definiens: when used herein with respect to a Party, shall mean and include each and every claim, charge, complaint, demand, action, cause of action, suit, right, debt, sum of money, cost, reckoning, covenant, contract, agreement, promise, doing, omission, damage, execution, obligation, liability, and expense ( including attorneys ’ fees andcosts ), of every kind and nature, whether at law or in equity, that such Party may have had in the past, may now have ormay have in the future against the Released Parties, and which has arisen or arises directly or indirectly out of, or relatesdirectly or indirectly to, any circumstance, agreement, activity, action, omission, event or matter occurring or 3 existing on or prior to the Effective Date to the extent such claim relates to or arises under the Collaboration Agreement;provided, however, that the Released Claims shall exclude : ( 1 ) any and all rights to seek and obtain indemnificationunder this letter agreement and the Collaboration ; and ( 2 ) any and all rights to seek and obtain enforcement of, or aremedy arising out of the breach of, any obligation provided for in this letter agreement