Ownership Submission
FORM 4
Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).
UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN 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 *
ORBIMED ADVISORS LLC
  2. Issuer Name and Ticker or Trading Symbol
Mirati Therapeutics, Inc. [MRTX]
5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
_____ Director __X__ 10% Owner
_____ Officer (give title below) _____ Other (specify below)
(Last)
(First)
(Middle)
601 LEXINGTON AVENUE, 54TH FLOOR
3. Date of Earliest Transaction (Month/Day/Year)
10/29/2013
(Street)

NEW YORK, NY 10022
4. If Amendment, Date Original Filed(Month/Day/Year)
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 Acquired, Disposed of, or Beneficially Owned
1.Title of Security
(Instr. 3)
2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code
(Instr. 8)
4. Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4 and 5)
5. Amount of Securities Beneficially Owned Following Reported Transaction(s)
(Instr. 3 and 4)
6. Ownership Form: Direct (D) or Indirect (I)
(Instr. 4)
7. Nature of Indirect Beneficial Ownership
(Instr. 4)
Code V Amount (A) or (D) Price
Common Stock, par value $0.001 per share 10/29/2013   P   125,000 (1) A $ 17.5 1,274,332 I See Footnotes (2) (3)

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security
(Instr. 3)
2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (Month/Day/Year) 3A. Deemed Execution Date, if any (Month/Day/Year) 4. Transaction Code
(Instr. 8)
5. Number of Derivative Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4, and 5)
6. Date Exercisable and Expiration Date
(Month/Day/Year)
7. Title and Amount of Underlying Securities
(Instr. 3 and 4)
8. Price of Derivative Security
(Instr. 5)
9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s)
(Instr. 4)
10. Ownership Form of Derivative Security: Direct (D) or Indirect (I)
(Instr. 4)
11. Nature of Indirect Beneficial Ownership
(Instr. 4)
Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares

Reporting Owners

Reporting Owner Name / Address Relationships
 Director  10% Owner  Officer  Other
ORBIMED ADVISORS LLC
601 LEXINGTON AVENUE, 54TH FLOOR
NEW YORK, NY 10022
    X    
OrbiMed Capital GP IV LLC
601 LEXINGTON AVENUE, 54TH FLOOR
NEW YORK, NY 10022
    X    
ISALY SAMUEL D
601 LEXINGTON AVENUE, 54TH FLOOR
NEW YORK, NY 10022
    X    

Signatures

 /s/ Samuel D. Isaly   10/31/2013
**Signature of Reporting Person Date

Explanation of Responses:

* If the form is filed by more than one reporting person, see Instruction 4(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) Represents shares of common stock of the Issuer ("Shares") purchased by OrbiMed Private Investments IV, LP ("OPI IV") in a secondary offering pursuant to a registration statement on Form S-1 (File No. 333-191544) that was completed on October 29, 2013.
(2) These Shares are held of record by OPI IV and may be deemed to be indirectly beneficially owned by OrbiMed Capital GP IV LLC ("GP IV"), OrbiMed Advisors LLC ("Advisors"), and Samuel D. Isaly ("Isaly"). GP IV is the sole general partner of OPI IV. Advisors, a registered adviser under the Investment Advisers Act of 1940, as amended, is the sole managing member of GP IV. By virtue of such relationships, GP IV and Advisors may be deemed to have voting and investment power with respect to the securities held by OPI IV noted above. Isaly, a natural person, is the managing member of and owner of a controlling interest in Advisors, and in such capacity may also be deemed to have voting and investment power over the securities held by OPI IV. Peter Thompson, an employee of Advisors, currently serves on the Issuer's board of directors.
(3) This Form 4 is being jointly filed by Advisors, GP IV and Isaly. Each of GP IV, Advisors and Isaly disclaims beneficial ownership of the securities reported herein for purposes of Rule 16a-1(a) under the Securities Exchange Act of 1934, as amended (the "Exchange Act"), except to the extent of its or his pecuniary interest therein, if any. This report shall not be deemed an admission that the Reporting Persons are beneficial owners for the purpose of Section 16 of the Exchange Act, or for any other purpose.

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