Joint Filer Information

Names:	Deerfield Mgmt III, L.P., Deerfield Mgmt, L.P.,  Deerfield Management Company, L.P., Deerfield Private Design Fund III, L.P., Deerfield Special Situations Fund, L.P., Deerfield Special Situations International Master Fund, L.P.,
Address:	780 Third Avenue, 37th Floor New York, NY  10017
Designated Filer:	James E. Flynn
Issuer and Ticker Symbol:	Proteon Therapeutics, Inc. [PRTO]
Date of Event Requiring Statement:	October 21, 2014

The undersigned, Deerfield Mgmt III, L.P., Deerfield Mgmt, L.P.,  Deerfield Management Company, L.P. , Deerfield Private Design Fund III, L.P.,  Deerfield Special Situations Fund, L.P. and Deerfield Special Situations International Master Fund, L.P. are jointly filing the attached Initial Statement of Beneficial Ownership on Form 3 with James E. Flynn with respect to the beneficial ownership of securities of Proteon Therapeutics, Inc.

Signatures:

DEERFIELD MGMT, L.P. By:  J.E. Flynn Capital, LLC, General Partner By:  /s/ Jonathan Isler        Jonathan Isler, Attorney-In-Fact	DEERFIELD MGMT III, L.P. By:  J.E. Flynn Capital III, LLC, General Partner By:  /s/ Jonathan Isler        Jonathan Isler, Attorney-In-Fact
DEERFIELD MANAGEMENT COMPANY, L.P. By:  Flynn Management LLC, General Partner By:  /s/ Jonathan Isler        Jonathan Isler, Attorney-In-Fact	DEERFIELD PRIVATE DESIGN FUND III, L.P. By:  Deerfield Mgmt III, L.P., General Partner By:  J.E. Flynn Capital III, LLC, General Partner By:  /s/ Jonathan Isler        Jonathan Isler, Attorney-In-Fact
DEERFIELD SPECIAL SITUATIONS FUND, L.P. By:  Deerfield Mgmt, L.P., General Partner By:  J.E. Flynn Capital, LLC, General Partner By:  /s/ Jonathan Isler        Jonathan Isler, Attorney-In-Fact
DEERFIELD SPECIAL SITUATIONS INTERNATIONAL MASTER FUND, L.P. By:  Deerfield Mgmt, L.P., General Partner By:  J.E. Flynn Capital, LLC, General Partner By:  /s/ Jonathan Isler        Jonathan Isler, Attorney-In-Fact