Document:

EX-10.4

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 D-2 PREFERRED STOCK PURCHASE WARRANT

LA JOLLA PHARMACEUTICAL COMPANY

Warrant Shares: [      ] Issue Date: [      ]

THIS SERIES D-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 D-2 Preferred Stock
(the “Series D-2 Preferred Stock”). The purchase price of one Warrant Share under this
Warrant 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 Subsequent Cashless Warrants. As
used herein, “Warrants” means all such Subsequent Cashless 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)
if applicable, 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 Shares
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 Shares available hereunder shall
have the effect of lowering the outstanding number of Warrant Shares purchasable hereunder in an
amount equal to the applicable number of Warrant Shares purchased. The Holder and the Company
shall maintain records showing the number of Warrant Shares 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 Shares 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 Shares hereunder, the number of
Warrant Shares 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 Shares under this Warrant shall
be $1,000.00 per share, subject to adjustment hereunder (the “Exercise Price”).

(c) Cashless Exercise. If at any time prior to the Termination Date the Holder elects
to exercise this Warrant and on the Trading Day prior to the Exercise Date the Closing Sales Price
(as defined in the Certificate of Designations) is greater than the then applicable Conversion
Price (as defined in the Certificate of Designations) of the Series D-2 Preferred Stock, the Holder
of this Warrant may elect to exercise this Warrant in whole or in part by means of a “cashless
exercise.” In the event of a “cashless exercise,” by delivery to the Company of a duly completed
and executed Notice of Exercise in the form attached hereto, the Holder shall be entitled to
receive, without payment of any consideration, the number of Warrant Shares, rounded to the nearest
1/1000th of a Warrant Share, equal to the difference between (A) the aggregate face
amount of the number of Warrant Shares as to which the Warrant is then being exercised minus (B)
the quotient of (1) the product of (x) the face amount of the Warrant being exercised and (y) the
then Conversion Price, divided by (2) the Closing Sales Price on the Trading Day prior to the
Exercise Date.

(d) 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 if applicable, 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 (or by
cashless exercise, if permitted) and all taxes required to be paid by the Holder, if any, pursuant
to Section 1(d)(iv) 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 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.

(iii) Rescission Rights. If the Company fails to cause its transfer agent to transmit
to the Holder a certificate or certificates representing the Warrant Shares pursuant to this
Section 1(d)(iii) by the third (3rd) Trading Day immediately following the Warrant Share
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.

(iv) Charges, Taxes and Expenses. Issuance of certificates for Warrant Shares 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, all of which taxes and expenses shall be paid by the
Company, and such certificates 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 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.

(e) 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 D-2 Preferred Stock payable in shares of Series D-2 Preferred Stock, (B) subdivides
outstanding shares of Series D-2 Preferred Stock into a larger number of shares, or (C) combines
(including by way of reverse stock split) outstanding shares of Series D-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 D-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 D-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 D-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 D-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 D-2 Preferred Stock
(determined by dividing the amount distributed by the then issued and outstanding shares of Series
D-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 D-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 D-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 D-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 D-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 D-2 Preferred Stock; (B) the Company shall declare a special nonrecurring
cash dividend on or a redemption of the Common Stock or the Series D-2 Preferred Stock; (C) the
Company shall authorize the granting to all holders of the Common Stock or the Series D-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 D-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 D-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 D-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 D-2
Preferred Stock of record shall be entitled to exchange their shares of the Common Stock or the
Series D-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 Shares 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 Shares 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
Shares 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 Shares 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 Shares 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 D-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 shares of Series D-2 Preferred Stock of the Company that
may be acquired upon exercise in full of all then outstanding Warrants. 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; or (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.

** ** ** ** **

1

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.

       The undersigned hereby elects to purchase        Warrant Shares of the Company pursuant
to the terms of the net exercise provisions set forth in Section 1(c) of the attached Warrant, and
shall tender payment of 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:

2

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.

3EX-10.5

EXECUTION COPY

CHIEF EXECUTIVE OFFICER EMPLOYMENT AGREEMENT

This Chief Executive Officer Employment Agreement (“Agreement”) is entered into as of
May 24, 2010 by and between Deirdre Y. Gillespie, M.D. (“Executive”) and La Jolla
Pharmaceutical Company, a Delaware corporation (the “Company”).

WHEREAS, the Company desires to employ Executive to provide personal services to the Company,
and wishes to provide Executive with certain compensation and benefits in return for her services;
and

WHEREAS, Executive wishes to be employed by the Company and provide personal services to the
Company in return for certain compensation and benefits.

NOW, THEREFORE, in consideration of the mutual promises and covenants contained herein, it is
hereby agreed by and between the parties hereto as follows:

	 	1.	 	Employment by the Company.

1.1 Title and Responsibilities. Subject to terms set forth herein, the Company agrees
to employ Executive in the position of President and Chief Executive Officer and Executive hereby
accepts such employment effective as of the date hereof (the “Effective Date”). During her
employment with the Company, Executive will devote her best efforts and substantially all of her
business time and attention (except for vacation periods as set forth herein and reasonable periods
of illness or other incapacity permitted by the Company’s general employment policies) to the
business of the Company.

1.2 Executive Position. Executive will continue to serve in an executive capacity and
shall perform such duties as are customarily associated with her title, consistent with the bylaws
of the Company and as reasonably required by the Board of Directors (the “Board”) of the
Company.

1.3 Company Employment Policies. The employment relationship between the parties shall
also be governed by the general employment policies and practices of the Company, including those
relating to protection of confidential information and assignment of inventions, except that if the
terms of this Agreement differ from or are in conflict with the Company’s general employment
policies or practices, this Agreement shall control.

1.4 Board of Directors. On the Effective Date, Executive shall be confirmed as a
member of the Company’s Board of Directors to serve until the next annual meeting of stockholders.
Thereafter, she will stand for election with the other directors at the annual meeting of
stockholders.

1.5 At-Will Employment. Executive’s relationship with the Company is at-will. The
Company shall have the right to terminate Executive’s employment with the Company at any time with
or without Cause and with or without notice.

	 	2.	 	Compensation.

2.1 Base Salary. Executive shall receive for services to be rendered hereunder an
initial annual Base Salary of $405,600, payable on a biweekly basis in accordance with the normal
payroll practices of the Company (including deductions, withholdings and collections as required by
law). Upon the closing of a Strategic Transaction (defined below), Executive’s annual Base Salary
shall increase to $421,824 and such increase shall be retroactive to the Effective Date of this
agreement. For purposes of this Agreement, “Strategic Transaction” shall have the meaning set
forth in the Company’s Certificate of Incorporation. Executive will be considered for annual
increases in base salary in accordance with Company policy and subject to review and approval by
the Compensation Committee of the Board (the “Compensation Committee”) starting with the
annual performance review in January 2011

2.2 Bonus. Executive shall be eligible to participate in the Company’s executive level
bonus plan throughout the duration of Executive’s employment with the Company.

(a) Executive’s Performance. The amount of Executive’s bonus will depend upon
Executive’s and the Company’s performance with respect to the goals to be established annually by
the Compensation Committee.

(b) Determination of Bonus. The amount of Executive’s bonus will be determined after
the close of the Company’s fiscal year and paid out in the following year. To be eligible to
receive a bonus, Executive must remain in employment with the Company throughout the entire fiscal
year. Notwithstanding the foregoing, but subject to Section 2.3(c) below, in the event that
Executive is terminated without Cause, as a result of a Constructive Termination or in connection
with a Change in Control, the amount of Executive’s bonus, if any, will be determined after the
occurrence of such event and will be paid to Executive promptly thereafter. In the case of a Change
in Control, the Board agrees to consider whether to pay Executive a bonus.

(c) No Guaranteed Bonus. Notwithstanding the foregoing, no bonus is guaranteed to
Executive. Any bonus is subject to the approval of the Board, which retains the authority to
review, grant, deny or revise any bonus in its sole discretion.

(d) Target Bonus. The initial target bonus for Executive shall be fifty percent (50%)
of her then current Base Salary.

(e) Withholding. Any bonus paid to Executive shall be subject to such withholdings as
may be required by law.

2.3 Stock Options. On the Effective Date, the Company will grant Executive options to
purchase 4,000,000 shares of common stock of the Company (the “Initial Options”) pursuant
to the terms and subject to the conditions set forth in the La Jolla Pharmaceutical Company 2010
Equity Incentive Plan (the “Plan”). The Initial Option shall vest with respect to one thirty-sixth
(1/36th) of the underlying shares monthly commencing on the Effective Date until all
options are vested. The exercise price of the Initial Options shall be the Fair Market Value (as
defined in the Plan) of the Company’s common stock on the Effective Date.

2.4. Standard Company Benefits and Vacation. Executive shall be entitled to those
benefits provided to the Company’s executives generally, including healthcare benefits, and for
which she is eligible pursuant to the terms and conditions of the relevant plans. Executive shall
be entitled to four weeks of paid vacation per year.

2.5 Business Expenses. The Company shall promptly reimburse Executive for all
reasonable and necessary business expenses incurred by Executive in connection with the business of
the Company and the performance of her duties under this Agreement, subject to Executive providing
the Company with reasonable documentation thereof.

3. Termination Of Employment.

3.1 Termination For Cause. If Executive is terminated for Cause, the Company shall pay
Executive the Base Salary then in effect, prorated to the date of termination, and any amount
earned buy not yet paid or otherwise due pursuant to Sections 2.2, 2.4 and 2.5 (collectively the
“Standard Entitlements”). All other compensation from and after such termination shall cease
(except for those benefits that must be continued pursuant to applicable law or by the terms of
such benefit plans), and Executive shall not be entitled to any severance pay or other payment or
compensation whatsoever upon such termination. If the Company terminates Executive for Cause, then
all options to purchase Common Stock of the Company held by Executive as of the date of Executive’s
termination, whether or not vested, shall immediately terminate and become unexercisable. For
purposes of this Agreement, “Cause” is defined as the occurrence of one or more of the
following: (i) Executive is convicted of or pleads guilty or nolo contendere to a felony or any
crime involving moral turpitude, embezzlement or fraud; (ii) Executive breaches this Agreement or
any Agreement entered into with the Company in a manner that materially and adversely affects the
Company; (iii) Executive commits willful misconduct which materially and adversely impacts the
Company; or (iv) Executive fails, after receipt of written notice and after receiving a period of
at least 10 business days following such notice, to follow a legal direction of the Board;
provided however, that if it is not possible to follow such direction within such 10
business day period, then Cause, in this case, shall mean the failure of Executive to follow a
legal direction of the Board as soon as reasonably practicable after the end of such 10 business
day period.

3.2 Termination Without Cause/Severance. If the Company terminates Executive’s
employment without Cause, Executive will receive the Standard Entitlements and “Severance Benefits”
as described in subsection 3.6 below provided that Executive complies with all severance conditions
set forth in subsection 3.6(d) below.

3.3 Voluntary Resignation by Executive Due To Constructive Termination/Severance. If
Executive voluntarily resigns Executive’s position with the Company at any time for Constructive
Termination, Executive will receive the Standard Entitlements and “Severance Benefits” as
described in subsection 3.6 below provided that Executive complies with all severance conditions
set forth in subsection 3.6(d) below. For purposes of this Agreement, “Constructive
Termination” shall mean any one of the following events which occurs on or after the Effective
Date of this Agreement: (i) a material reduction in Executive’s responsibilities, authority or
duties as an officer of the Company or a reduction in Executive’s title(s) as an officer
of the Company; (ii) a material diminution in the Executive’s Base Salary except for
across-the-board salary reductions based on the Company’s financial performance similarly affecting
all or substantially all senior management employees of the Company and does not exceed 15%; (iii)
a relocation of Executive’s office to a location outside of San Diego County, California; (iv) any
material breach by the Company of its obligations under this Agreement; or (v) any failure by the
Company to obtain the assumption of this Agreement by any successor or assign of the Company.

3.4 Termination Upon a Change in Control/Severance. If Executive’s employment is
terminated by Company within twelve months after a Change of Control (as the term is defined
below), other than for Cause (as defined in subsection 3.1 above), Executive shall be entitled to
receive the “Severance Benefits” as described in subsection 3.6 below provided that Executive
complies with all severance conditions set forth in subsection 3.6(d) below.

3.5 Voluntary Termination; Death or Disability.

(a) Voluntary Termination. Executive may voluntarily terminate her employment with the
Company at any time, after which no further compensation will be paid to Executive, except as
specifically set forth herein. If Executive voluntary resigns, then all unvested options to
purchase Common Stock of the Company held by Executive as of the date of Executive’s termination
shall immediately terminate and become unexercisable and all vested options held by Executive shall
remain exercisable until three months after the date of cessation of service, in the case of
incentive stock options, or six months after the date of cessation of service, in the case of
non-qualified stock options.

(b) Death or Disability. The Executive’s employment under this Agreement shall
terminate immediately and without notice by the Company upon the death or disability of the
Executive. For purposes of this Agreement, Executive will be deemed to have a disability if she
becomes physically or mentally incapacitated or disabled or otherwise unable to fully discharge her
duties hereunder for a period of 60 consecutive calendar days or for 120 days in any 360-day
period. If Executive’s employment ceases as a result of death or disability, then all
unvested options to purchase Common Stock of the Company held by Executive shall immediately
terminate and become unexercisable and all vested options held by Executive shall remain
exercisable until the one year anniversary of the date of cessation of service.

(c) No Severance Pay. In the event of Executive’s death or disability or if Executive
voluntarily terminates her employment other than due to a Constructive Termination, she will not be
entitled to severance pay, pay in lieu of notice or any other such compensation.

3.6 Severance Benefits. Effective immediately after the closing of a Strategic
Transaction (defined above), if the Company terminates Executive’s employment without Cause or if
Executive terminates her employment due to a Constructive Termination, Executive shall be entitled
to the following:

(a) Severance Payment. Executive shall be entitled to a lump sum severance payment
equal to 18 months of Executive’s then current annual Base Salary (the "Standard Severance
Payment”) but in no event less than the annual Base Salary of $405,600, payable upon effectiveness
of the Release Agreement.

(b) Stock Options. All of Executive’s then outstanding Options will immediately vest
and become exercisable and all Executive’s vested Options shall expire on the 18 month anniversary
of the termination date. Notwithstanding the foregoing, in no event shall any Option be exercisable
after the date of expiration set forth in the Plan.

(c) Healthcare Coverage. To the extent that Executive is eligible to continue her
medical coverage under COBRA, the Company will pay the premiums for Executive’s COBRA coverage as
they become due (including the premiums for any dependent coverage she elects), until the earlier
of: (i) the date Executive accepts full time employment and/or becomes covered under another plan;
(ii) the date she is otherwise no longer eligible for COBRA coverage; or (iii) 18 months after the
effective date of separation. If coverage under COBRA is not available to the Company, then
Company shall pay Executive an amount equivalent to the premiums it would have paid for Executive’s
COBRA coverage.

(d) Conditions to Receive Severance Benefits. The Severance Benefits pursuant to
subsections 3.6 (a), (b) and (c) will be paid, provided that Executive timely executes and delivers
a Release Agreement to the Company,

(e) Section 409A. Notwithstanding any provision of this Agreement to the contrary, if,
at the time of Executive’s termination of employment with the Company, Executive is a “specified
employee” as defined in Section 409A of the Internal Revenue Code (the “Code”), and one or more of
the payments or benefits received or to be received by Executive pursuant to this Agreement or
otherwise would constitute deferred compensation subject to Section 409A, then:

(i) No such payment will be made under this Agreement until the earlier of (A) the date which
is six months and one day after her “separation from service” or (B) the date of Executive’s
“death”.

(ii) For the sake of clarity, the provisions of this Section 5.3(e) only apply to the extent
required to avoid Executive’s incurrence of any penalty tax or interest under Section 409A of the
Code or any regulations or United States Treasury guidance promulgated thereunder. In addition, if
any provision of this Agreement would cause Executive to incur any penalty tax or interest under
Section 409A of the Code or any regulations or Treasury guidance promulgated thereunder, the
Company may reform such provision to maintain to the maximum extent practicable the original intent
of the applicable provision without violating the provisions of Section 409A of the Code.

3.7 Cessation. If Executive violates any provision of Sections 5, 6, 7 or 8 of this
Agreement, any severance payments or other benefits being provided to Executive will cease
immediately, and Executive will not be entitled to any further compensation from the Company.

4. Change in Control. “Change in Control” means the following and shall be
deemed to occur if any of the following events occur:

(a) Except as provided by subsection (iii) hereof, the acquisition (other than
from the Company) by any person, entity or “group,” within the meaning of Section 13(d)(3) or
14(d)(2) of the Exchange Act (excluding, for this purpose, the Company or its subsidiaries, or
any employee benefit plan of the Company or its subsidiaries which acquires beneficial ownership
of voting securities of the Company), of beneficial ownership (within the meaning of Rule 13d-3
promulgated under the Exchange Act) of forty percent (40%) or more of either the then outstanding
shares of common stock or the combined voting power of the Company’s then outstanding voting
securities entitled to vote generally in the election of directors; or

(b) Individuals who, as of the effective date of the Plan, constitute the Board (the
"Incumbent Board”) cease for any reason to constitute at least a majority of the Board,
provided that any person becoming a director subsequent to the date hereof whose election, or
nomination for election by the Company’s stockholders, is or was approved by a vote of at least a
majority of the directors then comprising the Incumbent Board (other than an election or
nomination of an individual whose initial assumption of office is in connection with an actual or
threatened election contest relating to the election of the directors of the Company, as such
terms are used in Rule 14a-11 of Regulation 14A promulgated under the Exchange Act) shall be, for
purposes of the Plan, considered as though such person were a member of the Incumbent Board; or

(c) Approval by the stockholders of the Company of a reorganization, merger or consolidation
with any other person, entity or corporation, other than:

(i) a merger or consolidation which would result in the persons holding the voting securities
of the Company outstanding immediately prior thereto continuing to hold more than fifty percent
(50%) of the combined voting power of the voting securities of the Company or its successor which
are outstanding immediately after such merger or consolidation, or

(ii) a merger or consolidation effected to implement a recapitalization of the Company (or
similar transaction) in which no person acquires forty percent (40%) or more of the combined voting
power of the Company’s then outstanding voting securities; or

(d) Approval by the stockholders of the Company of a plan of complete liquidation of the
Company or an agreement for the sale or other disposition by the Company of all or substantially
all of the Company’s assets.

(e) Any other transaction that is reasonably deemed a change of control by a majority of the
independent Board members.

Notwithstanding the foregoing, a Change in Control shall not be deemed to have occurred (1) if the
“person” is an underwriter or underwriting syndicate that has acquired the ownership of 50% or more
of the combined voting power of the Company’s then outstanding voting securities solely in
connection with a public offering of the Company’s securities, or (2) if the “person” is an
employee stock ownership plan or other employee benefit plan maintained by the Company that is
qualified under the provisions of the Employee Retirement Income Security Act of 1974, as amended.

5. Confidential Information, Rights and Duties.

5.1
Agreement.

(a) Confidential Information.

(i) Executive specifically agrees that she shall not at any time, either during or subsequent
to the term of her employment with the Company, in any fashion, form or manner, either directly or
indirectly, unless expressly consented to in writing by an executive officer of the Company, use,
divulge, disclose or communicate to any person or entity any confidential information of any kind,
nature or description concerning any matters affecting or relating to the business of the Company.
The parties to this Agreement hereby stipulate that, as between them, the above information and
items are important, material and confidential trade secrets that affect the successful conduct of
the Company’s business and its goodwill, and that any breach of any term of this section is a
material breach of this Agreement. All equipment, notebooks, documents, memoranda, reports, files,
samples, books, correspondence, lists or other written and graphic records, and the like, including
tangible or intangible computer programs, records and data, affecting or relating to the business
of the Company, which the Executive might prepare, use, construct, observe, posses or control,
shall be and shall remain the Company’s sole property.

(ii) For purposes of this Agreement, the term “confidential information” shall not include any
information that: (A) has been made public by the Company (other than by acts or omissions of
Executive in violation of this Agreement or other obligation of confidentiality); (B) is developed
by Executive independently of any information the Executive learns in the course of fulfilling her
duties hereunder; or (C) Executive is legally compelled to disclose; provided that (1)
Executive is advised by written opinion of the Executive’s counsel, who shall be reasonably
satisfactory to the Company, that she is legally required to disclose such information and (2)
Executive notifies the Company of such proposed disclosure as far in advance of its disclosure as
is practicable and uses her best efforts to obtain assurances that confidential treatment will be
accorded to such information.

(b) Non-Interference. Any wrongful interference with the Company’s business, property,
confidential information, trade secrets, clients, customers, employees or independent contractors
by Executive or any of Executive’s agents during or after the term of Executive’s employment shall
be treated and acknowledged by the parties as a material breach of this Agreement. If such
interference occurs at a time that Executive is employed by the Company, such interference shall be
grounds for the Company to terminate Executive for Cause.

5.2 Remedies. Executive’s duties under this Section 3 shall survive termination of
Executive’s employment with the Company. Executive acknowledges that a remedy at law for any breach
or threatened breach by Executive of the provisions of this Section 3 would be inadequate, and
Executive therefore agrees that the Company shall be entitled to injunctive relief in case of any
such breach or threatened breach.

6. Outside Activities.

6.1 Activities. Except as set forth on Exhibit A hereto or with the prior
written consent of the Board, Executive will not during her employment with the Company undertake
or engage in any other employment, occupation or business enterprise (other than enterprises in
which Executive is a passive investor; provided that such passive investment is consistent with
this terms of this Agreement, including this Section 4). Notwithstanding the foregoing, Executive
may engage in civic and not-for-profit activities so long as such activities do not materially
interfere with the performance of her duties hereunder and are otherwise consistent with this
Section 4.

6.2 Investments and Interests. Executive agrees not to acquire, assume or participate
in, directly or indirectly, any material position, investment or interest known by her to be
adverse or antagonistic to the Company, its business or prospects, financial or otherwise.

6.3 Non-Competition.

(a) During her employment by the Company, except on behalf of the Company, Executive will not
directly or indirectly, whether as an officer, director, stockholder, partner, proprietor,
associate, representative, consultant, or in any capacity whatsoever engage in, become financially
interested in, be employed by or have any business connection with any other person, corporation,
firm, partnership or other entity whatsoever which were known by her to

compete directly with the Company, throughout the world, in any line of business engaged in (or
planned to be engaged in) by the Company.

(b) Notwithstanding the foregoing, nothing in this Agreement shall prevent Executive from
owning for passive investment purposes less than 1% of the publicly traded common equity securities
of any company engaged in the business of the Company (so long as Executive has no power to manage,
operate, advise, consult with or control the competing enterprise and no power, alone or in
conjunction with other affiliated parties, to select a director, manager, general partner, or
similar governing official of the competing enterprise other than in connection with the normal and
customary voting powers afforded Executive in connection with any permissible equity ownership).

7. Other Agreements.

7.1 Employees. For one years immediately following the termination date of Executive’s
employment for any reason, Executive agrees not to solicit, attempt to solicit, induce, or
otherwise cause any employee of the Company to terminate his or her employment in order to become
an employee, consultant or independent contractor to or for any competitor of the Company.

7.2 Noninterference. For one year immediately following the termination date of
Executive’s employment for any reason, Executive agrees not to solicit, on Executive’s own behalf
or for any entity that is in competition with the Company, any person or entity that is doing
business with the Company or is an active prospect to do business with the Company for the purpose
of diverting Company’s business or active business opportunities in competition with Company.

8. Release. In exchange for the benefits and other consideration under this Agreement
to which Executive would not otherwise be entitled, Executive shall enter into and execute a
release substantially in the form attached hereto as Exhibit B (the “Release
Agreement”) upon her termination of employment. Unless the Release Agreement is executed by
Executive and delivered to the Company within 21 days after the termination of Executive’s
employment with the Company, and the same is not revoked, Executive shall not receive any severance
benefits provided under this Agreement.

9. General Provisions.

9.1 Notices. Any notices provided hereunder must be in writing and shall be deemed
effective upon the earlier of personal delivery (including personal delivery by facsimile
transmission) or the third day after mailing by first class mail, to the Company at its primary
office location and to Executive at her address as listed on the Company payroll.

9.2 Severability. Whenever possible, each provision of this Agreement will be
interpreted in such manner as to be effective and valid under applicable law, but if any provision
of this Agreement is held to be invalid, illegal or unenforceable in any respect under any
applicable law or rule in any jurisdiction, such invalidity, illegality or unenforceability will
not affect any other provision or any other jurisdiction, and this Agreement will be reformed,
construed and enforced in such jurisdiction as if such invalid, illegal or unenforceable
provisions had never been contained herein or therein.

9.3 Waiver. If either party should waive any breach of any provisions of this
Agreement, she or it shall not thereby be deemed to have waived any preceding or succeeding breach
of the same or any other provision of this Agreement.

9.4 Complete Agreement. This Agreement, together with the exhibits attached hereto and
incorporated herein, constitutes the entire agreement between Executive and the Company and it is
the complete, final, and exclusive embodiment of their agreement and supersedes any prior agreement
written or otherwise between Executive and the Company with regard to this subject matter. It is
entered into without reliance on any promise or representation other than those expressly contained
herein or therein, and it cannot be modified or amended except in a writing signed by an officer of
the Company.

9.5 Counterparts. This Agreement may be executed in separate counterparts, any one of
which need not contain signatures of more than one party, but all of which taken together will
constitute one and the same agreement or plan. Signatures transmitted electronically or via
facsimile shall be deemed to be original signatures.

9.6 Headings. The headings of the sections hereof are inserted for convenience only
and shall not be deemed to constitute a part hereof or thereof nor to affect the meaning thereof.

9.7 Successors and Assigns. This Agreement is intended to bind and inure to the
benefit of and be enforceable by Executive and the Company and their respective successors,
assigns, heirs, executors and administrators, except that Executive may not assign any of her
duties hereunder and she may not assign any of her rights hereunder without the written consent of
the Company.

9.8 Arbitration. To provide a mechanism for rapid and economical dispute resolution,
Executive and the Company agree that any and all disputes, claims, or causes of action, in law or
equity, arising from or relating to this Agreement (including the Release Agreement) and its
enforcement, performance, breach, or interpretation, will be resolved, to the fullest extent
permitted by law, by final, binding, and confidential arbitration before a single arbitrator held
in San Diego, California and conducted by Judicial Arbitration & Mediation

Services/Endispute (“JAMS”), under its then-existing Rules and Procedures. The parties
shall be entitled to conduct adequate discovery, and they may obtain all remedies available to the
parties as if the matter had been tried in court. The arbitrator shall issue a written decision
which specifies the findings of fact and conclusions of law on which the arbitrator’s decision is
based. Judgment upon the award rendered by the arbitrator may be entered by any court having
jurisdiction thereof. Unless otherwise required by law, the arbitrator will award reasonable
expenses (including reimbursement of the assigned arbitration costs) to the prevailing party.
Nothing in this Section 9.8 or in this Agreement is intended to prevent either Executive or the
Company from obtaining injunctive relief in a court of competent jurisdiction to prevent
irreparable harm pending the conclusion of any such arbitration.

9.9 Governing Law. All questions concerning the construction, validity and

interpretation of this Agreement will be governed by the law of the State of California as
applied to contracts made and to be performed entirely within California, excluding the rules on
conflicts of law.

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

LA JOLLA PHARMACEUTICAL COMPANY

By: /s/ Craig R. Smith, M.D.

EXECUTIVE

By: /s/ Deirdre Y. Gillespie

1

EXHIBIT A

	1.	 	The Communications Strategy Group Inc., Advisory Board Member and Senior Medical Adviser

2

EXHIBIT B

RELEASE AGREEMENT

I understand that all of my positions with La Jolla Pharmaceutical Company and its
subsidiaries and affiliates (collectively, the “Company”) terminated effective

(the “Separation Date”). The Company has agreed that if I choose to sign this Agreement,
the Company will pay me severance benefits (minus the standard withholdings and deductions)
pursuant to the terms of the Chief Executive Officer Employment Agreement entered into as of May
24, 2010 between myself and the Company (the “Employment Agreement”). I understand that I
am not entitled to any severance payment under the Employment Agreement unless I sign this release
agreement. I understand that in addition to this severance, the Company will pay me all of my
accrued salary and vacation, to which I am entitled by law regardless of whether I sign this
release agreement.

In consideration for the severance payment I am to receive under my Employment Agreement, I
agree not to use or disclose any of the Company’s proprietary information without written
authorization from an executive officer of the Company, to immediately return all Company property
and documents (including all embodiments of proprietary information) and all copies thereof in my
possession or control, and to release the Company and its current and former officers, directors,
agents, attorneys, employees, stockholders, and affiliates from any and all claims, liabilities,
demands, causes of action, attorneys’ fees, damages, or obligations of every kind and nature,
whether they are known or unknown, arising at any time prior to the date I sign this release
agreement. This general release includes, but is not limited to: all federal and state statutory
and common law claims, claims related to my employment or the termination of my employment or
related to breach of contract, tort, wrongful termination, discrimination, wages or benefits, or
claims for any form of compensation. This release is not intended to release any claims I have or
may have against any of the released parties for (a) indemnification as a director, officer, agent
or employee under applicable law, charter document or agreement, (b) severance and other
termination benefits specifically provided for in my employment agreement which constitutes a part
of the consideration for this release, (c) health or other insurance benefits based on claims
already submitted or which are covered claims properly submitted in the future, (d) vested rights
under pension, retirement or other benefit plans, or (e) in respect of events, acts or omissions
occurring after the date of this release agreement.

In releasing claims unknown to me at present, I am waiving all rights and benefits under
Section 1542 of the California Civil Code, and any law or legal principle of similar effect in any
jurisdiction: “A general release does not extend to claims which the creditor does not know or
suspect to exist in his favor at the time of executing the release, which if known by her must
have materially affected her settlement with the debtor.”

I acknowledge that I am knowingly and voluntarily waiving and releasing any rights I may
have under the federal Age Discrimination in Employment Act of 1967, as amended (the “ADEA”). I
have been advised by this writing, as required by the ADEA that: (a) my waiver and release do not
apply to any claims that may arise after my signing of this release; (b) I should consult with an
attorney prior to executing this release, (c) I have 21 days within

which to consider this release (although I may choose to voluntarily execute this release earlier);
(d) I have seven days following the execution of this release to revoke it; and (e) this release
will not be effective until the eighth day after this release agreement has been signed both by me
and by the Company (“Effective Date”).

This release agreement constitutes the complete, final and exclusive embodiment of the
entire agreement between the Company and me with regard to the subject matter hereof. I am not
relying on any promise or representation by or on behalf of the Company that is not expressly
stated herein. This release agreement may only be modified by a writing signed by both me and a
duly authorized officer of the Company.

I accept and agree to the terms and conditions stated above:

By:

Date:

ACKNOWLEDGED:

LA JOLLA PHARMACEUTICAL COMPANY

By:

Name:

Title:

Date:

3

Source: [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00174-of-00352.parquet"}, [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00174-of-00352.parquet"}]]