definiens: means any Patent Right within the Collaboration P atent Rights or PTIPatent Rights that Covers a Development Compound, B ack - Up Compound or Licensed Product ( including thecomposition of matter thereof, a method of making a Licensed Product, a method of using a Licensed Pro duct, or amethod or assay for screening for a Licensed Produc t ) ; provided, however that such Patent Right will cease to be aProduct - Specific Patent Right upon the occurrence o f any of the following : ( a ) termination of this Agr eement withrespect to all Development Compounds or Back - Up Com pounds Covered by the applicable Collaboration Pate nt Rightor PTI Patent Right or ( b ) cessation of Development or Commercialization of all Development Compounds, Back - UpCompounds or Licensed Products Covered by the appli cable Collaboration Patent Right or PTI Patent Righ t