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 *
Klassen Preston
  2. Issuer Name and Ticker or Trading Symbol
ARENA PHARMACEUTICALS INC [ARNA]
5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
_____ Director _____ 10% Owner
__X__ Officer (give title below) _____ Other (specify below)
EVP and CMO
(Last)
(First)
(Middle)
C/O ARENA PHARMACEUTICALS, INC., 6154 NANCY RIDGE DRIVE
3. Date of Earliest Transaction (Month/Day/Year)
01/04/2019
(Street)

SAN DIEGO, CA 92121
4. If Amendment, Date Original Filed(Month/Day/Year)
6. Individual or Joint/Group Filing(Check Applicable Line)
_X_ Form filed by One Reporting Person
___ 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 01/07/2019   M   16,000 A $ 15.1 16,000 D  
Common Stock 01/07/2019   S(1)   15,600 D $ 41.6756 (2) 400 D  
Common Stock 01/07/2019   S(1)   400 D $ 42.3175 (3) 0 D  
Common Stock 01/08/2019   M   3,000 A $ 15.1 3,000 D  
Common Stock 01/08/2019   S(1)   3,000 D $ 44 0 D  

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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
Employee Stock Option (right to buy) $ 40.94 01/04/2019   A   75,000     (4) 01/04/2026 Common Stock 75,000 $ 0 75,000 D  
Employee Performance Restricted Stock Unit (5) 01/04/2019   A   12,600 (6)     (6) 01/03/2022 Common Stock 12,600 (6) $ 0 12,600 (6) D  
Employee Stock Option (right to buy) $ 15.1 01/07/2019   M     16,000   (7) 03/20/2024 Common Stock 16,000 $ 0 113,350 D  
Employee Stock Option (right to buy) $ 15.1 01/08/2019   M     3,000   (7) 03/20/2024 Common Stock 3,000 $ 0 110,350 D  

Reporting Owners

Reporting Owner Name / Address Relationships
 Director  10% Owner  Officer  Other
Klassen Preston
C/O ARENA PHARMACEUTICALS, INC.
6154 NANCY RIDGE DRIVE
SAN DIEGO, CA 92121
      EVP and CMO  

Signatures

 /s/ Andrew J. Cronauer, as Attorney-in-Fact   01/08/2019
**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) The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan established by the reporting person.
(2) The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $41.10 to $42.01, inclusive. The reporting person undertakes to provide Arena Pharmaceuticals, Inc., any security holder of Arena Pharmaceuticals, Inc., or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in Footnotes 2 and 3 to this Form 4.
(3) The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $42.19 to $42.36, inclusive.
(4) The options vest over four years, with 25% of the shares subject to the option vesting on January 4, 2020, and the remainder of the shares vesting monthly over the following three years in equal installments (except as otherwise necessary to avoid vesting of a fractional share), and are exercisable once vested.
(5) Each Employee Performance Restricted Stock Unit ("PRSU") represents a contingent right to receive shares of Arena's common stock, which shares shall vest, if at all, upon the closing price of Arena's common stock (the "Closing Price") reaching certain thresholds during the three-year performance period from January 4, 2019 through January 3, 2022 (the "Performance Period") and satisfaction of a continuing service requirement.
(6) The number of shares that may vest is based on the Closing Price during the Performance Period. If, on 5 consecutive or 10 non-consecutive trading days during the Performance Period, the Closing Price equals or exceeds $60, $67.50 or $75, and the reporting person thereafter satisfies a continuing service requirement, the PRSUs are deemed vested at 50%, 100% or 200%, respectively, of the target amount reported in Column 7 (subject, in the event of a change of control, to additional vesting in circumstances where the per share transaction consideration falls in between the dollar values listed above), and the reporting person will receive at or following the time of vesting a number of shares equal to the achieved percentage multiplied by the total number of PRSUs. For the avoidance of doubt, shares may be issued following achievement of each price threshold, and the maximum number of shares that may be issued pursuant to the PRSUs equals 200% of the number of PRSUs reported in Column 5.
(7) The options vest over four years and are exercisable once vested. 25% vested and became exercisable on March 20, 2018. The remainder of the options vest in thirty-six equal monthly installments (except as otherwise necessary to avoid vesting of a fractional share), with the first installment vesting on April 20, 2018, and the thirty-sixth installment vesting on March 20, 2021.

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