X0306 4 2015-05-12 0000907562 DYAX CORP DYAX 0001091925 KEMPNER THOMAS L C/O DYAX CORP. 55 NETWORK DRIVE BURLINGTON MA 01803-2756 1 0 0 0 Stock Option (right to buy) 26.23 2015-05-12 4 A 0 50000 0 A 2025-05-12 Common Stock 50000 50000 D Such option will become exercisable in twelve (12) substantially equal installments on each monthly anniversary of the date of grant (with any fractional shares to be cumulated and to become exercisable at the end of the earliest succeeding monthly period in which a whole share equivalent is accumulated). /s/ Andrew D. Ashe, as attorney-in-fact 2015-05-14