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EXHIBIT 5.1
November 14, 2000
ICOS Corporation
22021 - 20th Avenue S.E.
Bothell, Washington 98021
Re: Registration Statement on Form S-3
Ladies and Gentlemen:
We have acted as counsel to you in connection with the proceedings for the
authorization and issuance by ICOS Corporation. (the "Company") of up to
5,000,000 shares (the "Firm Shares") of the Company's common stock, $0.01 par
value per share (the "Common Stock"), together with an additional 750,000 shares
of Common Stock if and to the extent the underwriters exercise an over-allotment
option granted by the Company (the "Over-Allotment Shares"), and the preparation
and filing of a registration statement on Form S-3 (the "Registration
Statement") under the Securities Act of 1933, as amended (the "Securities Act"),
which you are filing with the Securities and Exchange Commission with respect to
the Firm Shares and the Over-Allotment Shares (collectively, the "Shares").
We have examined the Registration Statement and such documents and records
of the Company and other documents as we have deemed necessary for the purpose
of this opinion. Based upon the foregoing, we are of the opinion that upon the
happening of the following events:
(a) the filing and effectiveness of the Registration Statement and any
amendments thereto,
(b) due execution by the Company and registration by its registrar of the
Firm Shares and, to the extent the underwriters exercise their over-
allotment option, the Over-Allotment Shares,
(c) the offering and sale of the Firm Shares and, to the extent the
underwriters exercise their over-allotment option, the Over-Allotment
Shares, as contemplated by the Registration Statement, and
(d) receipt by the Company of the consideration required for the Firm
Shares and, to the extent the underwriters exercise their over-
allotment option, the Over-Allotment Shares, to be sold by the Company
as contemplated by the Registration Statement,
the Firm Shares and, to the extent the underwriters exercise their over-
allotment option, the Over-Allotment Shares will be duly authorized, validly
issued, fully paid and nonassessable.
We hereby consent to the filing of this opinion as an exhibit to the
Registration Statement and any amendment thereto, including any and all post-
effective amendments and any registration
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ICOS Corporation
November 14, 2000
Page 2
statement relating to the same offering that is to be effective upon filing
pursuant to Rule 462(b) under the Securities Act, and to the reference to our
firm in the Prospectus of the Registration Statement under the heading "Legal
Matters." In giving such consent, we do not thereby admit that we are in the
category of persons whose consent is required under Section 7 of the Securities
Act.
Very truly yours,
/s/ PERKINS COIE LLP
