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                                                                     Exhibit 4.2

                                   GENVEC INC.

                            INVESTOR RIGHTS AGREEMENT

         THIS INVESTOR RIGHTS AGREEMENT (the "Agreement") is entered into as of
December 21, 2001, by and among GenVec Inc., a Delaware corporation (the
"Company"), and the holders of the Company's Common Stock set forth on Exhibit A
hereto. All of the holders of such shares of Common Stock shall be referred to
hereinafter as the "Investors" and each individually as an "Investor."


                                    RECITALS

                  WHEREAS, the Company proposes to sell and issue up to
3,582,000 shares of its Common Stock to the Investors;

         WHEREAS, as a condition of purchasing the shares of Common Stock, the
Investors have requested that the Company extend to them registration rights,
pre-emptive and other rights as set forth below;

         NOW, THEREFORE, in consideration of the mutual promises,
representations, warranties, covenants and conditions set forth in this
Agreement and the investment of the Investors in the Common Stock, the parties
mutually agree as follows:

SECTION 1. GENERAL

         1.1 Definitions. As used in this Agreement the following terms shall
have the following respective meanings:

                  "COMMON STOCK" means the Common Stock, $.001 par value of the
Company.

                  "EQUITY PERCENTAGE" shall mean, as to any Holder, that
percentage figure which expresses the ratio that (a) the number of shares of
issued and outstanding Common Stock then owned by such Holder bears to (b) the
aggregate number of shares of issued and outstanding Common Stock.

                  "EXCHANGE ACT" means the Securities Exchange Act of 1934, as
amended.

                  "FORM S-3" means such form under the Securities Act as in
effect on the date hereof or any successor registration form under the
Securities Act subsequently adopted by the SEC which permits inclusion or
incorporation of substantial information by reference to other documents filed
by the Company with the SEC.

                  "HCV V" means HealthCare Ventures V, LP.

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                  "HCV VI" means HealthCare Ventures VI, LP.

                  "HOLDER" means any person owning of record Registrable
Securities that have not been sold to the public or any assignee of record of
such Registrable Securities in accordance with Section 2.8 hereof.

                  "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
effectiveness of such registration statement or document.

                  "REGISTRABLE SECURITIES" means (a) the Shares and (b) any
Common Stock of the Company issued as (or issuable upon the conversion or
exercise of any warrant, right or other security which is issued as) a dividend
or other distribution with respect to, or in exchange for or in replacement of,
such above described securities. Notwithstanding the foregoing, Registrable
Securities shall not include as to any Holder, any securities (i) sold by a
person to the public pursuant to a registration statement or Rule 144 under the
Securities Act, (ii) eligible to be sold by a particular Holder under Rule
144(k) under the Securities Act or (iii) sold in a private transaction in which
the transferor's rights under Section 2 of this Agreement are not assigned.

                  "REGISTRABLE SECURITIES THEN OUTSTANDING" shall be the number
of shares determined by calculating the total number of shares of the Company's
Common Stock that are Registrable Securities and either (a) are then issued and
outstanding or (b) are issuable pursuant to then exercisable or convertible
securities.

                  "REGISTRATION EXPENSES" shall mean all expenses incurred by
the Company in complying with Sections 2.2 and 2.3 hereof, including, without
limitation, all registration and filing fees, printing expenses, fees and
disbursements of counsel for the Company, reasonable fees and disbursements not
to exceed an aggregate of $20,000 of a single special counsel for the Holders,
blue sky fees and expenses and the fees and expenses of all independent
accountants retained by the Company (but excluding the compensation of regular
employees of the Company which shall be paid in any event by the Company).

                  "SEC" or "COMMISSION" means the Securities and Exchange
Commission.

                  "SECURITIES ACT" shall mean the Securities Act of 1933, as
amended.

                  "SELLING EXPENSES" shall mean all underwriting fees, discounts
and selling commissions applicable to the sale.

                  "SHARES" shall mean the Company's Common Stock issued to the
Investors listed on Exhibit A hereto and their permitted assigns.

SECTION 2. REGISTRATION; RESTRICTIONS ON TRANSFER

         2.1 RESTRICTIONS ON TRANSFER.

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                  (a) Each Holder agrees not to make any disposition of all or
any portion of the Shares or Registrable Securities unless and until:

                           (i) There is then in effect a registration statement
under the Securities Act covering such proposed disposition and such disposition
is made in accordance with such registration statement;

                           (ii) Such disposition is made pursuant to and in
compliance with Rule 144; or

                           (iii) (A) The transferee has agreed in writing to be
bound by the terms of this Agreement by executing a counterpart signature page
hereto (which shall not be deemed to be an amendment hereto), (B) such Holder
shall have notified the Company of the proposed disposition and shall have
furnished the Company with a detailed statement of the circumstances surrounding
the proposed disposition, and (C) if reasonably requested by the Company, such
Holder shall have furnished the Company with an opinion of counsel, reasonably
satisfactory to the Company, that such disposition will not require registration
of such shares under the Securities Act.

                           (iv) Notwithstanding the provisions of paragraphs
(i), (ii) and (iii) above, no such registration statement or opinion of counsel
shall be necessary for a transfer by a Holder which is: (A) a Holder's transfer
without consideration of any or all Shares held either during such Holder's
lifetime or on death by will or intestacy to such Holder's immediate family or
to any custodian or trustee for the account of such Holder or such Holder's
immediate family. "Immediate family" as used herein shall mean spouse, lineal
descendant, father, mother, brother, or sister of the Holder making such
transfer; (B) a Holder's transfer of any or all of such Holder's Shares to the
Company; (C) a corporate Holder's transfer of any or all of its Shares pursuant
to and in accordance with the terms of any merger, consolidation,
reclassification of shares or capital reorganization of the corporate Holder, or
pursuant to a sale of all or substantially all of the stock or assets of a
corporate Holder; (D) a corporate Holder's transfer without consideration of any
or all of its Shares to any or all of its stockholders; (E) a transfer by a
Holder which is a limited or general partnership to any or all of its partners
or former partners; (F) a transfer without consideration by a limited liability
company to its members or former members in accordance with their interest in
the limited liability company; and (G) a transfer without consideration by a
Holder to a retirement plan (regardless of form) created by a Holder for the
primary benefit of, or in trust for, the Holder and/or such Holder's immediate
family or a transfer from such retirement plan to the designated beneficiary or
beneficiaries thereof; PROVIDED that in each case the transferee has agreed in
writing to be bound by the terms of this Agreement by executing a counterpart
signature page hereto (which shall not be deemed to be an amendment hereto).

                  (b) Each certificate representing Shares or Registrable
Securities shall (unless otherwise permitted by the provisions of the Agreement)
be stamped or otherwise imprinted with a legend substantially similar to the
following (in addition to any legend required under applicable state securities
laws):

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                  THE SECURITIES REPRESENTED HEREBY HAVE NOT BEEN REGISTERED
                  UNDER THE SECURITIES ACT OF 1933 (THE "ACT") AND MAY NOT BE
                  OFFERED, SOLD OR OTHERWISE TRANSFERRED, ASSIGNED, PLEDGED OR
                  HYPOTHECATED UNLESS AND UNTIL REGISTERED UNDER THE ACT OR
                  UNLESS THE COMPANY HAS RECEIVED AN OPINION OF COUNSEL OR OTHER
                  EVIDENCE SATISFACTORY TO THE COMPANY AND ITS COUNSEL THAT SUCH
                  REGISTRATION IS NOT REQUIRED.

                  (c) The Company shall be obligated to reissue promptly
unlegended certificates at the request of any Holder thereof if the Holder shall
have obtained an opinion of counsel (which counsel may be counsel to the
Company) reasonably acceptable to the Company to the effect that the securities
proposed to be unlegended may lawfully be so disposed of without registration,
qualification or legend.

                  (d) Any legend endorsed on an instrument pursuant to
applicable state securities laws and the stop transfer instructions with respect
to such securities shall be removed upon receipt by the Company of an order of
the appropriate blue sky authority authorizing such removal.

                  (e) Notwithstanding the foregoing provisions of this Section
2.1, the restrictions imposed by this Section 2.1 upon the transferability of
any Restricted Securities shall cease and terminate when (a) any such Restricted
Securities are sold or otherwise disposed of in accordance with the intended
method of disposition by the seller or sellers thereof set forth in a
registration statement or such other method contemplated by Section 2.1 hereof
that does not require that the securities transferred bear the legend set forth
in Section 2.1(b) hereof, including a transfer pursuant to Rule 144 under the
Securities Act or a successor rule thereof (as amended from time to time), or
(b) the holder of Restricted Securities has met the requirements for transfer of
such Restricted Securities pursuant to subparagraph (k) of Rule 144 under the
Securities Act or a successor rule thereof (as amended from time to time)
promulgated by the Commission under the Securities Act. Whenever the
restrictions imposed by this Section 2.1 have terminated, a holder of a
certificate for Restricted Securities as to which such restrictions have
terminated shall be entitled to receive from the Company, without expense, a new
certificate not bearing the restrictive legend set forth in Section 2.1(b)
hereof and not containing any other reference to the restrictions imposed by
this Section 2.1.

                  (f) During the period beginning 30 days prior to the date of
this Agreement and ending on the date of this Agreement, each Investor
represents, warrants, covenants and agrees that neither it, nor any persons
acting under its direction or control, has engaged, directly or indirectly, in
any trading of Common Stock, including but not limited to short sales (as
defined in any applicable SEC or NASD rules) or hedging of any kind, other than
as contemplated by the Stock Purchase Agreement entered into by and among the
Company and the Investors dated as of the date hereof (the "Stock Purchase
Agreement"). Further, each Investor agrees that it will not, and that it will
cause any persons acting under its direction or control not to, directly or
indirectly, engage in any short sales of or hedging transactions, in violation
of


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applicable SEC or NASD rules, with respect to the Company's Common Stock while
such Investor or person acting under its direction or control holds any of the
Shares.

         2.2 SHELF REGISTRATION. The Company shall within thirty (30) days from
the date of this Agreement (the "Filing Date") file a registration statement
under the Securities Act covering all of the Registrable Securities then
outstanding for an offering to be made on a continuous basis pursuant to Rule
415 in accordance with the intended method of distribution of the Holders (the
"Shelf Registration"). The Company shall use its reasonable best efforts to
effect, as soon as practicable, the registration of all Registrable Securities
to be registered and shall use its reasonable best efforts to cause the Shelf
Registration to become effective within 90 days of the Filing Date (the
"Required Effectiveness Date").

         2.3 PIGGYBACK REGISTRATIONS. The Company shall notify all Holders at
least 15 days prior to the filing of any registration statement under the
Securities Act covering the sale of securities of the Company for cash
(including, but not limited to, registration statements relating to secondary
offerings of securities of the Company, but excluding registration statements
relating to employee benefit plans or corporate reorganizations or other
transactions under Rule 145 of the Securities Act) and will afford each such
Holder an opportunity to include in such registration statement all or part of
the Registrable Securities held by such Holder. Each Holder desiring to include
Registrable Securities in any such registration statement shall notify the
Company within 5 days after the notice from the Company. Such notice shall state
the intended method of disposition of the Registrable Securities by such Holder.
If a Holder decides not to include all of its Registrable Securities in any
registration statement filed by the Company, such Holder shall nevertheless
continue to have the right to include any Registrable Securities in any
subsequent registration statement or registration statements as may be filed by
the Company, all upon the terms and conditions set forth herein.

                  (a) UNDERWRITING ARRANGEMENTS. The right of any Holder to
registration pursuant to this Section 2.3 in connection with an underwritten
offering shall be conditioned upon the participation by such Holder in the
underwriting arrangements specified by the Company in connection with such
registration and the inclusion of the Registrable Securities of such Holder in
such underwriting to the extent provided herein. All Holders proposing to
distribute their Registrable Securities through such underwriting shall
(together with the Company) enter into an underwriting agreement in customary
form with the managing underwriter; PROVIDED, HOWEVER, that none of the Holders
shall be required to make any representations or warranties or provide
indemnification except as it relates to such Holder's Registrable Securities,
including such Holder's ownership of Shares and authority to enter into the
underwriting agreement and to such Holder's intended method of distribution, and
the liability of such Holder shall be limited to an amount equal to the net
proceeds from the offering received by such Holder, except in the case of fraud.
Notwithstanding any other provision of this Section 2.3, if the managing
underwriter determines in good faith that marketing factors require a limitation
of the number of shares to be underwritten the managing underwriter may limit
the total number of Registrable Securities to be included in such registration
to the extent set forth below. The Company shall so advise all Holders
distributing Registrable Securities through such underwriting, and there shall
be included in such registration and underwriting, first shares offered by the
Company, then shares offered by any existing stockholder of the Company having


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registration rights senior to the Holders as of the date of this Agreement and
thereafter Shares offered by the Holders on a pro-rata basis.

                  (b) RIGHT TO TERMINATE REGISTRATION. The Company shall have
the right to terminate or withdraw any registration initiated by it under this
Section 2.3 prior to the effectiveness of such registration whether or not any
Holder has elected to include securities in such registration. The Registration
Expenses of such withdrawn registration shall be borne by the Company in
accordance with Section 2.4 hereof.

         2.4 EXPENSES OF REGISTRATION. Except as specifically provided herein,
all Registration Expenses incurred in connection with any registration,
qualification or compliance pursuant to Section 2.2 or any registration under
Section 2.3 herein shall be borne by the Company. All Selling Expenses incurred
in connection with any registrations hereunder, shall be borne by the Company or
the stockholders selling the securities, as the case may be.

         2.5 OBLIGATIONS OF THE COMPANY. Whenever required to register any
Registrable Securities, the Company shall, as expeditiously as reasonably
possible:

                  (a) Prepare and file with the SEC a registration statement
with respect to such Registrable Securities and use its reasonable best efforts
to cause such registration statement to become effective, and, in the case of
the Shelf Registration, keep such registration statement effective until the
earlier of 24 months or until such time that each Holder may dispose of all
Registrable Securities owned by such Holder without limitations as to volume or
method of sale (the "Effectiveness Period").

                           (i) Notwithstanding the above, the Company may
suspend the effectiveness of the Shelf Registration, suspend the use of any
prospectus included therein ("Prospectus") and shall not be required to amend or
supplement the Shelf Registration, any related Prospectus or any document
incorporated therein by reference for a period of time not to exceed 60
consecutive days and in no event to exceed more than an aggregate of 90 days
during any 12-month period (the "Pending Event Suspension Period"), if an event
or circumstance occurs and is continuing that (A) has not been publicly
disclosed and, if not disclosed in the Shelf Registration, any related
Prospectus or any document incorporated therein by reference as then amended or
supplemented would, in the Company's good faith reasonable judgment, result in
the Shelf Registration, any related Prospectus or any such document containing
an untrue statement of a material fact or omitting to state a material fact
required to be stated therein, or necessary in order to make the statements
therein, in the light of the circumstances under which they were made, not
misleading, and (B) in the good faith judgment of the Board of Directors of the
Company (the "Board"), after consultation with its outside securities counsel,
the Company has a bona fide business purpose for not then disclosing the
existence of such event or circumstance; provided, further, that the
Effectiveness Period shall be extended by the number of days in any Pending
Event Suspension Period occurring during the Effectiveness Period, and such
period and any extension thereof is hereinafter referred to as the
"Effectiveness Period."

         In the event of the occurrence of any Pending Event Suspension Period,
the Company will promptly notify the Holders in writing. The Company will also
provide written notice to the Holders of the end of each Pending Event
Suspension Period. Each Holder agrees to cease all

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public disposition efforts under any registration statement with respect to the
Common Stock held by such Holder immediately upon receipt of notice of the
beginning of any Pending Event Suspension Period and until the Holder receives
notice of the end of such Pending Event Suspension Period.

                           (ii) Upon the occurrence of any Event (as defined
below), as relief for the damages suffered therefrom by the Investors, the
Company shall pay to each Holder, such amounts and at such times as shall be
determined pursuant to this Section 2.5(a)(ii). For such purposes, each of the
following shall constitute an "Event":

                                    (A) the Shelf Registration is not filed in
appropriate form on or prior to the Filing Date, in which case the Company shall
pay (x) on the calendar day following the Filing Date an amount in cash equal to
one-half of one percent (0.5%) of the aggregate purchase price paid by such
Investor, plus (y) on the calendar day following every 30-calendar day period
following the Filing Date beginning with the 31st calendar day after the Filing
Date an amount in cash equal to one percent (1.0%) of the aggregate purchase
price paid by such Investor, provided that no such amounts shall be required to
be paid by the Company after the cure of such Event;

                                    (B) the Shelf Registration is not declared
effective on or prior to the Required Effectiveness Date, in which case the
Company shall pay (x) on the calendar day following the Required Effectiveness
Date an amount in cash equal to one-half of one percent (0.5%) of the aggregate
purchase price paid by such Investor, plus (y) on the calendar day following
every 30-calendar day period beginning with the 31st calendar day after the
Required Effectiveness Date an amount in cash equal to one percent (1.0%) of the
aggregate purchase price paid by such Investor, provided that no such amounts
shall be required to be paid by the Company after the cure of such Event; or

                                    (C) the Shelf Registration is declared
effective but thereafter, except pursuant to an allowable Pending Event
Suspension Period in compliance with Section 2.5(a)(i) hereof, ceases to be
effective or usable for any period of five consecutive trading days (an
"Effectiveness Default"), in which case the Company shall pay (x) on the
calendar day following the date of the Effectiveness Default an amount in cash
equal to one-half of one percent (0.5%) of the aggregate purchase price paid by
such Investor, plus (y) on the calendar day following every 30-calendar day
period following the Effectiveness Default beginning with the 31st calendar day
after the Effectiveness Default an amount in cash equal to one percent (1.0%) of
the aggregate purchase price paid by such Investor, provided that no such
amounts shall be required to be paid by the Company after the cure of such
Event.

                  (b) Prepare and file with the SEC such amendments and
supplements to such registration statement and the prospectus used in connection
with such registration statement 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 for the period set forth in
paragraph (a) above including such amendments as may be necessary for the
Holders to sell their Registrable Shares in an underwritten offering.

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                  (c) Furnish to the Holders such number of copies of a
prospectus, including a preliminary prospectus, in conformity with the
requirements of the Securities Act, and such other documents as they may
reasonably request in order to facilitate the disposition of Registrable
Securities owned by them.

                  (d) Use its reasonable best efforts to register or qualify the
securities covered by such registration statement under such other securities or
Blue Sky laws of such jurisdictions in the United States of America 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, subject itself to taxation, register as a broker or dealer in
securities or file a general consent to service of process in any such states or
jurisdictions.

                  (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(s) of such offering and otherwise
cooperate with the Holders as requested in connection with such offering,
including, without limitation, causing its President and Chief Executive Officer
and Chief Financial Officer to participate in a "road show" in connection with
such underwritten offering.

                  (f) Notify each Holder of Registrable Securities covered by
such registration statement at any time when a prospectus relating thereto is
required to be delivered under the Securities Act of the happening of any event
as a result of which the prospectus included in such registration statement, as
then in effect, includes an untrue statement of a material fact or omits to
state a material fact required to be stated therein or necessary to make the
statements therein not misleading in the light of the circumstances then
existing. Each Investor agrees to cease all public disposition efforts under any
registration statement with respect to the Common Stock held by such Investor
immediately upon receipt of such notice and until the Investor receives notice
that such deficiency has been cured.

                  (g) Request that (i) counsel representing the Company for the
purposes of such registration furnish to the Holders, on the date that such
Registrable Securities are delivered to the underwriters for sale, if such
securities are being sold through underwriters, an opinion, dated as of such
date, in form and substance as is customarily given to underwriters in an
underwritten public offering, addressed to the underwriters, if any, and (ii)
the Company's auditors furnish to the Holders, a letter dated as of such date,
in form and substance as is customarily given by independent certified public
accountants to underwriters in an underwritten public offering addressed to the
underwriters.

                  (h) Cause the Registrable Securities to be listed or included
on each securities exchange on which similar securities are then listed or
included.

                  (i) Following the effective date of the Shelf Registration,
issue to transferees of the Holders which are limited partners of the Holders,
certificates representing the Shares that will be free of any restrictive
legends if, and to the extent, such transferees execute a representation letter
reasonably acceptable to the Company with respect to compliance with federal and
state securities laws.

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         2.6 FURNISHING INFORMATION. It shall be a condition precedent to the
obligations of the Company to take any action pursuant to Section 2.2 or 2.3
that the selling Holders shall furnish to the Company such information regarding
themselves, the Registrable Securities held by them and the intended method of
disposition of such securities and such other information as shall be required
to effect the registration of their Registrable Securities.

         2.7 INDEMNIFICATION. In the event any Registrable Securities are
included in a registration statement under Sections 2.2 or 2.3:

                  (a) To the extent permitted by law, the Company will indemnify
and hold harmless each Holder and the partners, officers, directors and
stockholders of each Holder, any underwriter (as defined in the Securities Act)
for such Holder and each person, if any, who controls such Holder or underwriter
within the meaning of the Securities Act or the Exchange Act, against any
losses, claims, damages, or liabilities (joint or several) to which they may
become subject under the Securities Act, the Exchange Act or other federal or
state law, insofar as such losses, claims, damages or liabilities (or actions in
respect thereof) arise out of or are based upon any of the following statements,
omissions or violations (collectively a "Violation") by the Company: (i) any
untrue statement or alleged untrue statement of a material fact contained in
such registration statement, including any preliminary prospectus or final
prospectus contained therein or any amendments or supplements thereto, (ii) the
omission or alleged omission to state therein a material fact required to be
stated therein, or necessary to make the statements therein not misleading, or
(iii) any violation or alleged violation by the Company of the Securities Act,
the Exchange Act, any state securities law or any rule or regulation promulgated
under the Securities Act, the Exchange Act or any state securities law in
connection with the offering covered by such registration statement; and the
Company will pay as incurred to each such Holder, partner, officer, director,
stockholder, underwriter or controlling person for any legal or other expenses
reasonably incurred by them in connection with investigating or defending any
such loss, claim, damage, liability or action (subject to recoupment if this
indemnification is determined to be inapplicable); provided however, that the
indemnity agreement contained in this Section 2.7(a) shall not apply to amounts
paid in settlement of any such loss, claim, damage, liability or action if such
settlement is effected without the consent of the Company, which consent shall
not be unreasonably withheld, nor shall the Company be liable in any such case
for any such loss, claim, damage, liability or action to the extent that it
arises out of or is based upon a Violation which occurs (i) in reliance upon and
in conformity with written information furnished expressly for use in connection
with such registration by such Holder, partner, officer, director, stockholder,
underwriter or controlling person of such Holder or (ii) pursuant to such
Holder's use of an outdated or defective prospectus after the Company has
notified such Holder that the prospectus is outdated or defective.

                  (b) To the extent permitted by law, 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,
severally and not jointly, indemnify and hold harmless the Company, each of its
directors, officers, agents, employees and its legal counsel and independent
accountants, and each person, if any, who controls the Company within the
meaning of the Securities Act, any underwriter and any other Holder selling
securities under such registration statement or any of such other Holder's
partners, directors, officers, agents, employees,


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stockholders, legal counsel and independent accountants, or any person who
controls such Holder, against any losses, claims, damages or liabilities to
which the Company or any such person may become subject under the Securities
Act, the Exchange Act or other federal or state law, insofar as such losses,
claims, damages or liabilities (or actions in respect thereto) arise out of or
are based upon any Violation, in each case to the extent (and only to the
extent) that such Violation occurs in reliance upon and in conformity with
written information furnished by such Holder under an instrument duly executed
by such Holder and stated to be specifically for use in connection with such
registration statement; and each such Holder will pay as incurred any legal or
other expenses reasonably incurred by the Company or any such person in
connection with investigating or defending any such loss, claim, damage,
liability or action if it is judicially determined that there was such a
Violation; PROVIDED, HOWEVER, that the indemnity agreement contained in this
Section 2.7(b) shall not apply to amounts paid in settlement of any such loss,
claim, damage, liability or action if such settlement is effected without the
consent of the Holder, which consent shall not be unreasonably withheld;
provided further, that in no event shall any indemnity under this Section 2.7(b)
exceed the net proceeds from the offering received by such Holder.

                  (c) Promptly after receipt by an indemnified party under this
Section 2.7 of notice of the commencement of any action (including any
governmental action), such indemnified party will, if a claim in respect thereof
is to be made against any indemnifying party under this Section 2.7, deliver to
the indemnifying party a written notice of the commencement thereof and the
indemnifying party shall have the right to participate in, and, to the extent
the indemnifying party so desires, jointly with any other indemnifying party
similarly noticed, to assume the defense thereof with counsel mutually
satisfactory to the parties; PROVIDED, HOWEVER, that an indemnified party shall
have the right to retain its own counsel, if such indemnified party shall have
been advised by counsel that representation of such indemnified party by the
counsel retained by the indemnifying party would be inappropriate due to actual
or potential differing interests between such indemnified party and any other
party represented by such counsel in such proceeding; PROVIDED FURTHER, HOWEVER,
that the indemnifying party shall not be responsible for the fees and expenses
of more than one counsel for all indemnified parties. The failure to deliver
written notice to the indemnifying party within a reasonable time of the
commencement of any such action, if materially prejudicial to its ability to
defend such action, shall relieve such indemnifying party of any liability to
the indemnified party under this Section 2.7, but the omission so to deliver
written notice to the indemnifying party will not relieve it of any liability
that it may have to any indemnified party otherwise than under this Section 2.7.

                  (d) If the indemnification provided for in this Section 2.7 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 Violation(s) 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, whether the untrue or alleged


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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 net proceeds
from the offering received by such Holder.

                  (e) The obligations of the Company and Holders under this
Section 2.7 shall survive completion of any offering of Registrable Securities
in a registration statement and the termination of this Agreement. 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.

         2.8 ASSIGNMENT OF REGISTRATION RIGHTS. The rights to cause the Company
to register Registrable Securities and to provide indemnification pursuant to
this Section 2 may be assigned by a Holder to a transferee or assignee of
Registrable Securities which (a) is a subsidiary, parent, general partner,
limited partner, retired partner, member, retired member or affiliate of a
Holder, (b) is a Holder's immediate family member or trust for the benefit of an
individual Holder or immediate family members or (c) acquires at least 50,000
shares of Registrable Securities (as adjusted for stock splits, combinations and
similar events); PROVIDED, HOWEVER, (i) the transferor shall, within ten (10)
days after such transfer, furnish to the Company written notice of the name and
address of such transferee or assignee and the securities with respect to which
such registration rights are being assigned and (ii) such transferee shall agree
to be subject to all restrictions set forth in this Agreement by executing a
counterpart signature page hereto (which shall not be deemed to be an amendment
hereto).

         2.9 AMENDMENT OF REGISTRATION RIGHTS. Any provision of this Section 2
may be amended and the observance thereof may be waived (either generally or in
a particular instance and either retroactively or prospectively), only with the
written consent of the Company and the Holders of at least a majority of the
Registrable Securities then outstanding. Any amendment or waiver effected in
accordance with this Section 2.9 shall be binding upon each Holder and the
Company. By acceptance of any benefits under this Section 2, Holders of
Registrable Securities hereby agree to be bound by the provisions hereunder.

         2.10 LIMITATION ON SUBSEQUENT REGISTRATION RIGHTS. After the date of
this Agreement, the Company shall not, without the prior written consent of the
Holders of a majority of the Registrable Securities then outstanding, enter into
any agreement with any holder or prospective holder of any securities of the
Company that would grant such holder registration rights senior to those granted
to the Holders hereunder.

         2.11 RULE 144 REPORTING. With a view to making available to the Holders
the benefits of certain rules and regulations of the SEC which may permit the
sale of the Registrable Securities to the public without registration, the
Company agrees to use its reasonable best efforts to:


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                  (a) Make and keep public information available, as those terms
are understood and defined in SEC Rule 144 or any similar or analogous rule
promulgated under the Securities Act;

                  (b) File with the SEC, in a timely manner, all reports and
other documents required of the Company under the Exchange Act; and

                  (c) So long as a Holder owns any Registrable Securities,
furnish to such Holder forthwith upon request: a written statement by the
Company as to its compliance with the reporting requirements of said Rule 144 of
the Securities Act, and of the Exchange Act; a copy of the most recent annual or
quarterly report of the Company; and such other reports and documents as a
Holder may reasonably request in availing itself of any rule or regulation of
the SEC allowing it to sell any such securities without registration.

SECTION 3 COVENANTS OF THE COMPANY

         3.1 INSPECTION RIGHTS. Each Holder shall have the right to visit and
inspect any of the properties of the Company or any of its subsidiaries, and to
discuss the affairs, finances and accounts of the Company or any of its
subsidiaries with its officers, and to review such information as is reasonably
requested all during normal business hours following reasonable notice and as
often as may be reasonably requested; PROVIDED, HOWEVER, that the Company shall
not be obligated under this Section 3.1 with respect to any Holder that is a
competitor of the Company.

         3.2 CONFIDENTIALITY OF RECORDS. Each Holder agrees to use, and to use
its reasonable best efforts to insure that its authorized representatives use,
the same degree of care as such Holder uses to protect its own confidential
information to keep confidential any information furnished to it which the
Company identifies in writing as being confidential or proprietary (so long as
such information is not in the public domain), except that such Holder may
disclose such proprietary or confidential information to any partner, subsidiary
or parent of such Holder for the purpose of evaluating its investment in the
Company as long as such partner, subsidiary or parent is advised of the
confidentiality provisions of this Section 3.2.

         3.3 BOARD OF DIRECTORS; COMMITTEES; BY-LAWS.

                  (a) VOTING FOR DIRECTORS. Effective January 1, 2002, the Board
of Directors of the Company, subject to its fiduciary duties, shall elect the
Investors' designee to fill a vacancy in a class of directors of the Board in
accordance with the provisions of the Company's by-laws. During the remaining
term of this Agreement, at each annual meeting of the stockholders of the
Company and at each special meeting of the stockholders of the Company called
for the purposes of electing directors of the class in which the director
elected pursuant to this Section 3.3(a) is included, and at any time at which
stockholders of the Company shall have the right to, or shall, vote for or
consent to the election of such class of directors, then the Company shall
nominate for election and the Board shall so support in connection with the
election thereto one

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<Page>

(1) director designated by the Investors who is reasonably satisfactory to the
Company. The Company shall use its reasonable best efforts to effectuate the
purposes of this Section 3.3.

                  (b) NOTICES. The Investors shall notify the Company in writing
of the persons designated by it pursuant to Section 3.3(a) above as nominee for
election to the Board, and shall promptly furnish all information necessary for
all required filings with the SEC. In the absence of any notice from the
Investors, the director then serving and previously designated by the Investors
shall be renominated.

                  (c) VACANCY. Any vacancy on the Board created by the
resignation, removal, incapacity or death of any person designated under the
foregoing provisions of this Section 3.3 shall be filled by another person
designated by the Investors. Each member of the Board shall vote in accordance
with each such new designation, and no such vacancy shall be filled in the
absence of a new designation by the original Designating Party.

         3.4 DIRECTORS' EXPENSES. The Director elected pursuant to Section 3.3
hereof shall be entitled to compensation, reimbursement for reasonable out of
pocket expenses incurred in connection with the performance of his or her duties
as a Director, Directors' liability insurance and indemnification in accordance
with the policies established by the Board for all Directors generally.

         3.5 INDEMNIFICATION WITH RESPECT TO HOLDERS; ADVANCEMENT. In the event
that either of HCV V, HCV VI, or any director, officer, employee, affiliate or
agent thereof (the "Indemnitees"), becomes involved in any action, proceeding,
investigation or inquiry in connection with or arising out of any matter by
virtue of the service of any Indemnitee as a director of the Company, the
Company shall, to the extent legally permissible, reimburse each Indemnitee for
its legal and other expenses (including the cost of any investigation and
preparation) as they are incurred by such Indemnitee in connection therewith,
and all liabilities, damages, losses, settlements, claims, actions, suits,
penalties, fines, costs or expenses (including, without limitation, attorneys'
fees), incurred by or asserted against any Indemnittee of whatever kind or
nature, on terms no less favorable than those provided to any similarly situated
director of the Company. The foregoing agreement shall be in addition to any
rights that any Indemnitee may have at common law or otherwise.

SECTION 4 PRE-EMPTIVE RIGHTS

         4.1 SUBSEQUENT OFFERINGS. Each Holder shall have the pre-emptive right
to purchase its Equity Percentage of all Equity Securities, as defined below,
that the Company may, from time to time, propose to sell and issue after the
date of this Agreement, other than the Equity Securities excluded by Section 4.5
hereof. The term "Equity Securities" shall mean (i) any Common Stock or
Preferred Stock of the Company, (ii) any security convertible, with or without
consideration, into any Common Stock or Preferred Stock (including any option to
purchase such a convertible security), (iii) any security carrying any warrant
or right to subscribe to or purchase any Common Stock or Preferred Stock or (iv)
any such warrant or right.

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<Page>

         4.2 EXERCISE OF RIGHTS. If the Company proposes to issue any Equity
Securities, it shall give the Holders notice of its intention, describing the
Equity Securities, the price and the terms and conditions upon which the Company
proposes to issue the same. Each Holder shall have 20 days from the giving of
such notice to agree to purchase up to its Equity Percentage of the Equity
Securities for the price and upon the terms and conditions specified in the
notice by giving notice to the Company and stating therein the quantity of
Equity Securities it agrees to purchase. If some but not all of the Holders
elect to purchase their Equity Percentage of the offered Equity Securities,
those electing Holders shall have five additional days to agree to purchase all
but not less than all of the offered Equity Securities that were available for
purchase by the non-electing Holders, allocated pro rata among the electing
Holders who choose to purchase such additional offered Equity Securities.
Notwithstanding the above, if the pre-emptive rights hereunder are exercised by
HCV V or HCV VI in connection with a firm commitment underwritten public
offering, HCV V and HCV VI shall, if requested, comply with reasonable
conditions and procedures imposed by the managing underwriters thereof and
otherwise with applicable rules and regulations.

         4.3 NO TERMINATION UPON WAIVER OF PRE-EMPTIVE RIGHTS. The pre-emptive
rights established by this Section 4 shall not terminate nor be deemed to be
waived with respect to any subsequent transactions if the Holders and/or their
assignees do not exercise their rights as provided in Section 4.2 to purchase
Equity Securities offered to them pursuant to Section 4.1. The provisions of
this Section 4 may be amended or waived only by the agreement of the Company and
the holders of at least a majority of the shares of Common Stock purchased by
the Investors.

         4.4 TRANSFER OF PRE-EMPTIVE RIGHTS. Each Holder may assign its
pre-emptive rights under this Section 4 in whole or in part to one or more of
the following: any subsidiary, parent, general partner, limited partner, retired
partner, member, retired member, general partner of a general partner, affiliate
or family trust of such Holder, who shall agree to be bound by this Agreement in
connection with and following such assignment by executing a counterpart
signature page hereto (which shall not be deemed to be an amendment hereto).

         4.5 EXCLUDED SECURITIES. The pre-emptive rights established by this
Section 4 shall have no application to any of the following Equity Securities:

                  (a) shares of Common Stock (and/or options, warrants or other
Common Stock purchase rights issued pursuant to such options, warrants or other
rights) issued or to be issued to employees, officers or directors of, or
consultants or advisors to the Company or any subsidiary, pursuant to
compensation plans, agreements, or other arrangements that are approved by the
Board of Directors;

                  (b) as to Holders other than HCV V and HCV VI, shares of
Common Stock issued in connection with a firm commitment underwritten public
offering;

                  (c) any Equity Securities issued pursuant to such rights or
agreements granted after the date of this Agreement, PROVIDED that the
pre-emptive rights established by this Section 4 applied with respect to the
initial sale or grant by the Company of such rights or agreements;


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<Page>


                  (d) any Equity Securities issued for consideration other than
cash pursuant to a merger, consolidation, acquisition or similar business
combination;

                  (e) any Equity Securities issued in connection with any stock
split, stock dividend or recapitalization by the Company;

                  (f) any Equity Securities issued pursuant to any equipment
leasing arrangement, or debt financing from a bank or similar financial
institution; and

                  (g) any Equity Securities issued in connection with strategic
transactions involving the Company and other entities, including but not limited
to (i) joint ventures, manufacturing, marketing or distribution arrangements or
(ii) technology transfer or development arrangements.

SECTION 5 MISCELLANEOUS

         5.1 TERMINATION. The rights and obligations of the Company and the
Holders under this Agreement shall terminate as to any specific Holder at the
earlier of (i) such time that all Holders hereunder own, in the aggregate, less
than 50% of the total Shares purchased by the Investors and (ii) seven years
from the date hereof except that the provisions of Sections 2.7, 3.4 and 3.5
shall not terminate and shall extend until there is no representative, partner
or designee of HCV V or HCV VI on the Board of Directors of the Company.

         5.2 GOVERNING LAW. This Agreement shall be governed by and construed
under the laws of the State of Delaware as applied to agreements among Delaware
residents entered into and to be performed entirely within Delaware.

         5.3 SURVIVAL. Except as expressly provided herein, the representations,
warranties, covenants, and agreements made herein shall survive any
investigation made by any Holder and the closing of the transactions
contemplated hereby. All statements as to factual matters contained in any
certificate or other instrument delivered by or on behalf of the Company
pursuant hereto in connection with the transactions contemplated hereby shall be
deemed to be representations and warranties by the Company hereunder solely as
of the date of such certificate or instrument.

         5.4 FURTHER ASSURANCES. Each party to this Agreement agrees to act in
accordance herewith and not to take any action that is designed to avoid the
intention hereof. From time to time, as and when requested by any party hereto,
the other parties shall execute and deliver, or cause to be executed and
delivered, all such documents and instruments and shall take, or cause to be
taken, all such further or other actions as such party may reasonably deem
necessary or appropriate in connection with the consummation of the transactions
contemplated by this Agreement.

         5.5 SUCCESSORS AND ASSIGNS. Except as otherwise expressly 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 and shall inure to the benefit of and be


                                       15

<Page>

enforceable by each person who shall be a holder of Registrable Securities and
in particular any assignee, from time to time; PROVIDED, HOWEVER, that prior to
the receipt by the Company of adequate written notice of the transfer of any
Registrable Securities specifying the full name and address of the transferee,
the Company may deem and treat the person listed as the holder of such shares in
its records as the absolute owner and holder of such shares for all purposes,
including the payment of dividends or any redemption price.

         5.6 ENTIRE AGREEMENT. This Agreement, the Exhibits hereto, the Stock
Purchase Agreement and the other documents delivered pursuant thereto constitute
the full and entire understanding and agreement between the parties with regard
to the subjects hereof and no party shall be liable or bound to any other in any
manner by any representations, warranties, covenants and agreements except as
specifically set forth herein and therein.

         5.7 SEVERABILITY. In case any provision of the Agreement shall be
invalid, illegal, or unenforceable, the validity, legality, and enforceability
of the remaining provisions shall not in any way be affected or impaired
thereby.

         5.8  AMENDMENT AND WAIVER.

                  (a) Except as otherwise expressly provided, this Agreement may
be amended or modified only upon the consent of (i) the Company, and (ii) the
holders of at least a majority of the Shares.

                  (b) Except as otherwise expressly provided, the obligations of
the Company and the rights of the Holders under this Agreement may be waived
only with the consent of the holders of at least a majority of the Shares.

         5.9 DELAYS OR OMISSIONS. It is agreed that no delay or omission to
exercise any right, power, or remedy accruing to any Holder, upon any breach,
default or noncompliance of the Company under this Agreement shall impair any
such right, power, or remedy, to the extent that the Company is not prejudiced
thereby, nor shall it be construed to be a waiver of any such breach, default or
noncompliance, or any acquiescence therein, or of any similar breach, default or
noncompliance thereafter occurring. It is further agreed that any waiver,
permit, consent, or approval of any kind or character on any Holder's part of
any breach, default or noncompliance under the Agreement or any waiver on such
Holder's part 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, by law, or otherwise
afforded to Holders, shall be cumulative and not alternative.

         5.10 NOTICES AND CONSENTS. All notices and consents required or
permitted hereunder must be in writing and shall be deemed effectively given:
(a) upon personal delivery to the party to be notified, (b) when sent by
facsimile if sent during normal business hours of the recipient; if not, then on
the next business day, (c) five days after having been sent by registered or
certified mail, return receipt requested, postage prepaid, or (d) one business
day after deposit with a nationally recognized overnight courier, specifying
next day delivery, with written verification of receipt. All communications
shall be sent to the party to be notified at the address as set forth on


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<Page>

the signature pages hereof or Exhibit A hereto or at such other address as such
party may designate by ten (10) days advance written notice to the other parties
hereto.

         5.11 TITLES AND SUBTITLES. The titles of the sections and subsections
of this Agreement are for convenience of reference only and are not to be
considered in construing this Agreement.

         5.12 COUNTERPARTS. This Agreement may be executed in any number of
counterparts, each of which shall be an original, but all of which together
shall constitute one instrument.


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<Page>


         IN WITNESS WHEREOF, the parties hereto have executed this INVESTOR
RIGHTS AGREEMENT as of the date set forth in the first paragraph hereof.


                                  GENVEC, INC.

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


INVESTORS:


                                  HEALTHCARE VENTURES VI, L.P.

                                  By: HealthCare Partners VI, L.P.
                                         its General Partner


                                  By: /s/ Jeffrey B. Steinberg
                                     ------------------------------------------
                                      Jeffrey B. Steinberg
                                      Title: Administrative Partner


                                  HEALTHCARE VENTURES V, L.P.
                                  By: HealthCare Partners V, L.P.
                                        its General Partner

                                  By: /s/ Jeffrey B. Steinberg
                                     ------------------------------------------
                                     Jeffrey B. Steinberg
                                     Title: Administrative Partner

<Page>


                                    EXHIBIT A

INVESTORS

HEALTHCARE VENTURES VI, L.P.



HEALTHCARE VENTURES V, L.P.



                                       2