<PAGE>

                                                                     Exhibit 4.2


THIS WARRANT HAS NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS
AMENDED OR APPLICABLE STATE SECURITIES LAWS AND MAY NOT BE SOLD, OFFERED FOR
SALE, TRANSFERRED, PLEDGED OR OTHERWISE DISPOSED OF UNLESS IT HAS BEEN
REGISTERED UNDER THOSE LAWS OR UNLESS THE COMPANY HAS RECEIVED AN OPINION OF
COUNSEL SATISFACTORY TO IT THAT AN EXEMPTION FROM REGISTRATION UNDER EACH OF
THOSE LAWS IS AVAILABLE.

THIS WARRANT IS SUBJECT TO PARTIAL CANCELATION UNDER CERTAIN CIRCUMSTANCES SET
FORTH IN SECTION 9 HEREOF.

THIS WARRANT MAY NOT BE TRANSFERRED EXCEPT AS PROVIDED IN SECTION 24.

No. WA-                        Right to Purchase ______________ Shares of Common
                               Stock of Valentis, Inc.



                                 VALENTIS, INC.

                  FORM OF COMMON STOCK PURCHASE WARRANT, CLASS A

          VALENTIS, INC., a Delaware corporation (the "Company"), hereby
certifies that, for value received, [INSERT NAME OF HOLDER] or registered
assigns (the "Holder"), is entitled, subject to the terms set forth below, to
purchase from the Company at any time or from time to time on or after the
Issuance Date and before 5:00 p.m., New York City time, on the Expiration Date
(such capitalized term and all other capitalized terms used herein having the
respective meanings provided herein), _____ fully paid and nonassessable shares
of Common Stock at a purchase price per share equal to the Purchase Price. The
number of such shares of Common Stock and the Purchase Price are subject to
adjustment as provided in this Warrant.

          As used herein the following capitalized terms, unless the context
otherwise requires, have the following respective meanings:

          "Aggregate Purchase Price" means at any time an amount equal to the
     product obtained by multiplying (x) the Purchase Price TIMES (y) the number
     of shares of Common Stock for which this Warrant may be exercised at such
     time.

          "Applicable Portion" means the lesser of (x) the unexercised portion
     of this Warrant that is outstanding on the applicable date of cancellation
     pursuant to Section 9

<PAGE>

     and (y) the portion of this Warrant which entitles the Holder to purchase a
     number of shares of Common Stock (or other securities deliverable
     hereunder) equal to fifty percent (50%) of the aggregate number of Warrant
     Shares subject to this Warrant, determined without regard to any prior
     exercise hereof.

          "Average Market Price" means the arithmetic average of the Market
     Price during any period of ten (10) consecutive Trading Days.

          "Business Day" means any day other than a Saturday, Sunday or other
     day on which commercial banks in The City of New York are authorized or
     required by law to remain closed.

          "Cancelation Date" has the meaning provided in Section 9(b).

          "Certificate of Designations" shall have the meaning provided in the
     Subscription Agreement.

          "Common Stock" means the Common Stock, $.001 par value, of the
     Company, or any shares of capital stock of the Company into which such
     shares shall be changed or reclassified after the Issuance Date.

          "Common Stock Equivalents" means any warrant, option, subscription or
     purchase right with respect to shares of Common Stock, any security
     convertible into, exchangeable for, or otherwise entitling the holder
     thereof to acquire, shares of Common Stock or any warrant, option,
     subscription or purchase right with respect to any such convertible,
     exchangeable or other security.

          "Company" shall include Valentis, Inc., a Delaware corporation, and
     any corporation that shall succeed to or assume the obligations of
     Valentis, Inc. hereunder in accordance with the terms hereof.

          "Current Fair Market Value" means when used with respect to the Common
     Stock as of a specified date with respect to each share of Common Stock,
     the average of the closing prices of the Common Stock sold on all
     securities exchanges (including the Nasdaq and the Nasdaq SmallCap) on
     which the Common Stock may at the time be listed, or, if there have been no
     sales on any such exchange on such day, the average of the highest bid and
     lowest asked prices on all such exchanges at the end of such day, or, if on
     such day the Common Stock is not so listed, the average of the
     representative bid and asked prices quoted in the NASDAQ System as of 4:00
     p.m., New York City time, or, if on such day the Common Stock is not quoted
     in the NASDAQ System, the average of the highest bid and lowest asked price
     on such day in the domestic over-the-counter market as reported by the
     National Quotation Bureau, Incorporated, or any similar successor
     organization, in each such case averaged over a period of five Trading Days
     consisting of the day as of which the Current Fair Market Value of Common
     Stock is being determined (or if such day is not a Trading Day, the Trading
     Day next preceding such day) and the four consecutive Trading Days prior to
     such day. If on the date for which Current Fair Market Value is to be
     determined the Common Stock is not listed on any securities exchange or
     quoted in the NASDAQ System or the over-the-counter


                                       2
<PAGE>

     market, the Current Fair Market Value of Common Stock shall be the greater
     of (i) the highest price per share of Common Stock at which the Company has
     sold shares of Common Stock or Common Stock Equivalents within 365 days
     prior to the date of such determination and (ii) the highest price per
     share which the Company could then obtain from a willing buyer (not an
     employee or director of the Company at the time of determination) for
     shares of Common Stock sold by the Company, from authorized but unissued
     shares, as determined in good faith by the Board of Directors.

          "Expiration Date" means the fourth anniversary of the Issuance Date.

          "Issuance Date" means the date of original issuance of this Warrant.

          "Market Price" shall have the meaning provided in the Certificate of
     Designations.

          "Nasdaq" means the Nasdaq National Market.

          "Nasdaq SmallCap" means the Nasdaq SmallCap Market.

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

          "1933 Act" means the Securities Act of 1933, as amended.

          "Other Securities" means any stock (other than Common Stock) and other
     securities of the Company or any other Person which the Holder at any time
     shall be entitled to receive, or shall have received, on the exercise of
     this Warrant, in lieu of or in addition to Common Stock, or which at any
     time shall be issuable or shall have been issued in exchange for or in
     replacement of Common Stock or Other Securities pursuant to Section 4.

          "Other Subscription Agreements" means the several Subscription
     Agreements, dated as of the date of the Subscription Agreement, by and
     between the Company and the several buyers named therein.

          "Other Warrants" means the Warrants and the Class B Warrants issued on
     the Issuance Date pursuant to the Subscription Agreement and the Other
     Subscription Agreements.

          "Person" means an individual, partnership, corporation, limited
     liability company, trust or unincorporated organization, or a government or
     a governmental agency or political subdivision.

          "Purchase Price" means $10.25, subject to adjustment as provided in
     this Warrant.

          "QIB" means a "qualified institutional buyer" as defined in Rule 144A.

          "Registration Statement" shall have the meaning provided in the
     Subscription Agreement.


                                       3
<PAGE>

          "Reorganization Event" means the occurrence of any one or more of the
     following events:

          (i) any consolidation, merger or similar transaction of the Company or
     any Subsidiary with or into another entity (other than a merger or
     consolidation or similar transaction of a Subsidiary into the Company or a
     wholly-owned Subsidiary); or the sale or transfer of all or substantially
     all of the assets of the Company and the Subsidiaries in a single
     transaction or a series of related transactions; or

          (ii) the occurrence of any transaction or event in connection with
     which all or substantially all the Common Stock shall be exchanged for,
     converted into, acquired for or constitute the right to receive securities
     of any other Person (whether by means of an exchange offer, liquidation,
     tender offer, consolidation, merger, share exchange, combination,
     reclassification, recapitalization, or otherwise); or

          (iii) the acquisition by a Person or group of Persons acting in
     concert as a partnership, limited partnership, syndicate or group, as a
     result of a tender or exchange offer, open market purchases, privately
     negotiated purchases or otherwise, of beneficial ownership of securities of
     the Company representing 50% or more of the combined voting power of the
     outstanding voting securities of the Company ordinarily (and apart from
     rights accruing in special circumstances) having the right to vote in the
     election of directors.

          "Restricted Securities" means securities that are not eligible for
     resale pursuant to Rule 144(k) under the 1933 Act (or any successor
     provision).

          "Rule 144A" means Rule 144A as promulgated under the 1933 Act.

          "SEC" means the Securities and Exchange Commission.

          "Series A Preferred Stock" means the Series A Convertible Redeemable
     Preferred Stock, par value $0.001 per share, of the Company issued pursuant
     to the Subscription Agreement and the Other Subscription Agreements.

          "Subscription Agreement" means the Subscription Agreement, dated as of
     November __, 2000, by and between the Company and the original Holder of
     this Warrant.

          "Subsidiary" means any corporation or other entity of which a majority
     of the capital stock or other ownership interests having ordinary voting
     power to elect a majority of the board of directors or other persons
     performing similar functions are at the time directly or indirectly owned
     by the Company.

          "Target Price" means 275% of the Purchase Price.

          "Tender Offer" means a tender offer, exchange offer or other offer by
     the Company to repurchase outstanding shares of its capital stock.



                                       4
<PAGE>


          "Trading Day" means a day on which the national securities exchange,
     the Nasdaq or the Nasdaq SmallCap which then constitutes the principal
     securities market for the Common Stock is open for general trading.

          "Transaction Documents" shall have the meaning provided in the
     Subscription Agreement.

          "Warrant" means this Warrant and any Warrant or Warrants which may be
     issued pursuant to Section 4 or 5 hereof in substitution or exchange for or
     upon transfer of this Warrant, any Warrant which may be issued pursuant to
     Section 2 hereof upon partial exercise of this Warrant and any Warrant
     which may be issued pursuant to Section 6 hereof upon the loss, theft,
     destruction or mutilation of this Warrant.

          "Warrant Shares" means the shares of Common Stock, as adjusted from
     time to time in accordance with Section 8 hereof, deliverable upon exercise
     of this Warrant.

          1.        Exercise of Warrant.

          1.1       EXERCISE. This Warrant may be exercised by the Holder in
full or in part at any time or in part from time to time for four years starting
on the Issuance Date by (x) surrendering this Warrant to the Company, (y) giving
a subscription form in the form of Exhibit 1 to this Warrant (duly executed by
the Holder) to the Company, and (z) making payment, in cash or by certified or
official bank check payable to the order of the Company, or by wire transfer of
funds to the account of the Company, in either case, in the amount obtained by
multiplying (a) the number of shares of Common Stock designated by the Holder in
the subscription form by (b) the Purchase Price then in effect. On any partial
exercise the Company will forthwith issue and deliver to or upon the order of
the Holder a new Warrant or Warrants of like tenor, in the name of the Holder or
as the Holder (upon payment by the Holder of any applicable transfer taxes) may
request, providing in the aggregate on the face or faces thereof for the
purchase of the number of shares of Common Stock for which such Warrant or
Warrants may still be exercised. The subscription form may be surrendered by
telephone line facsimile transmission to such telephone number for the Company
as shall have been specified in writing to the Holder by the Company; PROVIDED,
HOWEVER, that if the subscription form is given to the Company by telephone line
facsimile transmission the Holder shall send an original of such subscription
form to the Company within five Business Days after such subscription form is so
given to the Company; PROVIDED FURTHER, HOWEVER, that any delay on the part of
the Holder in giving such original of any subscription form shall not affect the
validity or the date on which such subscription form is so given by telephone
line facsimile transmission.

          1.2       NET ISSUANCE. Notwithstanding anything to the contrary
contained in Section 1.1, the Holder may elect to exercise this Warrant, in
whole or in part, by receiving shares of Common Stock having an aggregate
Current Fair Market Value equal to the net issuance value (as determined below)
of this Warrant, or any part hereof, upon surrender of the subscription form
annexed hereto (duly executed by the Holder) to the Company (followed by
surrender of this Warrant to the Company within three Trading Days after
surrender of such subscription form), in which event the Company shall issue to
the Holder a number of shares of Common Stock computed using the following
formula:


                                       5
<PAGE>

                                   Y x(A-B)
                               X = --------
                                       A


         where:     X =      the number of shares of Common Stock to be issued
                             to the Holder

                    Y =      the number of shares of Common Stock as to which
                             this Warrant is to be exercised

                    A =      the Current Fair Market Value of one share of
                             Common Stock calculated as of the last Trading Day
                             immediately preceding the exercise of this Warrant

                    B =      the Purchase Price

          2.        DELIVERY OF STOCK CERTIFICATES, ETC., ON EXERCISE. As soon
as practicable after the exercise of this Warrant, and in any event within three
Trading Days thereafter, the Company at its expense (including the payment by it
of any applicable issue or stamp taxes) will cause to be issued in the name of
and delivered to the Holder, or as the Holder (upon payment by the Holder of any
applicable transfer taxes) may direct, a certificate or certificates for the
number of fully paid and nonassessable shares of Common Stock (or Other
Securities) to which the Holder shall be entitled on such exercise, in such
denominations as may be requested by the Holder, plus, in lieu of any fractional
share to which the Holder would otherwise be entitled, cash equal to such
fraction multiplied by the then Current Fair Market Value of one full share,
together with any other stock or other securities or any property (including
cash, where applicable) to which the Holder is entitled upon such exercise
pursuant to Section 1 or otherwise. Upon exercise of this Warrant as provided
herein, the Company's obligation to issue and deliver the certificates for
Common Stock shall be absolute and unconditional, irrespective of the absence of
any action by the Holder to enforce the same, any waiver or consent with respect
to any provision hereof, the recovery of any judgment against any Person or any
action to enforce the same, any failure or delay in the enforcement of any other
obligation of the Company to the Holder, or any setoff, counterclaim,
recoupment, limitation or termination, or any breach or alleged breach by the
Holder or any other Person of any obligation to the Company or any violation or
alleged violation of law by the Holder or any other Person, and irrespective of
any other circumstance which might otherwise limit such obligation of the
Company to the Holder in connection with such exercise. If the Company fails to
issue and deliver the certificates for the Common Stock to the Holder pursuant
to the first sentence of this paragraph as and when required to do so, in
addition to any other liabilities the Company may have hereunder and under
applicable law, the Company shall pay or reimburse the Holder on demand for all
out-of-pocket expenses including, without limitation, fees and expenses of legal
counsel incurred by the Holder as a result of such failure.

          3.        ADJUSTMENT FOR DIVIDENDS IN OTHER STOCK, PROPERTY, ETC.;
RECLASSIFICATION, ETC. In case at any time or from time to time, all the holders
of Common Stock (or Other Securities) shall have received, or (on or after the
record date fixed for the determination of stockholders eligible to receive)
shall have become entitled to receive, without payment therefor,


                                       6
<PAGE>

          (a)  other or additional stock, rights, warrants or other securities
     or property) by way of dividend, or

          (b)  any cash, or

          (c)  other or additional stock, rights, warrants or other securities
     or property (including cash) by way of spin-off, split-up,
     reclassification, recapitalization, combination of shares or similar
     corporate rearrangement,

other than additional shares of Common Stock (or Other Securities) issued as a
stock dividend or in a stock-split (adjustments in respect of which are provided
for in Section 6), then and in each such case the Holder, on the exercise hereof
as provided in Section 1, shall be entitled to receive the amount of stock,
rights, warrants and other securities and property (including cash) which the
Holder would hold on the date of such exercise if on the date thereof the Holder
had been the holder of record of the number of shares of Common Stock called for
on the face of this Warrant and had thereafter, during the period from the date
thereof to and including the date of such exercise, retained such shares and all
such other or additional stock, rights, warrants and other securities and
property (including cash) receivable by the Holder as aforesaid during such
period, giving effect to all adjustments called for during such period by
Section 4.

          4.        EXERCISE UPON A REORGANIZATION EVENT. In case of any
Reorganization Event the Company shall, as a condition precedent to the
consummation of the transactions constituting, or announced as, such
Reorganization Event, cause effective provisions to be made so that the Holder
shall have the right thereafter, by exercising this Warrant (in lieu of the
shares of Common Stock of the Company and Other Securities or property
purchasable and receivable upon exercise of the rights represented hereby
immediately prior to such transaction) to purchase the kind and amount of shares
of stock and other securities and property (including cash) receivable upon such
Reorganization Event by a holder of the number of shares of Common Stock that
might have been received upon exercise of this Warrant immediately prior to such
Reorganization Event. Any such provision shall include provisions for
adjustments in respect of such shares of stock and other securities and property
that shall be as nearly equivalent as may be practicable to the adjustments
provided for in this Warrant. The provisions of this Section 4 shall apply to
successive Reorganization Events.

          5.        TENDER OFFERS. In case a Tender Offer on or after the
Issuance Date made by the Company or any Subsidiary for all or any portion of
the Common Stock shall expire and such Tender Offer (as amended upon the
expiration thereof) shall require the payment to stockholders (based on the
acceptance (up to any maximum specified in the terms of the Tender Offer) of
Purchased Shares (as defined below)) of an aggregate consideration having a fair
market value (as determined by the Board of Directors, whose determination shall
be conclusive and described in a Board Resolution) that combined together with
(1) the aggregate of the cash plus the fair market value (as determined by the
Board of Directors, whose determination shall be conclusive and described in a
Board Resolution), as of the expiration of such Tender Offer, of consideration
payable in respect of any other Tender Offers, by the Company or any Subsidiary
for all or any portion of the Common Stock expiring within the 12 months
preceding the expiration of such Tender Offer and in respect of which no
adjustment pursuant to this Section 5 has been made and (2) the aggregate amount
of any distributions to all holders of the Company's


                                       7
<PAGE>

Common Stock made exclusively in cash within 12 months preceding the expiration
of such Tender Offer and in respect of which no adjustment pursuant to Section 3
has been made, exceeds 10% of the product of the Current Fair Market Value as of
the last time (the "Expiration Time") tenders (including tenders by a
stockholder of securities and related documentation accepting an offer by the
Company to repurchase such stockholder's shares) could have been made pursuant
to such Tender Offer (as it may be amended) TIMES the number of shares of Common
Stock outstanding (including any tendered shares) at the Expiration Time, then,
and in each such case, immediately prior to the opening of business on the day
after the date of the Expiration Time:

          (a)  the Purchase Price shall be adjusted so that the same shall equal
     the price determined by multiplying the Purchase Price in effect
     immediately prior to close of business on the date of the Expiration Time
     by a fraction of which the numerator shall be the number of shares of
     Common Stock outstanding (including any tendered shares) at the Expiration
     Time multiplied by the Current Fair Market Value of the Common Stock on the
     Trading Day next succeeding the Expiration Time and the denominator shall
     be the sum of (x) the fair market value (determined as aforesaid) of the
     aggregate consideration payable to stockholders based on the acceptance (up
     to any maximum specified in the terms of the Tender Offer) of all shares
     validly tendered and not withdrawn as of the Expiration Time (the shares
     deemed so accepted, up to any such maximum, being referred to as the
     "Purchased Shares") and (y) the product of the number of shares of Common
     Stock outstanding (less any Purchased Shares) at the Expiration Time and
     the Current Fair Market Value of the Common Stock on the Trading Day next
     succeeding the Expiration Time; and

          (b)  the number of shares of Common Stock for which this Warrant may
     thereafter be exercised shall be adjusted at the time of such reduction (if
     any) in the Purchase Price to a number equal to the quotient obtained by
     dividing (x) the Aggregate Purchase Price in effect immediately prior to
     the close of business on the date of the Expiration Time BY (y) the
     Purchase Price in effect immediately after such reduction in the Purchase
     Price pursuant to clause (a) of this Section 5.

Such reduction (if any) in the Purchase Price and increase in the number of
shares of Common Stock for which the Warrant may thereafter be exercised shall
become effective immediately prior to the opening of business on the day
following the Expiration Time. In the event that the Company is obligated to
purchase shares pursuant to any such Tender Offer, but the Company is
permanently prevented by applicable law from effecting any such purchases or all
such purchases are rescinded, the Purchase Price shall again be adjusted to be
the Purchase Price which would then be in effect if such Tender Offer had not
been made. If the application of this Section 5 to any Tender Offer would result
in an increase in the Purchase Price, no adjustment shall be made for such
Tender Offer under this Section 5.

          6.        ADJUSTMENT FOR EXTRAORDINARY EVENTS. In the event that the
Company shall (i) issue additional shares of the Common Stock as a dividend or
other distribution on outstanding Common Stock, (ii) subdivide or reclassify its
outstanding shares of Common Stock, or (iii) combine its outstanding shares of
Common Stock into a smaller number of shares of Common Stock, then, in each such
event, the Purchase Price shall, simultaneously with the


                                       8
<PAGE>

happening of such event, be adjusted by multiplying the Purchase Price in effect
immediately prior to such event by a fraction, the numerator of which shall be
the number of shares of Common Stock outstanding immediately prior to such event
and the denominator of which shall be the number of shares of Common Stock
outstanding immediately after such event, and the product so obtained shall
thereafter be the Purchase Price then in effect. The Purchase Price, as so
adjusted, shall be readjusted in the same manner upon the happening of any
successive event or events described herein in this Section 6. The Holder shall
thereafter, on the exercise hereof as provided in Section 1, be entitled to
receive that number of shares of Common Stock determined by multiplying the
number of shares of Common Stock which would be issuable on such exercise
immediately prior to such issuance by a fraction of which (i) the numerator is
the Purchase Price in effect immediately prior to such issuance and (ii) the
denominator is the Purchase Price in effect on the date of such exercise.

          7.        ISSUANCE OF RIGHTS OR WARRANTS TO COMMON STOCKHOLDERS AT
LESS THAN CURRENT FAIR MARKET VALUE. In case the Company shall on or after the
Issuance Date issue rights or warrants to all holders of its outstanding shares
of Common Stock entitling them to subscribe for or purchase shares of Common
Stock at a price per share less than the Current Fair Market Value on the record
date fixed for the determination of stockholders entitled to receive such rights
or warrants, then

          (a)       the Purchase Price shall be adjusted so that the same
     shall equal the price determined by multiplying the Purchase Price in
     effect at the opening of business on the day after such record date by a
     fraction of which the numerator shall be the number of shares of Common
     Stock outstanding at the close of business on such record date plus the
     number of shares which the aggregate offering price of the total number
     of shares so offered would purchase at such Current Fair Market Value,
     and the denominator shall be the number of shares of Common Stock
     outstanding on the close of business on such record date plus the total
     number of additional shares of Common Stock so offered for subscription
     or purchase; and

          (b)       the number of shares of Common Stock which the Holder may
     thereafter purchase upon exercise of this Warrant at the opening of
     business on the day after such record date shall be increased to a
     number equal to the quotient obtained by dividing (x) the Aggregate
     Purchase Price in effect immediately prior to such adjustment in the
     Purchase Price pursuant to clause (a) of this Section 7 BY (y) the
     Purchase Price in effect immediately after such adjustment in the
     Purchase Price pursuant to clause (a) of this Section 7.

Such adjustment shall become effective immediately after the opening of business
on the day following the record date fixed for determination of stockholders
entitled to receive such rights or warrants. To the extent that shares of Common
Stock are not delivered pursuant to such rights or warrants, upon the expiration
or termination of such rights or warrants, the Purchase Price shall be
readjusted to the Purchase Price which would then be in effect had the
adjustments made upon the issuance of such rights or warrants been made on the
basis of delivery of only the number of shares of Common Stock actually
delivered and the number of shares of Common Stock for which this Warrant may
thereafter be exercised shall be readjusted (subject to proportionate adjustment
for any intervening exercises of this Warrant) to the number which


                                       9
<PAGE>

would then be in effect had the adjustments made upon the issuance of such
rights or warrants been made on the basis of delivery of only the number of
shares of Common Stock actually delivered. In the event that such rights or
warrants are not so issued, the Purchase Price shall again be adjusted to be the
Purchase Price which would then be in effect if such record date had not been
fixed and the number of shares of Common Stock for which this Warrant may
thereafter be exercised shall again be adjusted (subject to proportionate
adjustment for any intervening exercises of this Warrant) to be the number which
would then be in effect if such record date had not been fixed. In determining
whether any rights or warrants entitle the holder to subscribe for or purchase
shares of Common Stock at less than such Current Fair Market Value, and in
determining the aggregate offering price of such shares of Common Stock, there
shall be taken into account any consideration received for such rights or
warrants, the value of such consideration, if other than cash, to be determined
by the Board of Directors.

          8.        ISSUANCE AT LESS THAN CURRENT FAIR MARKET VALUE. (a) In case
at any time on or after the Issuance Date the Company shall issue shares of its
Common Stock or Common Stock Equivalents (collectively, the "Newly Issued
Shares"), other than an issuance pro rata to all holders of its outstanding
Common Stock, at a price below the Current Fair Market Value of the Common Stock
at the time of such issuance, then following such issuance of Newly Issued
Shares the Purchase Price shall be reduced as provided in clause (b) of this
Section 8 and the number of shares of Common Stock which may be issued upon
exercise of this Warrant shall be increased as provided in clause (c) of this
Section 8.

          (b)       The reduction in the Purchase Price following any such
adjustment shall be determined by multiplying the Purchase Price immediately
prior to such adjustment by a fraction, of which the numerator shall be the sum
of (1) the number of shares of Common Stock outstanding immediately prior to the
issuance of the Newly Issued Shares (calculated on a fully-diluted basis
assuming the exercise or conversion of all options, warrants, purchase rights or
convertible securities which are exercisable or convertible at the time of the
issuance of the Newly Issued Shares) PLUS (2) the number of shares of Common
Stock which the aggregate consideration, if any, received by the Company for the
number of Newly Issued Shares would purchase at a price equal to the Current
Fair Market Value of the Common Stock at the time of such issuance, and the
denominator shall be the sum of (X) the number of shares of Common Stock
outstanding immediately prior to the issuance of the Newly Issued Shares
(calculated on a fully-diluted basis assuming the exercise or conversion of all
options, warrants, purchase rights or convertible securities which are
exercisable or convertible at the time of the issuance of the Newly Issued
Shares) PLUS (Y) the number of Newly Issued Shares. The adjustment provided for
in this Section 8(b) may be expressed as the following mathematical formula:

                              (O + (C/FMV))
                          NPP=------------- x PP
                                 ( O+N )
where,

         C        =     aggregate consideration received by the Company for the
                        Newly Issued Shares

         N        =     number of Newly Issued Shares


                                       10
<PAGE>

         O        =     number of shares of Common Stock outstanding (on a
                        fully diluted basis, as described above) immediately
                        prior to the issuance of the Newly Issued Shares

         FMV      =     Current Fair Market Value of the Common Stock at the
                        time of issuance of the Newly Issued Shares

         PP       =     Purchase Price immediately prior to the issuance of the
                        Newly Issued Shares

         NPP      =     Purchase Price immediately after the issuance of the
                        Newly Issued Shares

          (c)       If the Purchase Price is reduced in connection with the
issuance of Newly Issued Shares as provided in Section 8(b), then the number of
shares of Common Stock for which this Warrant may thereafter be exercised shall
be increased at the time of such reduction in the Purchase Price to a number
equal to the quotient obtained by dividing (x) the Aggregate Purchase Price in
effect immediately prior to such issuance of Newly Issued Shares BY (y) the
Purchase Price in effect immediately after such issuance of Newly Issued Shares
after giving effect to such reduction in the Purchase Price pursuant to Section
8(b).

          (d)       Notwithstanding the foregoing, no adjustment shall be made
under this Section 8 by reason of:

          (1) the issuance by the Company of shares of Common Stock pro rata
to all holders of the Common Stock so long as (i) any adjustment required by
Section 6 is made and (ii) the Company shall have given notice thereof to the
Holder pursuant to Section 14;

          (2) the issuance by the Company of Newly Issued Shares in an
offering for cash for the account of the Company that is underwritten on a
firm commitment basis and (i) is registered under the 1933 Act, or (ii) is
sold in an offering to "qualified institutional buyers" as defined in, and in
a transaction under, Rule 144A under the 1933 Act;

          (3) The issuance by the Company for cash of Newly Issued Shares in
connection with a strategic alliance, collaboration, joint venture,
partnership or similar arrangement of the Company with another Person which
strategic alliance, collaboration, joint venture, partnership or similar
arrangement relates to the Company's business as conducted immediately prior
thereto and which Person is engaged in a business similar or related to the
business of the Company so long as (x) the price per Newly Issued Share is
not less than 85 percent of the Current Fair Market Value of the Common Stock
on the date of issuance of such Newly Issued Shares and (y) the consideration
other than cash which the Company receives in connection with such strategic
alliance, collaboration, joint venture, partnership or similar arrangement
has a value, as determined by the Board of Directors in its reasonable
judgment and set forth in a Board Resolution, at least equal to the amount by
which (i) the product of the number of Newly Issued Shares so issued TIMES
the Current Fair Market Value of the Common Stock on the date such Newly
Issued Shares are issued exceeds (ii) the aggregate cash consideration
received by the Company for such Newly Issued Shares at the time of issuance
thereof;

          (4) issuance by the Company of Common Stock upon exercise of this
Warrant or the Other Warrants in accordance with the terms hereof and thereof;


                                       11
<PAGE>

          (5) the issuance by the Company of Common Stock upon conversion of
or as dividends on the Series A Preferred Stock in accordance with the terms
thereof;

          (6) the issuance by the Company of shares of Common Stock to any
employee, officer or director of, or consultant to, the Corporation pursuant
to any stock option plans or agreements approved by the Company's board of
directors; or

          (7) the issuance by the Company of shares of Common Stock or other
securities to any bank, equipment lessor or other similar financial
institution in connection with commercial credit arrangements, equipment
financing or similar transactions approved by the Company's board of
directors.

          9.        CANCELLATION OF WARRANT. (a) Subject to the satisfaction of
the conditions set forth in Sections 9(e) and 9(f) hereof, at any time, the
Company shall have the right, but not the obligation, on not less than ten (10)
and not more than twenty (20) Trading Days prior notice, to cancel the
Applicable Portion of this Warrant, if the Average Market Price of one share of
Common Stock (or unit of other securities deliverable hereunder) receivable upon
exercise of this Warrant shall equal or exceed the Target Price. Any notice of
cancellation shall be given within twenty (20) days after the last Trading Day
in the period of twenty (20) consecutive Trading Days which gave rise to the
right of the Company to cancel this Warrant. If the Applicable Portion of this
Warrant is canceled, the Company shall simultaneously cancel the Applicable
Portion of the Other Warrants which are Class A Warrants in accordance with
their terms that are similar to this Section 9.

          (b)       If the requirements set forth in Section 9(a) are met, and
the Company wishes to exercise its right to cancel the Applicable Portion of
this Warrant, the Company shall give a notice of cancellation not later than the
20th day prior to the date of cancellation (the "Cancellation Date").

          (c)       The notice of cancellation shall specify (i) the portion of
this Warrant to be canceled, (ii) the date fixed for cancellation, and (iii)
that the right to exercise the Applicable Portion of this Warrant that is being
canceled shall terminate at 5:00 p.m., New York City time, on the Trading Day
immediately preceding the Cancelation Date unless otherwise agreed by the
Company.

          (d)       If the Company shall have exercised its right to cancel the
Applicable Portion of this Warrant, any right to exercise such Applicable
Portion of this Warrant shall terminate at 5:00 p.m., New York City time, on the
Trading Day immediately preceding the Cancelation Date unless otherwise agreed
by the Company. On and after the Cancelation Date, unless otherwise agreed by
the Company, the Holder shall have no further rights with respect to the
Applicable Portion being so canceled.

          (e)       On the date notice of cancellation is given, the Company
shall be in compliance in all material respects with its obligations to the
Holder (including, without limitation, its obligations under the Transaction
Documents).

          (f)       On the date notice of cancellation is given, the
Registration Statement shall be effective and available for use by the selling
stockholders named therein and shall


                                       12
<PAGE>

reasonably be expected to remain effective and available for such use for the
135 days following the Cancellation Date.

          10.       TAX ADJUSTMENTS. The Company may make such reductions in the
Purchase Price, in addition to those required by Sections 3, 4, 5, 6, 7 and 8 as
the Board of Directors considers to be advisable to avoid or diminish any income
tax to holders of Common Stock or rights to purchase Common Stock resulting from
any dividend or distribution of stock (or rights to acquire stock) or from any
event treated as such for income tax purposes.

          11.       MINIMUM ADJUSTMENT. (a) No adjustment in the Purchase Price
(and no related adjustment in the number of shares of Common Stock which may
thereafter be purchased upon exercise of this Warrant) shall be required unless
such adjustment would require an increase or decrease of at least 1% in the
Purchase Price; PROVIDED, HOWEVER, that any adjustments which by reason of this
Section 11 are not required to be made shall be carried forward and taken into
account in any subsequent adjustment. All such calculations under this Warrant
shall be made by the Company and shall be made to the nearest cent or to the
nearest one hundredth of a share, as the case may be.

          (b)       No adjustment need be made for a change in the par value of
the Common Stock or from par value to no par value or from no par value to par
value.

          12.       NOTICE OF ADJUSTMENTS. Whenever the Purchase Price is
adjusted as herein provided, the Company shall promptly, but in no event later
than five business days thereafter, give a notice to the Holder setting forth
the Purchase Price and number of shares of Common Stock which may be purchased
upon exercise of this Warrant after such adjustment and setting forth a brief
statement of the facts requiring such adjustment. Failure to deliver such notice
shall not affect the legality or validity of any such adjustment.

          13.       FURTHER ASSURANCES. The Company will take all action that
may be necessary or appropriate in order that the Company may validly and
legally issue fully paid and nonassessable shares of stock, free from all taxes,
liens and charges with respect to the issue thereof, on the exercise of all or
any portion of this Warrant from time to time outstanding.

          14.       NOTICE TO HOLDER PRIOR TO CERTAIN ACTIONS. In case on or
after the Issuance Date:

          (a)       the Company shall declare a dividend (or any other
distribution) on its Common Stock (other than in cash out of retained earnings);
or

          (b)       the Company shall authorize the granting to the holders of
its Common Stock of rights or warrants to subscribe for or purchase any share of
any class or any other rights or warrants; or

          (c)       the Board of Directors shall authorize any reclassification
of the Common Stock (other than a subdivision or combination of its outstanding
Common Stock, or a change in par value, or from par value to no par value, or
from no par value to par value), or any consolidation or merger or other
business combination transaction to which the Company is a


                                       13
<PAGE>

party and for which approval of any stockholders of the Company is required, or
the sale or transfer of all or substantially all of the assets of the Company;
or

          (d)       there shall be pending the voluntary or involuntary
dissolution, liquidation or winding-up of the Company;

the Company shall give the Holder, as promptly as possible but in any event at
least ten Trading Days prior to the applicable date hereinafter specified, a
notice stating (x) the date on which a record is to be taken for the purpose of
such dividend, distribution or rights or warrants, or, if a record is not to be
taken, the date as of which the holders of Common Stock of record to be entitled
to such dividend, distribution or rights are to be determined, or (y) the date
on which such reclassification, consolidation, merger, other business
combination transaction, sale, transfer, dissolution, liquidation or winding-up
is expected to become effective or occur, and the date as of which it is
expected that holders of Common Stock of record who shall be entitled to
exchange their Common Stock for securities or other property deliverable upon
such reclassification, consolidation, merger, other business combination
transaction, sale, transfer, dissolution, liquidation or winding-up shall be
determined. Such notice shall not include any information which would be
material non-public information for purposes of the 1934 Act. Failure to give
such notice, or any defect therein, shall not affect the legality or validity of
such dividend, distribution, reclassification, consolidation, merger, sale,
transfer, dissolution, liquidation or winding-up. In the case of any such action
of which the Company gives such notice to the Holder or is required to give such
notice to the Holder, the Holder shall be entitled to give a subscription form
to exercise this Warrant in whole or in part that is contingent on the
completion of such action.

          15.       RESERVATION OF STOCK, ETC., ISSUABLE ON EXERCISE OF
WARRANTS. The Company will at all times reserve and keep available out of its
authorized but unissued shares of capital stock, solely for issuance and
delivery on the exercise of this Warrant, a sufficient number of shares of
Common Stock (or Other Securities) to effect the full exercise of this Warrant
and the exercise, conversion or exchange of any other warrant or security of the
Company exercisable for, convertible into, exchangeable for or otherwise
entitling the holder to acquire shares of Common Stock (or Other Securities),
and if at any time the number of authorized but unissued shares of Common Stock
(or Other Securities) shall not be sufficient to effect such exercise,
conversion or exchange, the Company shall take such action as may be necessary
to increase its authorized but unissued shares of Common Stock (or Other
Securities) to such number as shall be sufficient for such purposes.

          16.       TRANSFER OF WARRANT. This Warrant shall inure to the benefit
of the successors to and assigns of the Holder. This Warrant and all rights
hereunder, in whole or in part, are registrable at the office or agency of the
Company referred to below by the Holder in Person or by his duly authorized
attorney, upon surrender of this Warrant properly endorsed accompanied by the
assignment form in the form annexed hereto duly executed by the transferring
Holder.

          17.       REGISTER OF WARRANTS. The Company shall maintain, at the
principal office of the Company (or such other office as it may designate by
notice to the Holder), a register in which the Company shall record the name and
address of the Person in whose name


                                       14
<PAGE>

this Warrant has been issued, as well as the name and address of each successor
and prior owner of such Warrant. The Company shall be entitled to treat the
Person in whose name this Warrant is so registered as the sole and absolute
owner of this Warrant for all purposes.

          18.       EXCHANGE OF WARRANT. This Warrant is exchangeable, upon the
surrender hereof by the Holder at the office or agency of the Company referred
to in Section 17, for one or more new Warrants of like tenor representing in the
aggregate the right to subscribe for and purchase the number of shares of Common
Stock which may be subscribed for and purchased hereunder, each of such new
Warrants to represent the right to subscribe for and purchase such number of
shares as shall be designated by the Holder at the time of such surrender.

          19.       REPLACEMENT OF WARRANT. On receipt by the Company of
evidence reasonably satisfactory to it of the ownership of and the loss, theft,
destruction or mutilation of this Warrant and (a) in the case of loss, theft or
destruction, of indemnity from the Holder reasonably satisfactory in form to the
Company (and without the requirement to post any bond or other security), or (b)
in the case of mutilation, upon surrender and cancellation of this Warrant, the
Company will execute and deliver to the Holder a new Warrant of like tenor
without charge to the Holder.

          20.       WARRANT AGENT. The Company may, by written notice to the
Holder, appoint the transfer agent and registrar for the Common Stock as the
Company's agent for the purpose of issuing Common Stock (or Other Securities) on
the exercise of this Warrant pursuant to Section 1, and the Company may, by
written notice to the Holder, appoint an agent having an office in the United
States of America for the purpose of exchanging this Warrant pursuant to Section
18, and replacing this Warrant pursuant to Section 19, or any of the foregoing,
and thereafter any such exchange or replacement, as the case may be, shall be
made at such office by such agent.

          21.       REMEDIES. The Company stipulates that the remedies at law of
the Holder in the event of any default or threatened default by the Company in
the performance of or compliance with any of the terms of this Warrant are not
and will not be adequate, and that such terms may be specifically enforced by a
decree for the specific performance of any agreement contained herein or by an
injunction against a violation of any of the terms hereof or otherwise.

          22.       NO RIGHTS OR LIABILITIES AS A STOCKHOLDER. This Warrant
shall not entitle the Holder to any voting rights or other rights as a
stockholder of the Company. Nothing contained in this Warrant shall be construed
as conferring upon Holder hereof the right to vote or to consent or to receive
notice as a stockholder of the Company on any matters or with respect to any
rights whatsoever as a stockholder of the Company. No dividends or interest
shall be payable or accrued in respect of this Warrant or the interest
represented hereby or the Common Stock (or Other Securities) purchasable
hereunder until, and only to the extent that, this Warrant shall have been
exercised in accordance with its terms.

          23.       NOTICES, ETC. All notices and other communications from the
Company to the Holder shall be mailed by first class certified mail, postage
prepaid, at such address as may have been furnished to the Company in writing by
the Holder or at the address shown for the Holder on the register of Warrants
referred to in Section 17.


                                       15
<PAGE>

          24.       TRANSFER RESTRICTIONS. This Warrant has not been and is not
being registered under the provisions of the 1933 Act or any state securities
laws and this Warrant may not be transferred unless (1) the transferee is an
"accredited investor" (as defined in Regulation D under the 1933 Act) or a QIB
in a transfer that meets the requirements of Rule 144A and (2) the Holder shall
have delivered to the Company an opinion of counsel, reasonably satisfactory in
form, scope and substance to the Company, to the effect that this Warrant may be
sold or transferred without registration under the 1933 Act. Prior to any such
transfer, such transferee shall have represented in writing to the Company that
such transferee has requested and received from the Company all information
relating to the business, properties, operations, condition (financial or
other), results of operations or prospects of the Company deemed relevant by
such transferee; that such transferee has been afforded the opportunity to ask
questions of the Company concerning the foregoing and has had the opportunity to
obtain and review the Registration Statement (as defined in the Subscription
Agreement) and the prospectus included therein, each as amended or supplemented
to the date of transfer to such transferee, and the reports and other
information concerning the Company which at the time of such transfer have been
filed by the Company with the SEC pursuant to the 1934 Act and which are
incorporated by reference in such prospectus as of the date of such transfer. If
such transfer is intended to assign the rights and obligations under Sections
5(a), 5(b) and 8 of the Subscription Agreement, such transfer shall otherwise be
made in compliance with Section 11(j) of the Subscription Agreement.

          25.       RULE 144A INFORMATION REQUIREMENT. Within the period prior
to the expiration of the holding period applicable to sales hereof under Rule
144(k) under the 1933 Act (or any successor provision), the Company covenants
and agrees that it shall, during any period in which it is not subject to
Section 14 or 16(d) under the 1934 Act, make available to the Holder and the
holder of any shares of Common Stock issued upon exercise of this Warrant which
continue to be Restricted Securities in connection with any sale thereof and any
prospective purchaser of this Warrant from the Holder, the information required
pursuant to Rule 144A(d)(4) under the 1933 Act upon the request of the Holder
and it will take such further action as the Holder may reasonably request, all
to the extent required from time to time to enable the Holder to sell this
Warrant without registration under the 1933 Act within the limitation of the
exemption provided by Rule 144A, as Rule 144A may be amended from time to time.
Upon the request of the Holder, the Company will deliver to the Holder a written
statement as to whether it has complied with such requirements.

          26.       LEGEND. Unless theretofore registered for resale under the
1933 Act, each certificate for shares issued upon exercise of this Warrant shall
bear the following legend:

         The securities represented by this certificate have not been registered
         under the Securities Act of 1933, as amended. The securities have been
         acquired for investment and may not be resold, transferred or assigned
         in the absence of an effective registration statement for the
         securities under the Securities Act of 1933, as amended, or an opinion
         of counsel that registration is not required under said Act.

          27.       AMENDMENT; WAIVER. This Warrant and any terms hereof may be
changed, waived, discharged or terminated only by an instrument in writing
signed by the party against which enforcement of such change, waiver, discharge
or termination is sought.


                                       16
<PAGE>

          28.       MISCELLANEOUS. This Warrant shall be construed and enforced
in accordance with and governed by the internal laws of the State of New York.
The headings, captions and footers in this Warrant are for purposes of reference
only, and shall not limit or otherwise affect any of the terms hereof. The
invalidity or unenforceability of any provision hereof shall in no way affect
the validity or enforceability of any other provision.



                  [REMAINDER OF PAGE INTENTIONALLY LEFT BLANK]



                                       17
<PAGE>


          IN WITNESS WHEREOF, the Company has caused this Warrant to be executed
on its behalf by one of its officers thereunto duly authorized.

Dated:  December __, 2000                 VALENTIS, INC.



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





                                       18
<PAGE>



                                   ASSIGNMENT


          FOR VALUE RECEIVED, _________________________ hereby sell(s),
assign(s) and transfer(s) unto _________________________ (Please insert
social security or other Taxpayer Identification Number of assignee:
______________________________) the attached original, executed Warrant to
purchase ____________ shares of Common Stock of Valentis, Inc., a Delaware
corporation (the "Company"), and hereby irrevocably constitutes and appoints
_________________________ attorney to transfer the Warrant on the books of
the Company, with full power of substitution in the premises.

          In connection with any transfer of the Warrant within the period prior
to the expiration of the holding period applicable to sales thereof under Rule
144(k) under the 1933 Act (or any successor provision) (other than any transfer
pursuant to a registration statement that has been declared effective under the
1933 Act), the undersigned confirms that such Warrant is being transferred:

          [ ]        To the Company or a subsidiary thereof; or

          [ ]        To a QIB pursuant to and in compliance with Rule 144A; or

          [ ]        To an "accredited investor" (as defined in Regulation D
          under the 1933 Act) pursuant to and in compliance with the 1933 Act;
          or

          [ ]        Pursuant to and in compliance with Rule 144 under the 1933
          Act;

and unless the box below is checked, the undersigned confirms that, to the
knowledge of the undersigned, such Warrant is not being transferred to an
"affiliate" (as defined in Rule 144 under the 1933 Act) of the Company.

          [ ]        The transferee is an affiliate of the Company.

          Capitalized terms used in this Assignment and not defined in this
Assignment shall have the respective meanings provided in the Warrant.

Dated:_____________________            NAME:_________________________


                                            ________________________________
                                                     Signature(s)


                                       19
<PAGE>

                                                                       EXHIBIT 1

                              FORM OF SUBSCRIPTION

                                 VALENTIS, INC.

                   (To be signed only on exercise of Warrant)

TO:       Valentis, Inc.
          863A Mitten Road
          Burlingame, California  94010

          Attention:

          1.        The undersigned Holder of the attached original, executed
Warrant hereby elects to exercise its purchase right under such Warrant with
respect to ______________ shares (the "Exercise Shares") of Common Stock, as
defined in the Warrant, of Valentis, Inc., a Delaware corporation (the
"Company").

          2.        The undersigned Holder (check one):

   / /    (a)       elects to pay the aggregate purchase price for such shares
                    of Common Stock (i) in lawful money of the United States or
                    by the enclosed certified or official bank check payable in
                    United States dollars to the order of the Company in the
                    amount of $___________, or (ii) by wire transfer of United
                    States funds to the account of the Company in the amount of
                    $____________, which transfer has been made before or
                    simultaneously with the delivery of this Form of
                    Subscription pursuant to the instructions of the Company;

          or

    / /   (b)       elects to receive shares of Common Stock having a value
                    equal to the value of the Warrant calculated in accordance
                    with Section 1.2 of the Warrant.

          3.        Please issue a stock certificate or certificates
representing the appropriate number of shares of Common Stock in the name of the
undersigned or in such other names as is specified below:

         Name:
               ---------------------------------------------------
         Address:
                  ------------------------------------------------

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

Dated:
      ---------------------         --------------------------------------------
                                    (Signature,

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

                                    --------------------------------------------
                                                      (Address)


Note: This Subscription must be signed exactly as the name appears on the
Warrant, and to the extent that Holder requests that the certificates
representing the Exercise Shares be issued to a name other than that of the
Holder or via the Deposit Withdrawal Agent Commission system, the Holder's
signature must be guaranteed by an eligible guarantor institution such as a
bank, stockbroker, savings and loan association or credit union with
membership in an approved medallion signature guarantee program.



                                       20