ICOS to Release Financial Results for 2006 First Quarter on May 4, 2006

ICOS Corporation (Nasdaq:ICOS) will announce its 2006
first quarter financial results on Thursday, May 4, 2006, after the
market close. At 4:30 p.m. EDT, company management will host a webcast
discussion of financial results and related matters, including
financial guidance and future plans. Access to the discussion can be
obtained as follows.

   LIVE Access on May 4, 2006, 4:30 p.m. EDT:

   --  Phone [phone]; Passcode 824479.

   --  Webcast connection through the ICOS Web site at www.icos.com
        in the Investor/Events section.

   REPLAY Access:

   --  Phone replay accessible from May 4, 2006, 8:00 p.m. EDT, for
        24 hours at 320-365-3844, Passcode 824479.

   --  Webcast replay, available through May 11, 2006, on the ICOS
        Web site at www.icos.com in the Investor/Events section.

   Additional information on ICOS, including past press releases, is
also available at www.icos.com.

   About ICOS Corporation:

   ICOS Corporation, a biotechnology company headquartered in
Bothell, Washington, is dedicated to bringing innovative therapeutics
to patients. Through Lilly ICOS LLC, ICOS is marketing its first
product, Cialis(R) (tadalafil), for the treatment of erectile
dysfunction. ICOS is working to develop treatments for serious unmet
medical needs such as benign prostatic hyperplasia, hypertension,
pulmonary arterial hypertension, cancer and inflammatory diseases.

   The forward-looking statements contained in this press release
represent ICOS' judgment as of the date of this release. ICOS
undertakes no obligation to publicly update any forward-looking
statements. The biotechnology and pharmaceutical businesses are risky
and there can be no assurance that any particular product or product
candidate will be a commercial success.