Exhibit 10.23

AMENDMENT NO. 2 TO

ARENA PHARMACEUTICALS, INC.

AMENDED AND RESTATED SEVERANCE BENEFIT PLAN

The Arena Pharmaceuticals, Inc., Amended and Restated Severance Benefit Plan,
originally effective on January 20, 2006, amended and restated on December 30,
2008, and amended as of February 10, 2012 (as amended, the “Plan”), is hereby
further amended as of October 4, 2013, by this Amendment No. 2 as follows:

Exhibit A of the Plan is deleted and replaced with Exhibit A to this Amendment
No. 2.

To record the adoption of this Amendment No. 2, Arena Pharmaceuticals, Inc., has
caused its duly authorized officer to execute the same this 25th day of February
2014.

 

Arena Pharmaceuticals, Inc.

/s/ Jack Lief

Jack Lief President and Chief Executive Officer

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EXHIBIT A

 

PARTICIPANT:

   SEVERANCE PERIOD (IN MONTHS):  

JACK LIEF

     18   

DOMINIC BEHAN

     18   

STEVEN SPECTOR

     18   

CRAIG AUDET

     12   

ROBERT HOFFMAN

     12   

WILLIAM SHANAHAN

     12