definiens: ( as such term is defined inthe License and Collaboration Agreement among the Company, sanofi - aventis Amérique du Nord and Aventis dated as ofNovember 28, 2007 ), neither Aventis nor any of its Affiliates ( for purposes of this Section 20.16, Aventis, together withsuch Affiliates, being referred to as the ) shall : ” ( b ) Section 20.16(a ) of the Aventis Collaboration Agreement is hereby amended and restated in its entirety to read:"(a ) directly or indirectly, acquire beneficial ownership of Shares of Then Outstanding Capital Stock and/or Common StockEquivalents, or make a tender, exchange or other offer to acquire Shares of Then Outstanding Capital Stock and / orCommon Stock Equivalents, if after giving effect to such acquisition ( and assuming the full conversion into, and exerciseand exchange for, shares of Common Stock of all Common Stock Equivalents beneficially owned by the Investor ), theInvestor would beneficially own ( as defined in Rule 13d-3 under the Securities Exchange Act ) more than the StandstillLimit ; provided, however, that notwithstanding the provisions of this Section 20.16, if the number of shares constitutingShares of Then Outstanding Capital Stock is reduced or if17 the aggregate ownership of the Investor is increased as a result of a recapitalization of Regeneron, the Investor shall not berequired to dispose of any of its holdings of Shares of Then Outstanding Capital Stock even though such action resulted inInvestor ’s ownership totaling more than the Standstill Limit ; as used in this Section 20.16(a):(i ) shall mean any options, warrants or other securities or rights convertible into orexercisable or exchangeable for, whether directly or following conversion into or exercise or exchange for other options, warrants or other securities or rights, shares of Class A Stock or Common Stock ; and(ii ) shall mean ( i ) from November 28, 2007 until December 31, 2011, the lesser of ( A ) twenty - one percent(21 % ) of the Shares of Then Outstanding Capital Stock, in the case of this clause ( A ) only, calculated on a fully dilutedbasis assuming the full conversion into, or exercise or exchange for, shares of Common Stock of all Common StockEquivalents outstanding ( as such Common Stock Equivalents outstanding are calculated from Regeneron ’s most recentForm 10 - Q or Form 10 - K, as applicable, filed with the SEC ), and ( B ) twenty - five percent ( 25 % ) of the Shares of ThenOutstanding Capital Stock, and ( ii ) from and after January 1, 2012, thirty percent ( 30 % ) of the Shares of Then OutstandingCapital Stock ; ” ( c ) Notwithstanding the foregoing, if this Agreement is terminated in accordance with Section 10 hereof, the amendmentsto Section 20.16 of the Aventis Collaboration Agreement set forth above shall be of no further force or effect, and theprovisions of Section 20.16 of the Aventis Collaboration Agreement in effect immediately prior to the execution and deliveryof this Agreement shall again be in full force and effect