IF YOU HELD SHARES OF COMMON STOCK IN TRIUS THERAPEUTICS, INC. (“TRIUS”) AND RECEIVED CONSIDERATION FOR YOUR SHARES IN THE ACQUISITION OF TRIUS BY CUBIST PHARMACEUTICALS, INC. (“CUBIST PHARMACEUTICALS”) AND BRGO CORPORATION, A WHOLLY-OWNED SUBSIDIARY OF CUBIST PHARMACEUTICALS (“BRGO” AND TOGETHER WITH CUBIST PHARMACEUTICALS, “CUBIST”) AT THE PRICE OF $13.50 PER SHARE IN CASH AND ONE CONTINGENT VALUE RIGHT PER SHARE, YOUR RIGHTS MAY BE AFFECTED BY THE SETTLEMENT OF A CLASS ACTION.