Exhibit 24.1

POWER OF ATTORNEY

KNOW ALL PERSONS BY THESE PRESENTS, that each of the persons whose names appear below appoints and constitutes George F. Horner, III his or her true
and lawful attorney-in-fact and agent, with full power of substitution and resubstitution, for him or her and in his or her name, place and stead, in any and all capacities, to
execute any and all amendments to execute any and all amendments to this Report on Form 10-K and to file the same, together with all exhibits thereto, with the Securities and
Exchange Commission and the National Association of Securities Dealers, Inc., and to furnish copies of the same to the Republic of ItalyCommissione Nazionale per le
Societa e le Boras, Borsa Italiana, S.p.A. and such other agencies, offices and persons as may be required by applicable law (including any applicable Italian law or legal
custom), granting unto said attorney-in-fact and agent, full power and authority to do and perform each and every act and thing requisite and necessary to be done in and about
the premises, as fully to all intents and purposes as he might or could do in person, hereby ratifying and confirming all that each said attorney-in-fact and agent may lawfully
do or cause to be done by virtue hereof.

|Signature                                               |  | Title                                                                              |  | Date            
|------------------------------------------------------- |  | ---------------------------------------------------------------------------------- |  | ----------------
|                                                        |  |                                                                                    |  |                 
|/s/JAMES H. CAVANAUGH, PH.D.James H. Cavanaugh, Ph.D.   |  | Chairman of the Board of Directors                                                 |  | March 3, 2003   
|/s/GEORGE F. HORNER IIIGeorge F. Horner III             |  | President, Chief Executive Officer (and principal accounting officer) and Director |  | March 3, 2003   
|/s/CLAUDIO QUARTA, PH.D.Claudio Quarta, Ph.D.           |  | Chief Operating Officer and Director                                               |  | March 3, 2003   
|Ubaldo Livolsi, Ph.D.                                   |  | Director                                                                           |  | March     , 2003
|/s/FRANCESCO PARENTI, PH.D.Francesco Parenti, Ph.D.     |  | Chief Scientific Officer and Director                                              |  | March 3, 2003   
|Constantino Ambrosio, Ph.D.                             |  | Chief of Manufacturing and Director                                                |  | March     , 2003
|/s/CHRISTOPHER T. WALSH, PH.DChristopher T. Walsh, Ph.D |  | Director                                                                           |  | March 3, 2003   
|/s/DAVID V. MILLIGAN, PH.DDavid V. Milligan, Ph.D       |  | Director                                                                           |  | March 3, 2003   
|/s/DOV A. GOLDSTEIN, M.D.Dov A. Goldstein, M.D.         |  | Vice President, Finance and Chief Financial Officer                                |  | March 3, 2003   

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