Prepared by MERRILL CORPORATION
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    Filed by MedImmune, Inc.
Pursuant to Rule 425 under the Securities Act of 1933
and deemed filed pursuant to Rule 14d-2 of the Securities Exchange Act of 1934
Subject Company: Aviron
Commission File No. 000-20815

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JP Morgan H&Q
20th Annual Healthcare Conference
January 10, 2002


DISCLOSURE NOTICE:

This presentation may contain, in addition to historical information, certain forward-looking statements that involve risks and uncertainties. Such statements reflect management's current views and are based on certain assumptions. Actual results could differ materially from those currently anticipated as a result of a number of factors, including risks and uncertainties discussed in MedImmune's and Aviron's filings with the SEC. MedImmune and Aviron are developing products for potential future marketing. There can be no assurance that such development efforts will succeed, that such products will receive required regulatory clearance or that, even if such regulatory clearance were received, such products would ultimately achieve commercial success. There can be no assurance that Aviron will be integrated successfully or without unanticipated costs.

Aviron stockholders and other investors are urged to read the registration statement on Form S-4, Schedule TO, preliminary prospectus, supplements, final prospectus and other exchange offer documents which have been filed by MedImmune with the Securities and Exchange Commission and the related solicitation/recommendation statement which has been filed by Aviron with the SEC. These documents contain important information which should be read carefully before any decision is made with respect to the offer. Documents filed with the SEC are available for free at the SEC's website at www.sec.gov.



Agenda



MedImmune



Synagis®
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  Humanized MAb to prevent serious RSV disease in high risk infants
2000-2001 season end-user sales $490M

Ethyol®
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  Chemoprotectant in ovarian and NSCLC
Radioprotectant in head and neck cancer
Q3 annualized end-user sales $65M

CytoGam®
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  Attenuation of cytomegalovirus disease in solid organ transplantation patients
2000 end-user sales $36M


MedImmune



Aviron Acquisition





Strategic Rationale
Excellent Strategic Fit




Strategic Rationale
Unique Ability to Assess and Execute

  R&D   Jim Young, PhD


 

Clinical

 

Frank Top, MD
Ed Connor, MD


 

Regulatory

 

Peter Patriarca, MD


 

Mfg./QC/QA

 

Gail Wasserman, PhD
Ed Goley
Ben Machielse


 

Marketing

 

Jeff Hackman


Strategic Rationale
Excellent Financial Fit



Strategic Rationale
Excellent Financial Fit

Financial Goals

 
  2002
  2003
  2006
Revenues   $900M   $1.1 - $1.25B   >$2.1B
Cash EPS   $0.65 - $0.70   $1.15 - $1.20   >$2.50

2006 Operating Metrics (Goals)



Strategic Rationale
Create Premier Biotech Company





The FluMist™ Opportunity



Influenza

Sources: MMWR 2001; American Lung Association, 3/01



Influenza

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Glezen WP. Emerging infections: pandemic influenza. Epidemiol Rev. 1996; 18(1),64-76.



Influenza


LOGO   FluMist™    
LOGO   •  >20,000 vaccinated in ~20 studies
•  Positively viewed by pediatric community
•  Anticipated by recommending bodies
•  Significant public health impact


FluMist™
Regulatory Status



Advisory Committee Outcome

FluMist™ Efficacy

FluMist™ Safety



FluMist™
Regulatory Status



Potential Label



FluMist™
Product Development Strategy



FluMist™
Commercial Structure



FluMist™
Opportunity



Combined Pipeline

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Conclusion





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Agenda
MedImmune
MedImmune
Aviron Acquisition
Strategic Rationale Excellent Strategic Fit
Strategic Rationale Unique Ability to Assess and Execute
Strategic Rationale Excellent Financial Fit
Strategic Rationale Excellent Financial Fit
Strategic Rationale Create Premier Biotech Company
The FluMist™ Opportunity
Influenza
Influenza
Influenza
FluMist™ Regulatory Status
Advisory Committee Outcome
FluMist™ Regulatory Status
Potential Label
FluMist™ Product Development Strategy
FluMist™ Commercial Structure
FluMist™ Opportunity
Combined Pipeline
Conclusion