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EXHIBIT 23.4
[IMS HEALTH LETTERHEAD]
October 4, 2000
Ms. Stacy Pryce
AeroGen
1310 Orleans Drive
Sunnyvale, CA 94089
Re: Form #S1 333-44470
Dear Stacy,
Per our discussion today, this is to verify your use of IMS HEALTH data in your
S1 filing.
Regarding the paragraphs that reference the $3 billion in inhaled respiratory
medications sourcing IMS HEALTH, please reference this as "IMS HEALTH's Market
Segment Report." The $3 billion figure is in line with my figures.
If you have any questions, or need additional information, please call me at
(610) 832-5887.
Sincerely,
/s/ DON S. DESTEFANO
Don S. DeStefano
Business Development Manager
cc: Mary Fox
