SUPPLEMENT
NO. 1
(To Proxy
Statement/Prospectus Dated November 6, 2009)
LIGAND
PHARMACEUTICALS INCORPORATED
This
document supplements the information contained in that certain proxy
statement/prospectus, which forms a part of a registration statement on Form S-4
filed with the Securities and Exchange Commission, or SEC, by Ligand
Pharmaceuticals Incorporated, or Ligand, that constitutes a prospectus of Ligand
under Section 5 of the Securities Act of 1933, as amended, with respect to the
shares of Ligand common stock to be issued to stockholders of Neurogen
Corporation, or Neurogen, in connection with the proposed merger of Neon Signal,
LLC, a wholly owned subsidiary of Ligand, with and into Neurogen, or the merger.
The proxy statement/prospectus also constitutes a proxy statement of Neurogen
under Section 14(a) of the Securities Exchange Act of 1934, as amended, and the
rules thereunder, with respect to the special meeting of Neurogen stockholders
to consider and vote upon the proposal to adopt the Agreement and Plan of
Merger, dated as of August 23, 2009, by and among Ligand, Neon Signal, LLC, and
Neurogen, as amended, and approve the merger. This supplement is not complete
without, and may not be delivered or utilized except in connection with, the
proxy statement/prospectus, including any amendments or supplements
thereto.
The
following amends and restates the information set forth on page 111 of the proxy
statement/prospectus under the caption “Incorporation By Reference” with respect
to the documents which were filed by Neurogen with the SEC that are incorporated
by reference into the proxy statement/prospectus:
The
following documents, which were filed by Neurogen with the SEC, are incorporated
by reference and delivered with this proxy statement/prospectus, except to the
extent of information which was furnished rather than filed by Neurogen, all
such information specifically not being incorporated by reference
herein:
• The
description of Neurogen’s common stock contained in Neurogen’s Registration
Statement on Form 8-A filed on February 21, 1990, as updated by Form 8-A/A filed
with the SEC on March 5, 1990;
• Neurogen’s
definitive proxy statement on Schedule 14A filed with the SEC on June 2,
2008;
• Neurogen’s
annual report on Form 10-K for the fiscal year ended December 31,
2008;
• Neurogen’s
annual report on Form 10-K/A filed with the SEC on April 30, 2009;
• Neurogen’s
quarterly report on Form 10-Q for the fiscal quarter ended March 31, 2009 filed
with the SEC on May 15, 2009;
• Neurogen’s
quarterly report on Form 10-Q for the fiscal quarter ended June 30, 2009 filed
with the SEC on August 14, 2009;
• Neurogen’s
quarterly report on Form 10-Q for the fiscal quarter ended September 30, 2009
filed with the SEC on November 6, 2009, and Neurogen’s quarterly report on Form
10-Q/A filed with the SEC on November 9, 2009; and
• Neurogen’s
current reports on Form 8-K filed with the SEC on May 7, 2009, August 24, 2009
and November 6, 2009.
All
information in this supplement is as of November 13, 2009.
The
date of this supplement is November 13, 2009.