definiens: of a Drug Product being sold in that country ( a ) -where means a pharmaceutical product ( other than a product originally sold as a Drug Product ) that includes the same active ingredient as that used in a Drug Product -then for the period in which the sales of such Third Party Product in such country are at leastE;nty ( 20 % ) percent of the sales of the Drug Product sold by NOV ARTIS in such cou ~ tryj the royalties payable to VERTEX by NOV ARTIS on sales of such Product in License, Development and Commercialization Agreement -Confidential- Page 28 such country for such period shall tffty ( 50 % ) percent of the royalties provide ~ n Section 6.3 or Section 7.4.3 hereof, but in no event shall the royalties owed for such Drug Product in such country, when combined with any royalty reduction provided under Section 6.3.1 hereof, reduce the royalties payable on Net Sales of such Drug Product in that country by more thanEiny ( 50 % ) percent, or result in a net royalty rate payable on Net Sales of such Drug Product in such country of less than five ( 5 % ) per:~ntJ 6.4 Performance Reductions . The Research Agreement provides that VERTEX will attempt during the tenn of that Agreement to produce Drug Candidates that have successfully completed Proof of Concept Studies as defined in the Research Agreement . NOV ARTIS has an option ( the ) to license anyone or more of those Drug Candidates under the tenns of the Research Agreement . If at the end of the Extended Development Period ( the ), VERTEX has not presented to NOV ARTIS at leastI ~ee ( 3 ) Drug candida ~ as to which NOV ARTIS has exercised its Development Election, then the royalty rate otherwise payable to VERTEX under Section 6.3 or Section 7.4.3 hereof on Net Sales made after the Expiration Date ( but before considering the effect of Sections 6.3.1 or 6.3.2 on the royalty rate otherwise applicable ) shall be reduced by ~ e - half ( 1~).1 In such event, the provisions of Section 6.3.1 and Section 6.3.2 above, if applicable, shall be applied thereafter only to the royalty as reduced under this section . The provisions of this section shall not be applicable if the Research Agreement is validly terminated by either party prior to the end of its six year term