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[COOLEY LETTERHEAD]
November 15, 2000
AeroGen, Inc.
1310 Orleans Drive
Sunnyvale, California 94089
Ladies and Gentlemen:
You have requested our opinion with respect to certain matters in connection
with the filing by AeroGen, Inc. (the "Company") of a Registration Statement on
Form S-8 (the "Registration Statement") with the Securities and Exchange
Commission covering the offering of up to 6,581,867 shares of the Company's
Common Stock, $.001 par value, (the "Shares") pursuant to its 1994 Stock Option
Plan, 1996 Stock Option Plan, 2000 Non-Employee Directors' Stock Option Plan,
2000 Employee Stock Purchase Plan and 2000 Equity Incentive Plan (the "Plans").
In connection with this opinion, we have examined the Registration Statement and
related Prospectus, your Certificate of Incorporation and Bylaws, as amended,
and such other documents, records, certificates, memoranda and other instruments
as we deem necessary as a basis for this opinion. We have assumed the
genuineness and authenticity of all documents submitted to us as originals, the
conformity to originals of all documents submitted to us as copies thereof, and
the due execution and delivery of all documents where due execution and delivery
are a prerequisite to the effectiveness thereof.
On the basis of the foregoing, and in reliance thereon, we are of the opinion
that the Shares, when sold and issued in accordance with the Plans, the
Registration Statement and related Prospectus, will be validly issued, fully
paid, and nonassessable (except as to shares issued pursuant to certain deferred
payment arrangements, which will be fully paid and nonassessable when such
deferred payments are made in full).
We consent to the filing of this opinion as an exhibit to the Registration
Statement.
Very truly yours,
COOLEY GODWARD LLP
By: /s/ Brett D. White
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Brett D. White
