) both (a) Demand Holders of
sixty-six and two thirds percent (66-2/3%) of Class A and B Registrable
Securities, Theragen Preferred Registrable Securities and Class C Registrable
Securities and (b) Demand Holders of sixty-six and two-thirds percent
(66-2/3%) of Class A and B Registrable Securities, Theragen Preferred
Registrable Securities, Class C Registrable Securities and Class F Registrable
Securities may, with the Company's written consent, waive, modify, or amend on
behalf of all holders any provision of Section 2.5, (ii) Holders of sixty-six
and two thirds percent (66-2/3%) of the Registrable Securities may, with the
Company's written consent, waive, modify, or amend on

                                      -18-

<PAGE>

behalf of all holders any provision of Section 2.6, (iii) both (a) S-3 Holders
of sixty-six and two-thirds percent (66-2/3%) of Class A and B Registrable
Securities, Theragen Preferred Registrable Securities, Class C Registrable
Securities and Warner-Lambert Registrable Securities and (b) S-3 Holders of
sixty-six and two-thirds percent (66-2/3%) of Class A and B Registrable
Securities, Theragen Preferred Registrable Securities, Class C Registrable
Securities, Warner-Lambert Registrable Securities and Class F Registrable
Securities may, with the Company's written consent, waive, modify, or amend on
behalf of all holders any provision of Section 2.7 (other than Section 2.7(c)
and Section 2.7(d)), (iv) SCIOS may, with the Company's written consent,
waive, modify, or amend Section 1.5 and Section 2.7(c), (v) Warner-Lambert
may, with the Company's written consent, waive, modify, or amend Section 1.6
and Section 2.7(d), (vi) the Holders of sixty-six and two thirds percent
(66-2/3%) of the Class A Preferred Stock and Class B Preferred Stock (on an as
converted to Common Stock basis) issued pursuant to the Class A and B
Agreement may, with the Company's written consent, waive, modify, or amend
Section 1.1, (vii) the Holders of sixty-six and two thirds percent (66-2/3%)
of the Class B Preferred Stock (on an as converted to Common Stock basis)
issued pursuant to the Class B Agreement may, with the Company's written
consent, waive, modify, or amend Section 1.2, (viii) the Holders of a majority
of the Class C Preferred Stock (on an as converted to Common Stock basis)
issued pursuant to the Class C Agreement may, with the Company's written
consent, waive, modify, or amend Section 1.3, (ix) the Holders of a majority
of the Class C Preferred Stock (on an as converted to Common Stock basis)
issued pursuant to the Second Class C Agreement may, with the Company's
written consent, waive, modify, or amend Section 1.4, (x) the Holders of a
majority of the Crystal Conversion Stock may, with the Company's written
consent, waive, modify, or amend Section 1.7 and (xi) Holders of a majority of
Registrable Securities may, with the Company's written consent, waive, modify,
or amend Section 2 (other than Section 2.5, Section 2.6 and Section 2.7) and
Section 3 (other than Section 3.3(i), (ii), (iii), (iv), (v), through (x)).
Notwithstanding the above, in the event of an amendment or a waiver that would
adversely affect the holders of Class F Convertible Preferred Stock in a
manner differently than holders of Preferred Stock generally, then the
approval of a majority of the then outstanding Class F Preferred Stock is
required.

         3.4      NOTICES. All notices and other communications required or
permitted hereunder shall be in writing and shall be mailed by registered or
certified mail, postage prepaid, or otherwise delivered by hand or by
messenger, addressed (a) if to a Purchaser, at such address as the Purchaser
shall have furnished to the Company in writing, (b) if to any other Holder at
such address as such Holder shall have furnished the Company in writing, or,
until any such Holder so furnishes an address to the Company, then to and at
the address of the last Holder of such shares who has so furnished an address
to the Company, or (c) if to the Company, at 5615 Fishers Lane, Rockville,
Maryland 20852 addressed to the attention of the Chief Executive Officer, or
at such other address as the Company shall have furnished to the Purchasers.
Each such notice or other communication shall for all purposes of this
Agreement be treated as effective or having been given when delivered if
delivered personally or sent by telegram, telefax or telex (receipt
confirmed), or, if sent by mail, at the earlier of its receipt or 72 hours
after the same has been deposited in a regularly maintained receptacle for the
deposit of the United States mail, addressed and mailed as described above, or
if sent by electronic mail, then one business day following delivery.
Notwithstanding anything in this

                                      -19-

<PAGE>

Agreement to the contrary, a consent, waiver, modification or amendment
delivered by electronic mail shall be effective.

         3.5      DELAYS OR OMISSIONS. Except as expressly provided herein, no
delay or omission to exercise any right, power or remedy accruing to any
holder of any Registrable Securities, upon any breach or default of the
Company under this Agreement, shall impair any such right, power or remedy of
such holder nor shall it be construed to be a waiver of any such breach or
default, or an acquiescence therein, or of or in any similar breach or default
thereafter occurring; nor shall any waiver of any single breach or default be
deemed a waiver of any other breach or default theretofore or thereafter
occurring. Any waiver, permit, consent or approval of any kind or character on
the part of any holder of any breach or default under this Agreement, or any
waiver on the part of any holder of any provisions or conditions of this
Agreement, must be in writing and shall be effective only to the extent
specifically set forth in such writing and as set forth in Section 3.3 above.
All remedies, either under this Agreement or by law or otherwise afforded to
any holder, shall be cumulative and not alternative. Except as expressly
provided herein, no delay or omission to exercise any right, power, or remedy
occurring to the Company, upon any breach or default of the holder under this
Agreement, shall impair any such right, power, or remedy of the Company, nor
shall it be construed to be a waiver of any such breach or default, or an
acquiescence therein, or of or in any similar breach or default thereafter
occurring; nor shall any waiver of any single breach or default be deemed a
waiver of any other breach or default theretofore or thereafter occurring. Any
waiver, permit, consent or approval of any kind or character on the part of
the Company of any breach of default under this Agreement, or any waiver on
the part of the Company of any provisions or conditions of this Agreement,
must be in writing and shall be effective only to the extent specifically set
forth in such writing. All remedies, either under this Agreement or by law or
otherwise afforded to the Company, shall be cumulative and not alternative.

         3.6      EXPENSES. The Company and each Purchaser shall bear its own
expenses incurred on its behalf with respect to this Agreement and the
transactions contemplated hereby (except as otherwise provided herein) and any
amendments or waivers hereto.

         3.7      ATTORNEYS' FEES. In the event of any litigation in a court
of competent jurisdiction arising in connection with this Agreement and the
transactions contemplated hereby, the prevailing party in judgment shall be
entitled to recover reasonable legal fees and costs in connection with such
action.

         3.8      COUNTERPARTS. This Agreement may be executed in any number
of counterparts, each of which shall be enforceable against the parties
actually executing such counterparts, and all of which together shall
constitute one instrument.

         3.9      SEVERABILITY. In the event that any provision of this
Agreement becomes or is declared by a court of competent jurisdiction to be
illegal, unenforceable or void, this Agreement shall continue in full force
and effect without said provision; provided that no such severability shall be
effective if it materially changes the economic benefit of this Agreement to
any party.

                                      -20-

<PAGE>

         3.10     TITLES AND SUBTITLES. The titles and subtitles used in this
Agreement are used for convenience only and are not considered in construing
or interpreting this Agreement.

         3.11     INAPPLICABILITY OF CERTAIN SECTIONS TO WARNER-LAMBERT.
Sections 2.2, 2.3 and 2.4 shall not apply to the Warner-Lambert Preferred and
the Warner-Lambert Conversion Stock, and instead the provisions of Section 7
of the Warner-Lambert Agreement shall continue to govern the transferability
of such shares. All provisions of the Warner-Lambert Agreement (except Section
8, which is superseded by this Agreement) shall continue in full force and
effect.

                                      -21-
<PAGE>

         The foregoing New Agreement is hereby executed as of the date first
written above.

                             "COMPANY"

                             GENVEC, INC.
                             a Delaware corporation

                             By:      /s/ Paul Fischer
                                      ----------------------------------------
                                      Paul Fischer, Ph.D.
                                      President and Chief Executive Officer

                             ARCH VENTURE FUND, LIMITED PARTNERSHIP

                             By: ARCH Development Corporation
                                 General Partner

                             By:      /s/ Steven Lazarus
                                      ----------------------------------------
                                      Name:
                                      Title:

                             ARCH VENTURE FUND II, L.P.

                             By:ARCH Management Partners II, L.P.
                             General Partner

                             By:ARCH Venture Partners, L.P.
                                            General Partner

                             By:ARCH Venture Corporation
                                            General Partner

                             By:      /s/ Steven Lazarus
                                      ----------------------------------------
                                      Name:
                                      Title:

                             BETTY S. BARDIGE

                             By:      /s/ Richard Segal
                                      ----------------------------------------
                                                     Richard D. Segal
                                                     Attorney-In-Fact

               [AMENDED & RESTATED REGISTRATION RIGHTS AGREEMENTS]

                                            -22-
<PAGE>

                             EDWARD BENZ

                             By:      /s/ Edward Benz
                                      ----------------------------------------

                             BIOTECH GROWTH SA

                             By:      /s/ H. Graf and /s/A. B
                                      ----------------------------------------
                                      Name:
                                      Title:

                             CANAAN CAPITAL LIMITED PARTNERSHIP

                             By:      Canaan Capital Management L.P.
                                      General Partner

                             By:      Canaan Capital Partners L.P.
                                      General Partner

                             By:      /s/ Harry Rein
                                      ----------------------------------------
                                      Harry T.  Rein
                                      Managing General Partner

                             CANAAN CAPITAL OFFSHORE LIMITED
                                      PARTNERSHIP, C.V.

                             By:      Canaan Capital Management L.P.
                                      General Partner

                             By:      Canaan Capital Partners L.P.
                                      General Partner

                             By:      /s/ Harry Rein
                                      ----------------------------------------
                                      Harry T. Rein
                                      Managing General Partner

               [AMENDED & RESTATED REGISTRATION RIGHTS AGREEMENT]

                                       -23-
<PAGE>

                             CANAAN S.B.I.C., L.P.

                             By:      Canaan S.B.I.C. Partners, L.P.
                                      General Partner

                             By:      /s/ Harry Rein
                                      ----------------------------------------
                                      Harry T. Rein
                                      Managing General Partner

                             WESLEY CHURCH

                             /s/ Wesley K. Church
                             -------------------------------------------------

                             CIP CAPITAL L.P.

                             By:      /s/ Joseph M. Corr
                                      ----------------------------------------
                                      Name:
                                      Title:

                             THE CIT GROUP/VENTURE CAPITAL, INC.

                             By:      /s/ Bruce Schnekinvin
                                      ----------------------------------------
                                      Name:
                                      Title:

                             MARTIN D. CLEARY

                             /s/ Martin D. Cleary
                             -------------------------------------------------

                             HERBERT J. CONRAD

                             /s/ Herbert J. Conrad
                             -------------------------------------------------

               [AMENDED & RESTATED REGISTRATION RIGHTS AGREEMENT]

                                         -24-
<PAGE>

                             DIFCO, INC.

                             By:
                                     -----------------------------------------
                                     Name:
                                     Title:

                             ENTERPRISE DEVELOPMENT FUND, L.P.

                             By:     /s/ Thomas Porter
                                     -----------------------------------------
                                     Thomas S. Porter
                                     General Partner

                             ENTERPRISE DEVELOPMENT FUND LIMITED
                                      PARTNERSHIP

                             By:
                                     -----------------------------------------
                                     Thomas S. Porter
                                     General Partner

                             ENTERPRISE DEVELOPMENT FUND LIMITED
                                     PARTNERSHIP

                             By:
                                     -----------------------------------------
                                      Thomas S. Porter
                                      General Partner

                             CHRISTOPHER EVANS

                             -------------------------------------------------

               [AMENDED & RESTATED REGISTRATION RIGHTS AGREEMENT]

                                          -25-
<PAGE>

                             DAVID J. FINK

                             -------------------------------------------------

                             FOURTH GENERATION PARTNERS

                             By:      /s/ Richard Segal
                                     -----------------------------------------
                                      Richard D. Segal
                                      Managing Partner

                             GENENTECH, INC.

                             By:      /s/ Cynthia J. Ladd
                                     -----------------------------------------
                                      Name:  Cynthia J. Ladd
                                      Title:    Vice President, Corporate Law

                             JOSEPH C. GLOROSIO, III

                             /s/ Joseph C. Glorosio, III
                             -------------------------------------------------

                             HILLMAN MEDICAL VENTURES 1992 L.P.

                             By:      Hillman/Dover Limited
                                      Partnership, General Partner

                             By:      Wilmington Securities, Inc.
                                      General Partner of Hillman/Dover Limited
                                      Partnership

                             By:      /s/ Richard H. Brown
                                     -----------------------------------------
                                      Darlene Clarke
                                      Vice President

               [AMENDED & RESTATED REGISTRATION RIGHTS AGREEMENT]

                                           -26-
<PAGE>

                             HILLMAN MEDICAL VENTURES 1993 L.P.

                             By:      Hillman/Dover Limited
                                      Partnership, General Partner

                             By:      Wilmington Securities, Inc.
                                      General Partner of Hillman/Dover Limited
                                      Partnership

                             By:      /s/ Richard H. Brown
                                      ----------------------------------------
                                      Darlene Clarke
                                      Vice President

                             HILLMAN MEDICAL VENTURES 1994 L.P.

                             By:      Hillman/Dover Limited Partnership
                                      General Partner

                             By:      Wilmington Securities, Inc.
                                      General Partner of Hillman/Dover Limited
                                      Partnership

                             By:      /s/ Richard H. Brown
                                      ----------------------------------------
                                      Darlene Clarke
                                      Vice President

                             LEAF HUANG

                             /s/ Leaf Huang
                             -------------------------------------------------

                             KATHERINE B. KAUFMAN

                             /s/ Katherine B. Kaufman
                             -------------------------------------------------

                             WILMA P. MCCLEVE

                             /s/ Wilma P. McCleve
                             -------------------------------------------------

               [AMENDED & RESTATED REGISTRATION RIGHTS AGREEMENT]

                                      -27-
<PAGE>

                             MINDFUL PARTNERS

                             By:      /s/ Stuart Rudick
                                      ----------------------------------------
                                      Stuart Rudick
                                      General Partner

                             HENRY F. & RUTH F. PEAR, TENANTS IN
                                     ENTIRETIES

                             By:      /s/ Henry F. Pear
                                      ----------------------------------------
                                      Henry F. Pear

                             By:      /s/ Ruth F. Pear
                                      ----------------------------------------
                                      Ruth F. Pear

                             PRINCE VENTURE PARTNERS III, L.P.

                             By:      PRINCE VENTURE, L.P.
                                      General Partner

                             By:      /s/ Gregory F. Zaic
                                      ----------------------------------------
                                      Gregory Zaic
                                      General Partner

                             PRISM PARTNERS I

                             By:      /s/ Jerard M. Weintraub
                                      ----------------------------------------
                                      Jerry Weintraub
                                      General Partner

               [AMENDED & RESTATED REGISTRATION RIGHTS AGREEMENT]

                                      -28-
<PAGE>

                             QUAI LIMITED

                             By:      /s/ D. Liardet
                                      ----------------------------------------
                                      Dominique Liardet
                                      Attorney-In-Fact

                             PAUL ROBBINS

                             /s/ Paul Robbins
                             -------------------------------------------------

                             JOEL SCHUR

                             /s/ Joel Schur
                             -------------------------------------------------

                             SIERRA VENTURE IV, L.P.

                             By:      SV ASSOCIATES IV, L.P.
                                      General Partner

                             By:      /s/ Petri Vainio
                                      ----------------------------------------
                                      Petri Vainio
                                      General Partner

                             SIERRA VENTURES INTERNATIONAL IV, L.P.

                             By:      SV ASSOCIATES IV, L.P.
                                      General Partner

                             By:      /s/ Petri Vainio
                                      ----------------------------------------
                                      Petri Vainio
                                      General Partner

               [AMENDED & RESTATED REGISTRATION RIGHTS AGREEMENT]

                                       -29-
<PAGE>

                             JERRY W. SMITH, PH.D.

                             /s/ Jerry W. Smith
                             -------------------------------------------------

                             STATE OF MICHIGAN RETIREMENT SYSTEM

                             By:      State Treasurer of the State of Michigan,
                                      Custodian of the Michigan Public School
                                      Employees' Retirement System, State
                                      Employees' Retirement System, Michigan
                                      State Police Retirement System, and
                                      Michigan Judges Retirement System

                             By:      /s/ Linda Rose
                                      ----------------------------------------
                                      Paul E. Rice
                                      Administrator, Alternative
                                      Investment Division

                             PETER A. WARD

                             /s/ Peter Ward
                             -------------------------------------------------

                             WARNER-LAMBERT COMPANY

                             By:
                                      ----------------------------------------
                                      Name:
                                      Title:

               [AMENDED & RESTATED REGISTRATION RIGHTS AGREEMENT]

                                      -30-
<PAGE>

                             ROBERT WILLIAMSON

                             /s/ R. Williamson
                             -------------------------------------------------

               [AMENDED & RESTATED REGISTRATION RIGHTS AGREEMENT]
                                  -31-
<PAGE>

                             RONALD G. CRYSTAL, M.D.

                             /s/ Ronald Crystal
                             ----------------------------------------

               [AMENDED & RESTATED REGISTRATION RIGHTS AGREEMENT]

                                      -32-

<PAGE>

                             SCIOS, INC.

                             By:    /s/ John Newman
                                    --------------------------------------
                                    Name:
                                    Title:

               [AMENDED & RESTATED REGISTRATION RIGHTS AGREEMENT]

                                      -33-

<PAGE>

                             HIGHLAND CAPITAL PARTNERS IV LIMITED PARTNERSHIP

                             By:      Highland Management Partners IV, LLC
                                      Its General Partner

                             By:      /s/ Robert F. Higgins
                                      -----------------------------------------
                                      Name:
                                      Title:

                             HIGHLAND ENTREPRENEURS' FUND IV LIMITED PARTNERSHIP

                             By:      Highland Entrepreneurs' Fund IV, LLC,
                                      Its General Partner

                             By:      /s/ Robert F. Higgins
                                      -----------------------------------------
                                      Name:
                                      Title:

               [AMENDED & RESTATED REGISTRATION RIGHTS AGREEMENT]

                                      -34-

<PAGE>

                             NEAL DELUCA

                             /s/ Neal Deluca
                             ----------------------------------------

               [AMENDED & RESTATED REGISTRATION RIGHTS AGREEMENT]

                                      -35-

<PAGE>

                                   SCHEDULE 1
                                   ----------

         Arch Venture Fund Limited Partnership
         Arch Venture Fund II, L.P.
         Genentech, Inc.
         Hillman Medical Ventures 1992, L.P.
         Hillman Medical Ventures 1993, L.P.
         Prince Venture Partners III, L.P.
         Sierra Ventures IV, L.P.
         Sierra Ventures International IV, L.P.

                                      -36-

<PAGE>

                                   SCHEDULE 2
                                   ----------

         Arch Venture Fund Limited Partnership
         Arch Venture Fund II, L.P.

                                      -37-

<PAGE>

                                   SCHEDULE 3
                                   ----------

         Edward Benz
         Wesley Church
         Martin P. Cleary
         Herbert J. Conrad
         Neal DeLuca
         Enterprise Development Fund Limited Partnership
         Christopher Evans
         David J. Fink
         Joseph C. Glorosio, III
         Leaf Huang
         Katherine B. Kaufman
         Wilma P. McCleve
         Paul Robbins
         Jerry W. Smith, Ph.D.
         Peter A. Ward
         Warner-Lambert Company
         Robert Williamson

                                      -38-

<PAGE>

                                   SCHEDULE 4
                                   ----------

         Difco, Inc.
         Enterprise Development Fund Limited Partnership
         Joel Schur
         Warner-Lambert Company

                                      -39-

<PAGE>

                                   SCHEDULE 5
                                   ----------

         Arch Venture Fund II, L.P.
         Enterprise Development Fund, L.P.
         Genentech, Inc.
         Hillman Medical Ventures 1994, L.P.
         Prince Venture Partners III, L.P.
         Sierra Ventures IV, L.P.
         Sierra Ventures International IV, L.P.

                                      -40-

<PAGE>

                                   SCHEDULE 6
                                   ----------

         Betty S. Bardige
         Biotech Growth SA
         Canaan Capital Limited Partnership
         Canaan Capital Offshore Limited Partnership, C.V.
         Canaan S.B.I.C., L.P.
         CIP Capital L.P.
         The CIT Group/Venture Capital, Inc.
         Fourth Generation Partners
         Mindful Partners, L.P.
         Prism Partners I, L.P.
         Quai Limited
         State of Michigan Retirement System
         Henry and Ruth Pear

                                      -41-

<PAGE>

                                   SCHEDULE 7
                                   ----------

         Highland Capital Partners IV Limited Partnership
         Highland Entrepreneurs' Fund IV Limited Partnership

                                      -42-

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