Ownership Submission
FORM 3
 UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940
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(Print or Type Responses)
1. Name and Address of Reporting Person *
  PERCEPTIVE LIFE SCIENCES MASTER FUND LTD
 2. Date of Event Requiring Statement (Month/Day/Year)
12/15/2017		 3. Issuer Name and Ticker or Trading Symbol
LA JOLLA PHARMACEUTICAL CO [LJPC]
(Last)
(First)
(Middle)
51 ASTOR PLACE, 10TH FLOOR		 4. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
_____ Director __X__ 10% Owner
_____ Officer (give title below) _____ Other (specify below)
5. If Amendment, Date Original Filed(Month/Day/Year)
(Street)

NEW YORK, NY 10003		 6. Individual or Joint/Group Filing(Check Applicable Line)
___ Form filed by One Reporting Person
_X_ Form filed by More than One Reporting Person
(City)
(State)
(Zip)
Table I - Non-Derivative Securities Beneficially Owned
1.Title of Security
(Instr. 4)		 2. Amount of Securities Beneficially Owned
(Instr. 4)		 3. Ownership Form: Direct (D) or Indirect (I)
(Instr. 5)		 4. Nature of Indirect Beneficial Ownership
(Instr. 5)
Common Stock 3,388,611
I
See footnote (1)

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly. SEC 1473 (7-02)
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Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security
(Instr. 4)		 2. Date Exercisable and Expiration Date
(Month/Day/Year)		 3. Title and Amount of Securities Underlying Derivative Security
(Instr. 4)		 4. Conversion or Exercise Price of Derivative Security 5. Ownership Form of Derivative Security: Direct (D) or Indirect (I)
(Instr. 5)		 6. Nature of Indirect Beneficial Ownership
(Instr. 5)
Date Exercisable Expiration Date Title Amount or Number of Shares

Reporting Owners

Reporting Owner Name / Address Relationships
Director 10% Owner Officer Other
PERCEPTIVE LIFE SCIENCES MASTER FUND LTD
51 ASTOR PLACE, 10TH FLOOR
NEW YORK, NY 10003		     X    
PERCEPTIVE ADVISORS LLC
51 ASTOR PLACE, 10TH FLOOR
NEW YORK, NY 10003		     X    
EDELMAN JOSEPH
51 ASTOR PLACE, 10TH FLOOR
NEW YORK, NY 10003		     X    

Signatures

/s/ Perceptive Life Sciences Master Fund Ltd., By: Perceptive Advisors LLC, its investment manager By: Joseph Edelman, its managing member 12/18/2017
**Signature of Reporting Person Date
/s/ Perceptive Advisors LLC, By: Joseph Edelman, its managing member 12/18/2017
**Signature of Reporting Person Date
/s/ Joseph Edelman 12/18/2017
**Signature of Reporting Person Date

Explanation of Responses:

* If the form is filed by more than one reporting person, see Instruction 5(b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1) The securities are directly held by Perceptive Life Sciences Master Fund Ltd. (the "Master Fund"). Perceptive Advisors LLC (the "Advisor") serves as the investment manager of Master Fund. Joseph Edelman is the managing member of the Advisor. Each of Mr. Edelman and the Advisor disclaims, for purposes of Section 16 of the Securities Exchange Act of 1934, beneficial ownership of such securities, except to the extent of his/its indirect pecuniary interest therein, and this report shall not be deemed an admission that either Mr. Edelman or the Advisor is the beneficial owner of such securities for purposes of Section 16 or for any other purposes.

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