definiens: means any event, circumst ance or change that could reasonably be expected to result, individually or in the aggregate, in a mate rial adverse effect, in any respect, on ( a ) the leg ality, validity or enforceability of any of the Transaction Documents, the Counterparty Agreement or the back - up security interest granted pursuant to Section 2.1(e ), ( b ) the right o r ability of the Seller ( or any permitted assignee ) or the Purchaser to perform any of its obligations under a ny of the Transaction Documents, in each case to wh ich it is a party, or the Counterparty Agreement or to consumma te the transactions contemplated hereunder or there under, ( c ) the rights or remedies of the Purchaser under a ny of the Transaction Documents or the Counterparty Agreement, or ( d ) the Purchased Assets ( it being un derstood and agreed, however, that any adverse effe ct on the amount, timing, duration or value of the Royalties shall constitute a Material Adverse Change )