definiens: means, with respect to RX-3117, ( a ) a Regulatory Authority or safety data review board for a clinical trial of RX-3117 has required ( i ) termination or suspension of all clinical trial s of RX-3117 in ( 1 ) the U.S., or ( 2 ) the United Kingdom, Germany, F rance, Italy and Spain ( or EU centralized ) ( in each case, on a basis that is not limited to such country ), or ( ii ) the withdrawal of a Regulatory Approval of RX-3117 or a Licensed Product in ( 1 ) the U.S., or ( 2 ) the United Kingdom, Germany, France, Italy and Spain ( or EU centralize d ) ( in each case, on a basis that is not limited to such countr y ), or ( b ) a Party reasonably determines in good fa ith that the medical risk / benefit balance of RX-3117 is so unfav orable that it would be incompatible with the welfa re of patients to develop or commercialize ( or to continu e to develop or commercialize ) RX-3117