Certain Stock Options of Rigel Pharmaceuticals, Inc. are subject to a Lock-Up Agreement Ending on 2-JAN-2018. These Stock Options will be under lockup for 90 days starting from 4-OCT-2017 to 2-JAN-2018. Details: The executive officers and directors have agreed, subject to specified exceptions, not to directly or indirectly sell, offer, contract or grant any option to sell, pledge, transfer or dispose of any shares of common stock, options or warrants or other rights to acquire shares of common stock, or securities exchangeable or exercisable for or convertible into shares of common stock, or to acquire other securities or rights ultimately exchangeable or exercisable for or convertible into shares of common stock currently or hereafter owned either of record or beneficially, or publicly announce an intention to do any of the foregoing for a period of 90 days after the date of this prospectus supplement without the prior written consent of Jefferies LLC.