QuickLinks -- Click here to rapidly navigate through this document
Exhibit 10.10
IDEC PHARMACEUTICALS CORPORATION
1988 STOCK OPTION PLAN
(Amended and Restated Through October 21, 2002)
I. PURPOSES OF THE PLAN
(a) This Stock Option Plan (the "Plan") is intended to promote the interests of IDEC Pharmaceuticals Corporation, a
Delaware corporation (the "Corporation"), by providing a method whereby key employees (including officers) of the
Corporation (or its parent or subsidiary corporations) responsible for the management, growth and financial success of
the Corporation (or its parent or subsidiary corporations) may be offered incentives and rewards which will encourage
them to acquire a proprietary interest, or otherwise increase their proprietary interest, in the Corporation and continue to
render services to the Corporation (or its parent or subsidiary corporations).
(b) The following provisions shall be applicable in determining the parent and subsidiary corporations of the
Corporation:
(i) Any corporation (other than the Corporation) in an unbroken chain of corporations ending with the
Corporation shall be considered to be a parent corporation of the Corporation, provided each such corporation
in the unbroken chain (other than the Corporation) owns, at the time of the determination, stock possessing fifty
percent (50%) or more of the total combined voting power of all classes of stock in one of the other corporations
in such chain.
(ii) Each corporation (other than the Corporation) in an unbroken chain of corporations beginning with the
Corporation shall be considered to be a subsidiary of the Corporation, provided each such corporation (other
than the last corporation) in the unbroken chain owns, at the time of the determination, stock possessing fifty
percent (50%) or more of the total combined voting power of all classes of stock in one of the other corporations
in such chain.
II. ADMINISTRATION OF T