THIS WARRANT AND THE UNDERLYING SECURITIES HAVE NOT BEEN REGISTERED UNDER THE
SECURITIES ACT OF 1933, AS AMENDED (THE “ACT”). THEY MAY NOT BE SOLD, OFFERED
FOR SALE, PLEDGED OR HYPOTHECATED IN THE ABSENCE OF AN EFFECTIVE REGISTRATION
STATEMENT AS TO SUCH SECURITIES UNDER THE ACT OR AN OPINION OF COUNSEL
SATISFACTORY TO THE COMPANY THAT SUCH REGISTRATION IS NOT REQUIRED.

FORM OF SERIES C-2 PREFERRED STOCK PURCHASE WARRANT
LA JOLLA PHARMACEUTICAL COMPANY

Warrant Shares: [      ] Issue Date: [      ], 2010

THIS SERIES C-2 PREFERRED STOCK PURCHASE WARRANT (the “Warrant”) certifies that,
for value received, [      ] (the “Holder”) is entitled, upon the terms and
subject to the limitations on exercise and the conditions hereinafter set forth,
at any time on or after the Issue Date set forth above and on or prior to the
close of business on the three year anniversary of the Issue Date (the
“Termination Date”) but not thereafter, to subscribe for and purchase from La
Jolla Pharmaceutical Company, a Delaware corporation (the “Company”), up to
[      ] shares (the “Warrant Shares”) of the Company’s Series C-2 Preferred
Stock (the “Series C-2 Preferred Stock”) and one or more warrants to purchase
shares of the Series D-2 Preferred Stock of the Company (the “Series D-2
Preferred Stock”), substantially in the form attached hereto as Exhibit A (each
a “Series D-2 Warrant” and, collectively with the Warrant Shares, the “Warrant
Securities”) to purchase up to [      ] shares of the Series D-2 Preferred
Stock. The purchase price of one unit (the “Unit”) consisting of (i) one Warrant
Share and (ii) the corresponding Series D-2 Warrant to purchase one share of
Series D-2 Preferred Stock shall be equal to the Exercise Price, as defined in
Section 1(b). This Warrant is one of a series of warrants of like tenor issuable
by the Company under that certain Securities Purchase Agreement by and among the
Company and the Purchasers named therein, dated as of [      ], 2010 (the
“Purchase Agreement”) and referred to therein as the Cash Warrants. As used
herein, “Warrants” means all such Cash Warrants.

Section 1. Exercise.

(a) Exercise of Warrant. Exercise of the purchase rights represented by this
Warrant may be made, in whole or in part, at any time or times on or after the
Issue Date and on or before the Termination Date by delivery to the Company (the
date of such delivery, the “Exercise Date”) of both: (i) a duly executed
electronic mail copy of the Notice of Exercise annexed hereto (or such other
office or agency of the Company as it may designate by notice in writing to the
registered Holder at the address of the Holder appearing on the books of the
Company), and (ii) sufficient funds representing the Exercise Price, delivered
by wire transfer. Notwithstanding anything herein to the contrary, the Holder
shall not be required to physically surrender this Warrant to the Company until
the Holder has purchased all of the Warrant Securities available hereunder and
the Warrant has been exercised in full, in which case, the Holder shall
surrender this Warrant to the Company for cancellation within three (3) Trading
Days (as defined in the Certificate of Designations, Preferences and Rights of
Series C-1 Convertible Preferred Stock, Series C-2 Convertible Preferred Stock,
Series D-1 Convertible Preferred Stock and Series D-2 Convertible Preferred
Stock of the Company (the “Certificate of Designations”)) of the date the final
Notice of Exercise is delivered to the Company. Partial exercises of this
Warrant resulting in purchases of a portion of the total number of Warrant
Securities available hereunder shall have the effect of lowering the outstanding
number of Warrant Securities purchasable hereunder in an amount equal to the
applicable number of Warrant Securities purchased. The Holder and the Company
shall maintain records showing the number of Warrant Securities purchased and
the date of such purchases. The Company shall deliver any objection to any
Notice of Exercise within two (2) Trading Days of receipt of such notice. In the
event of any dispute or discrepancy, the records of the Holder shall be
controlling and determinative in the absence of manifest error. The Holder may
provide this Warrant, or an affidavit of lost security, to the Company within a
reasonable period after the delivery of any Notice of Exercise related to any
partial exercise of this Warrant, and the Company, at its expense, will promptly
thereafter issue and deliver to the Holder a new Warrant of like tenor,
registered in the name of the Holder and exercisable, in the aggregate, for the
remaining Warrant Securities available for purchase under this Warrant. The
Holder and any assignee, by acceptance of this Warrant, acknowledge and agree
that, by reason of the provisions of this paragraph, following the purchase of a
portion of the Warrant Securities hereunder, the number of Warrant Securities
available for purchase hereunder at any given time may be less than the amount
stated on the face hereof.

(b) Exercise Price. The exercise price of the Warrant Securities under this
Warrant shall be $1,000.00 per Unit, subject to adjustment hereunder (the
“Exercise Price”).

(c) Issuance of Series D-2 Warrants. Upon the exercise of this Warrant in whole
or in part, the Company shall issue to the Holder on the date of such exercise a
warrant to purchase shares of the Series D-2 Preferred Stock, substantially in
the form attached hereto as Exhibit A (the “Series D-2 Warrant”). Each
Series D-2 Warrant shall be exercisable for the number of shares of Series D-2
Preferred Stock equal to the number of shares of Series C-2 Preferred Stock
reflected in the Notice of Exercise delivered by the Holder pursuant to this
Warrant for the exercise hereof in connection with which such Series D-2 Warrant
is issued.

(d) Mandatory Exercise. The Holder agrees to exercise the purchase rights
represented by this Warrant in whole within three (3) Trading Days following the
closing of the first Strategic Transaction (as defined in the Certificate of
Designations) that occurs following the Issue Date, and agrees to deliver a
Notice of Exercise in connection therewith, which Notice of Exercise shall be
irrevocable. The Company shall cause to be mailed to the Holder at its last
address as it shall appear upon the Warrant Register of the Company (i) at least
three (3) Trading Days prior to the closing of the Strategic Transaction, a
notice stating the date on which such Strategic Transaction is expected to close
and (ii) within three (3) Trading Days following the closing of the Strategic
Transaction, a notice stating the date on which such Strategic Transaction
closed.

(e) Mechanics of Exercise.

(i) Delivery of Certificates Upon Exercise. Certificates for shares purchased
hereunder shall be transmitted by the transfer agent of the Company to the
Holder by physical delivery to the address specified by the Holder in the Notice
of Exercise within three (3) Trading Days from the receipt by the Company of the
Notice of Exercise and payment of the aggregate Exercise Price as set forth
above (“Warrant Share Delivery Date”). The Warrant Shares shall be deemed to
have been issued, and the Holder or any other person so designated to be named
therein shall be deemed to have become a holder of record of such shares for all
purposes, as of the date the Warrant has been exercised by payment to the
Company of the Exercise Price and all taxes required to be paid by the Holder,
if any, pursuant to Section 1(e)(vi) prior to the issuance of such shares, have
been paid. To the extent permitted by law, the Company’s obligations to issue
and deliver Warrant Shares in accordance with the terms hereof are absolute and
unconditional, irrespective of any action or inaction 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,
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 that might otherwise
limit such obligation of the Company to the Holder in connection with the
issuance of the Warrant Shares. Nothing herein shall limit the Holder’s right to
pursue any other remedies available to it hereunder, at law or in equity
including, without limitation, a decree of specific performance and/or
injunctive relief with respect to the Company’s failure to timely deliver the
Warrant Shares issuable upon exercise of the Warrant as required pursuant to the
terms hereof.

(ii) Delivery of Series D-2 Warrants Upon Exercise. The Series D-2 Warrant shall
be transmitted by the Company to the Holder by physical delivery to the address
specified by the Holder in the Notice of Exercise within three (3) Trading Days
from the receipt by the Company of the Notice of Exercise and payment of the
aggregate Exercise Price as set forth above (“Series D-2 Warrant Delivery Date”
and, together with the Warrant Share Delivery Date, the “Delivery Date”). The
Series D-2 Warrant shall be deemed to have been issued, and the Holder or any
other person so designated to be named therein shall be deemed to have become a
holder of record of such Series D-2 Warrant for all purposes, as of the date the
Warrant has been exercised by payment to the Company of the Exercise Price and
all taxes required to be paid by the Holder, if any, pursuant to
Section 1(e)(vi) prior to the issuance of such shares or Series D-2 Warrant,
have been paid. To the extent permitted by law, the Company’s obligations to
issue and deliver Series D-2 Warrants in accordance with the terms hereof are
absolute and unconditional, irrespective of any action or inaction 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, 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 that might otherwise
limit such obligation of the Company to the Holder in connection with the
issuance of the Series D-2 Warrants. Nothing herein shall limit the Holder’s
right to pursue any other remedies available to it hereunder, at law or in
equity including, without limitation, a decree of specific performance and/or
injunctive relief with respect to the Company’s failure to timely deliver the
Series D-2 Warrants issuable upon exercise of the Warrant as required pursuant
to the terms hereof.

(iii) Delivery of New Warrants Upon Exercise. If this Warrant shall have been
exercised in part, the Company shall, at the request of a Holder and upon
surrender of this Warrant certificate, at the time of delivery of the
certificate or certificates representing Warrant Shares, deliver to Holder a new
Warrant evidencing the rights of Holder to purchase the unpurchased Warrant
Shares called for by this Warrant, which new Warrant shall in all other respects
be identical with this Warrant.

(iv) Rescission Rights. If the Company fails to cause its transfer agent to
transmit to the Holder a certificate or certificates representing the Warrant
Shares or the Series D-2 Warrant pursuant to this Section 1(e) by the third
(3rd) Trading Day immediately following the Delivery Date and the payment of the
Exercise Price, then the Holder will have the right to rescind such exercise at
any time until delivery of such securities.

(v) No Fractional Shares or Scrip. No fractional shares or scrip representing
fractional shares shall be issued upon the exercise of this Warrant. As to any
fraction of a share which Holder would otherwise be entitled to purchase upon
such exercise, the Company shall at its election, either pay a cash adjustment
in respect of such final fraction in an amount equal to such fraction multiplied
by the Exercise Price or round up to the next whole share.

(vi) Charges, Taxes and Expenses. Issuance of certificates for Warrant Shares
and the Series D-2 Warrant shall be made without charge to the Holder for any
issue or transfer tax or other incidental expense in respect of the issuance of
such certificate and Series D-2 Warrant, all of which taxes and expenses shall
be paid by the Company, and such certificates and Series D-2 Warrants shall be
issued in the name of the Holder or in such name or names as may be directed by
the Holder; provided, however, that in the event certificates for Warrant Shares
or Series D-2 Warrants are to be issued in a name other than the name of the
Holder, this Warrant when surrendered for exercise shall be accompanied by the
Assignment Form attached hereto duly executed by the Holder; and the Company may
require, as a condition thereto, the payment of a sum sufficient to reimburse it
for any transfer tax incidental thereto.

(f) Closing of Books. The Company will not close its stockholder books or
records in any manner which prevents the timely exercise of this Warrant,
pursuant to the terms hereof.

Section 2. Certain Adjustments.

(a) Stock Dividends and Splits. If the Company, at any time while this Warrant
is outstanding: (A) pays a stock dividend or otherwise makes a distribution or
distributions on shares of Series C-2 Preferred Stock payable in shares of
Series C-2 Preferred Stock, (B) subdivides outstanding shares of Series C-2
Preferred Stock into a larger number of shares, or (C) combines (including by
way of reverse stock split) outstanding shares of Series C-2 Preferred Stock
into a smaller number of shares, then in each case the Exercise Price shall be
multiplied by a fraction of which the numerator shall be the number of shares of
Series C-2 Preferred Stock (excluding treasury shares, if any) outstanding
immediately before such event and of which the denominator shall be the number
of shares of Series C-2 Preferred Stock (excluding treasury shares, if any)
outstanding immediately after such event and the number of Warrant Shares
issuable upon exercise of this Warrant shall be proportionately adjusted such
that the aggregate Exercise Price of this Warrant shall remain unchanged. Any
adjustment made pursuant to this Section 2(a) shall become effective immediately
after the record date for the determination of stockholders entitled to receive
such dividend or distribution and shall become effective immediately after the
effective date in the case of a subdivision, combination or re-classification.

(b) Pro Rata Distributions. If the Company, at any time while this Warrant is
outstanding, shall distribute to all holders of Series C-2 Preferred Stock (and
not to Holders of the Warrants) evidences of its indebtedness or assets
(including cash and cash dividends) or rights or warrants to subscribe for or
purchase any security other than the Series C-2 Preferred Stock, then in each
such case the Exercise Price shall be adjusted by multiplying the Exercise Price
in effect immediately prior to the record date fixed for determination of
stockholders entitled to receive such distribution by a fraction of which the
denominator shall be the Fair Market Value (as defined below) of one Warrant
Share determined as of the record date mentioned above, and of which the
numerator shall be such Fair Market Value of one Warrant Share on such record
date less the then per share fair market value at such record date of the
portion of such assets or evidence of indebtedness so distributed applicable to
one outstanding share of the Series C-2 Preferred Stock (determined by dividing
the amount distributed by the then issued and outstanding shares of Series C-2
Preferred Stock) as determined by the Board of Directors of the Company in good
faith. In either case the adjustments shall be described in a statement provided
to the Holder of the portion of assets or evidences of indebtedness so
distributed or such subscription rights applicable to one share of Series C-2
Preferred Stock. Such adjustment shall be made whenever any such distribution is
made and shall become effective immediately after the record date mentioned
above. The “Fair Market Value” shall be determined by the Board of Directors of
the Company in good faith.

(c) Corporate Change. If, at any time while this Warrant is outstanding, the
Company effects any Corporate Change (as defined in the Certificate of
Designations), then the Warrant shall terminate immediately prior to the closing
or other consummation of the event causing the Corporate Change, provided that
the Holder shall have the right to receive, for each Warrant Share that would
have been issuable upon such exercise immediately prior to the occurrence of
such Corporate Change, the securities, cash or property (the “Alternate
Consideration”) receivable as a result of such merger, consolidation or
disposition of assets by a holder of the number of shares of Series C-2
Preferred Stock for which this Warrant is exercisable immediately prior to such
event. For purposes of any such exercise, the determination of the Exercise
Price shall be appropriately adjusted to apply to such Alternate Consideration
based on the amount of Alternate Consideration issuable in respect of one share
of Series C-2 Preferred Stock in such Corporate Change, and the Company shall
apportion the Exercise Price among the Alternate Consideration in a reasonable
manner reflecting the relative value of any different components of the
Alternate Consideration. If holders of Series C-2 Preferred Stock are given any
choice as to the securities, cash or property to be received in a Corporate
Change, then the Holder shall be given the same choice as to the Alternate
Consideration it receives upon any exercise of this Warrant in connection with
such Corporate Change. The terms of any agreement pursuant to which a Corporate
Change is effected shall include terms requiring any such successor or surviving
entity to comply with the provisions of this Section 2(c).

(d) Notice to Holder.

(i) Adjustment to Exercise Price. Whenever the Exercise Price or Warrant Shares
are adjusted pursuant to any provision of this Section 2, the Company shall
promptly mail to the Holder a notice setting forth the Exercise Price and
Warrant Shares after such adjustment and setting forth a brief statement of the
facts requiring such adjustment.

(ii) Notice to Allow Exercise by Holder. If (A) the Company shall declare a
dividend (or any other distribution in whatever form) on the Common Stock of the
Company (“Common Stock”) or the Series C-2 Preferred Stock; (B) the Company
shall declare a special nonrecurring cash dividend on or a redemption of the
Common Stock or the Series C-2 Preferred Stock; (C) the Company shall authorize
the granting to all holders of the Common Stock or the Series C-2 Preferred
Stock rights or warrants to subscribe for or purchase any shares of capital
stock of any class or of any rights; (D) the approval of any stockholders of the
Company shall be required in connection with any reclassification of the Common
Stock or the Series C-2 Preferred Stock, any consolidation or merger to which
the Company is a party, any sale or transfer of all or substantially all of the
assets of the Company, of any compulsory share exchange whereby the Common Stock
or the Series C-2 Preferred Stock is converted into other securities, cash or
property; (E) the Company shall authorize the voluntary or involuntary
dissolution, liquidation or winding up of the affairs of the Company; then, in
each case, the Company shall cause to be mailed to the Holder at its last
address as it shall appear upon the Warrant Register of the Company, at least 20
calendar days prior to the applicable record or effective date hereinafter
specified, a notice stating (x) the date on which a record is to be taken for
the purpose of such dividend, distribution, redemption, rights or warrants, or
if a record is not to be taken, the date as of which the holders of the Common
Stock or the Series C-2 Preferred Stock of record to be entitled to such
dividend, distributions, redemption, rights or warrants are to be determined or
(y) the date on which such reclassification, consolidation, merger, sale,
transfer or share exchange is expected to become effective or close, and the
date as of which it is expected that holders of the Common Stock or the
Series C-2 Preferred Stock of record shall be entitled to exchange their shares
of the Common Stock or the Series C-2 Preferred Stock for securities, cash or
other property deliverable upon such reclassification, consolidation, merger,
sale, transfer or share exchange; provided that the failure to mail such notice
or any defect therein or in the mailing thereof shall not affect the validity of
the corporate action required to be specified in such notice. Subject to
applicable law, the Holder is entitled to exercise this Warrant during the
period commencing on the date of such notice to the effective date of the event
triggering such notice. Notwithstanding the foregoing, the delivery of the
notice described in this Section 2(i) is not intended to and shall not bestow
upon the Holder any voting rights whatsoever with respect to outstanding
unexercised Warrants.

Section 3. Transfer of Warrant.

(a) Transferability. Subject to compliance with any applicable securities laws,
the conditions set forth in Section 3(d) hereof and the conditions set forth in
the Purchase Agreement, this Warrant and all rights hereunder are transferable,
in whole (not in part), upon surrender of this Warrant at the principal office
of the Company or its designated agent, together with a written assignment of
this Warrant substantially in the form attached hereto duly executed by the
Holder or its agent or attorney and funds sufficient to pay any transfer taxes
payable upon the making of such transfer. Upon such surrender and, if required,
such payment, the Company shall execute and deliver a new Warrant or Warrants in
the name of the assignee or assignees and in the denomination or denominations
specified in such instrument of assignment and this Warrant shall promptly be
cancelled. A Warrant, if properly assigned, may be exercised by a new holder for
the purchase of Warrant Securities without having a new Warrant issued.

(b) New Warrants. This Warrant may be divided or combined with other Warrants
upon presentation hereof at the aforesaid office of the Company, together with a
written notice specifying the names and denominations in which new Warrants are
to be issued, signed by the Holder or its agent or attorney. Subject to
compliance with Section 3(a), as to any transfer which may be involved in such
division or combination, the Company shall execute and deliver a new Warrant or
Warrants in exchange for the Warrant or Warrants to be divided or combined in
accordance with such notice. All Warrants issued on transfers or exchanges shall
be dated the original Issue Date and shall be identical with this Warrant except
as to the number of Warrant Securities issuable pursuant thereto.

(c) Warrant Register. The Company shall register this Warrant, upon records to
be maintained by the Company for that purpose, in the name of the record Holder
hereof from time to time. The Company may deem and treat the registered Holder
of this Warrant as the absolute owner hereof for the purpose of any exercise
hereof or any distribution to the Holder, and for all other purposes, absent
actual notice to the contrary.

(d) Transfer Restrictions. If, at the time of the surrender of this Warrant in
connection with any transfer of this Warrant, the transfer of this Warrant shall
not be registered pursuant to an effective registration statement under the
Securities Act of 1933, as amended (the “Securities Act”) and under applicable
state securities or blue sky laws, the Company may require, as a condition of
allowing such transfer, that the Holder or transferee of this Warrant, as the
case may be, furnish to the Company a written opinion of counsel satisfactory to
the Company (which opinion shall be in form, substance and scope customary for
opinions of counsel in comparable transactions) to the effect that such transfer
may be made without registration under the Securities Act and under applicable
state securities or blue sky laws, (ii) that the transferor or transferee
execute and deliver to the Company an investment letter in form and substance
acceptable to the Company and (iii) that the transferee be an “accredited
investor” as defined in Rule 501(a)(1), (a)(2), (a)(3), (a)(7), or (a)(8)
promulgated under the Securities Act or a qualified institutional buyer as
defined in Rule 144A(a)(1) promulgated under the Securities Act.

Section 4. Investment Intent; Limited Transferability.

(a) By accepting this Warrant, the Holder represents to the Company that it
understands that this Warrant has not been, and any securities obtainable upon
exercise of this Warrant may not have not been registered for sale under the
Securities Act or any state securities or “blue sky” laws and are being offered
and sold to the Holder pursuant to one or more exemptions from the registration
requirements of the Securities Act and applicable State securities or “blue sky”
laws. In the absence of an effective registration of such securities or an
exemption therefrom, any certificates for such securities shall bear a legend
substantially similar to the legend set forth in the Purchase Agreement. The
Holder understands that it may have to bear the economic risk of its investment
in this Warrant and any securities obtainable upon exercise of this Warrant for
an indefinite period of time, until such securities have been registered under
the Securities Act and any applicable state securities or “blue sky” laws and
therefore cannot be sold unless subsequently registered under such laws, or an
exemption from such registration is available. The Holder further represents to
the Company, by accepting this Warrant, that it has full power and authority to
accept this Warrant and make the representations set forth herein.

(b) The Holder agrees and acknowledges that this Warrant may not be sold,
transferred, assigned or hypothecated by the Holder except in compliance with
the provisions of the Securities Act and any applicable State securities or
“blue sky” laws.

Section 5. Miscellaneous.

(a) No Rights as Stockholder Until Exercise. This Warrant does not entitle the
Holder to any voting rights or other rights as a stockholder of the Company
prior to the exercise hereof. Upon the surrender of this Warrant and the payment
of the aggregate Exercise Price, the Warrant Securities so purchased shall be
and be deemed to be issued to such Holder as the record owner of such shares as
of the close of business on the later of the date of such surrender and payment.

(b) Loss, Theft, Destruction or Mutilation of Warrant. The Company covenants
that upon receipt by the Company of evidence reasonably satisfactory to it of
the loss, theft, destruction or mutilation of this Warrant or any stock
certificate relating to the Warrant Shares, and in case of loss, theft or
destruction, of indemnity or security reasonably satisfactory to it (which, in
the case of the Warrant, shall not include the posting of any bond), and upon
surrender and cancellation of such Warrant or stock certificate, if mutilated,
the Company will make and deliver a new Warrant or stock certificate of like
tenor and dated as of such cancellation, in lieu of such Warrant or stock
certificate.

(c) Saturdays, Sundays, Holidays, etc. If the last or appointed day for the
taking of any action or the expiration of any right required or granted herein
shall not be a Trading Day, then such action may be taken or such right may be
exercised on the next succeeding Trading Day.

(d) Authorized Shares.

The Company covenants that its issuance of this Warrant shall constitute full
authority to its officers who are charged with the duty of executing stock
certificates to execute and issue the necessary certificates for the Warrant
Shares upon the exercise of the purchase rights under this Warrant. The Company
will take all such reasonable action as may be necessary to assure that all
Warrant Securities shall be issued as provided herein without violation of any
applicable law or regulation, or of any requirements of the Trading Market (as
defined in the Certificate of Designations). The Company covenants that all
Warrant Securities that are required to be issued upon the exercise of the
purchase rights represented by this Warrant will, upon exercise of the purchase
rights represented by this Warrant, be duly authorized, validly issued, fully
paid and nonassessable and free from all taxes, liens and charges created by the
Company in respect of the issue thereof (other than taxes in respect of any
transfer occurring contemporaneously with such issue).

The Company shall not by any action, including, without limitation, amending its
certificate of incorporation or through any reorganization, transfer of assets,
consolidation, merger, dissolution, issue or sale of securities or any other
voluntary action, avoid or seek to avoid the observance or performance of any of
the terms of this Warrant, but will at all times in good faith assist in the
carrying out of all such terms and in the taking of all such actions as may be
necessary or appropriate to protect the rights of Holder as set forth in this
Warrant against impairment. Without limiting the generality of the foregoing,
the Company will (a) not increase the par value of any Warrant Shares above the
amount payable therefor upon such exercise immediately prior to such increase in
par value, (b) take all such action as may be necessary or appropriate in order
that the Company may validly and legally issue fully paid and nonassessable
Warrant Shares upon the exercise of this Warrant, and (c) use commercially
reasonable efforts to obtain all such authorizations, exemptions or consents
from any public regulatory body having jurisdiction thereof as may be necessary
to enable the Company to perform its obligations under this Warrant.

Before taking any action which would result in an adjustment in the number of
Warrant Shares for which this Warrant is exercisable or in the Exercise Price,
the Company shall obtain all such authorizations or exemptions thereof, or
consents thereto, as may be necessary from any public regulatory body or bodies
having jurisdiction thereof.

(e) Jurisdiction. All questions concerning the construction, validity,
enforcement and interpretation of this Warrant shall be determined in accordance
with the provisions of the Purchase Agreement.

(f) Restrictions. The Holder acknowledges that the Warrant Shares acquired upon
the exercise of this Warrant, if not registered, will have restrictions upon
resale imposed by state and federal securities laws:

THE SECURITIES REPRESENTED BY THIS CERTIFICATE (THE “SECURITIES”) HAVE NOT BEEN
REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE “SECURITIES ACT”)
OR ANY STATE SECURITIES LAWS AND MAY NOT BE SOLD, TRANSFERRED OR OTHERWISE
DISPOSED OF UNLESS REGISTERED UNDER THE SECURITIES ACT AND UNDER APPLICABLE
STATE SECURITIES LAWS OR THE REGISTRATION OF SUCH SECURITIES UNDER THE
SECURITIES ACT AND UNDER THE PROVISIONS OF APPLICABLE STATE SECURITIES LAWS IS
NOT REQUIRED.

(g) Nonwaiver and Expenses. No course of dealing or any delay or failure to
exercise any right hereunder on the part of Holder shall operate as a waiver of
such right or otherwise prejudice Holder’s rights, powers or remedies,
notwithstanding the fact that all rights hereunder terminate on the Termination
Date. If the Company willfully and knowingly fails to comply with any provision
of this Warrant, which results in any material damages to the Holder, the
Company shall pay to Holder such amounts as shall be sufficient to cover any
costs and expenses including, but not limited to, reasonable attorneys’ fees,
including those of appellate proceedings, incurred by Holder in collecting any
amounts due pursuant hereto or in otherwise enforcing any of its rights, powers
or remedies hereunder.

(h) Notices. Any notice, request or other document required or permitted to be
given or delivered to the Holder by the Company shall be delivered in accordance
with the notice provisions of the Purchase Agreement.

(i) Limitation of Liability. No provision hereof, in the absence of any
affirmative action by Holder to exercise this Warrant to purchase Warrant
Shares, and no enumeration herein of the rights or privileges of Holder, shall
give rise to any liability of Holder for the purchase price of any Series C-2
Preferred Stock or as a stockholder of the Company, whether such liability is
asserted by the Company or by creditors of the Company.

(j) Remedies. Holder, in addition to being entitled to exercise all rights
granted by law, including recovery of damages, will be entitled to specific
performance of its rights under this Warrant. The Company agrees that monetary
damages would not be adequate compensation for any loss incurred by reason of a
breach by it of the provisions of this Warrant and hereby agrees to waive and
not to assert the defense in any action for specific performance that a remedy
at law would be adequate.

(k) Successors and Assigns. Subject to applicable securities laws, this Warrant
and the rights and obligations evidenced hereby shall inure to the benefit of
and be binding upon the successors of the Company and the successors and
permitted assigns of Holder. The provisions of this Warrant are intended to be
for the benefit of all Holders from time to time of this Warrant and shall be
enforceable by any such Holder or holder of Warrant Shares.

(l) Amendment; Waiver. No provision of this Warrant may be waived or amended on
behalf of all holders of Warrants other than by a written instrument signed by
the Company and the holders holding at least 66-2/3% of the sum of (i) the
shares of Series C-2 Preferred Stock of the Company that may be acquired upon
exercise in full of all then outstanding Warrants and (ii) the shares of
Series D-2 Preferred Stock of the Company that may be acquired upon exercise in
full for cash of the Series D-2 Warrants that may be acquired upon exercise in
full of all then outstanding Warrants, voting together as a single class. In
addition to the foregoing, no provision of this Warrant may be amended to
increase the financial obligations of Holder under this Warrant other than by a
written instrument signed by Holder. Nothing provided in this Section 5(l) shall
limit an individual holder’s right to waive or amend any provision of any
Warrant on its own behalf. The Holder acknowledges that any amendment or waiver
effected in accordance with this Section 5(l) shall be binding upon the Holder
(and its permitted assigns) and the Company, including, without limitation, an
amendment or waiver that is not agreed to by the Holder or that has an adverse
effect on any or all holders of Warrants.

(m) Severability. Wherever possible, each provision of this Warrant shall be
interpreted in such manner as to be effective and valid under applicable law,
but if any provision of this Warrant shall be prohibited by or invalid under
applicable law, such provision shall be ineffective to the extent of such
prohibition or invalidity, without invalidating the remainder of such provisions
or the remaining provisions of this Warrant.

(n) Headings. The headings used in this Warrant are for the convenience of
reference only and shall not, for any purpose, be deemed a part of this Warrant.

(o) Force Majeure. Notwithstanding any provision herein to the contrary, the
failure of any party to timely satisfy obligations hereunder shall be excused to
the extent that (i) such failure follows the occurrence of a Force Majeure Event
(defined below), and (ii) such Force Majeure Event has materially adversely
affected the ability of such party (or its agents, including banks, transfer
agents, and clearinghouses) to perform hereunder. A failure to perform shall be
excused only for so long as the Force Majeure Event continues to materially
adversely affect such person’s ability to perform. For purposes of this Section,
“Force Majeure Event” shall mean the occurrence of any of the following events:
(a) trading in securities generally on either the Nasdaq Stock Market or the New
York Stock Exchange shall have been suspended or limited, or minimum or maximum
prices shall have been generally established on any of such stock exchanges by
the SEC or FINRA; (b) a general banking moratorium shall have been declared by
any of federal, New York or California authorities; (c) an act of war, terrorism
or hostility shall have occurred, or (d) a strike, fire, flood, earthquake,
accident or other calamity or Act of God shall have occurred.

** ** ** ** **

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IN WITNESS WHEREOF, the Company has caused this Warrant to be executed by its
officer thereunto duly authorized as of the date first above indicated.

LA JOLLA PHARMACEUTICAL COMPANY

By:
Name: Deirdre Gillespie
Title: President and Chief Executive Officer

AGREED AND ACCEPTED:

[      ]

By:
Name:
Title:

NOTICE OF EXERCISE

TO: [      ]

1. The undersigned hereby elects to purchase        Warrant Shares of the
Company pursuant to the terms of the attached Warrant, and tenders herewith
payment of the exercise price in full, together with all applicable transfer
taxes, if any.

2. Payment shall be made in lawful money of the United States.

3. Please issue a certificate or certificates representing said Warrant Shares
in the name of the undersigned or in such other name as is specified below:

The Warrant Shares shall be delivered by physical delivery of a certificate to:

4. Accredited Investor. The undersigned is an “accredited investor” as defined
in Regulation D promulgated under the Securities Act of 1933, as amended.

[SIGNATURE OF HOLDER]

Name of Investing Entity:

Signature of Authorized Signatory of Investing Entity:

Name of Authorized Signatory:

Title of Authorized Signatory:

Date:

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ASSIGNMENT FORM
(To assign the foregoing warrant, execute
this form and supply required information.
Do not use this form to exercise the warrant.)

FOR VALUE RECEIVED, all [      ] shares of the foregoing Warrant and all rights
evidenced thereby are hereby assigned to

       whose address is

      .

      

Dated:       ,       

Holder’s Signature:

Holder’s Address:

Signature Guaranteed:       

NOTE: The signature to this Assignment Form must correspond with the name as it
appears on the face of the Warrant, without alteration or enlargement or any
change whatsoever, and must be guaranteed by a bank or trust company. Officers
of corporations and those acting in a fiduciary or other representative capacity
should file proper evidence of authority to assign the foregoing Warrant.

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EXHIBIT A
Form of Series D-2 Preferred Stock Purchase Warrant

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