X0306 4 2012-09-26 0 0001285819 OMEROS CORP OMER 0001472158 Cable Thomas J. 1420 FIFTH AVENUE SUITE 2600 SEATTLE WA 98101-2347 1 0 0 0 Common Stock 2012-09-07 5 G 0 E 2000 0 D 97067 D Common Stock 2012-09-26 4 S 0 5000 9.6 D 92067 D Open market sale pursuant to a 10b5-1 trading plan adopted by the reporting person in accordance with Rule 10b5-1 of the Securities Exchange Act of 1934, as amended. /s/ Alex F. Sutter, attorney-in-fact on behalf of Thomas J. Cable 2012-09-28