X0202 3 2006-10-17 0 0001298521 Trubion Pharmaceuticals, Inc TRBN 0001140484 OXFORD BIOSCIENCE PARTNERS IV LP 222 BERKELEY ST. BOSTON MA 02116 0 0 1 0 0001161302 MRNA FUND II LP 222 BERKELEY ST. BOSTON MA 02116 0 0 1 0 0001261294 BARNES JEFFREY T 222 BERKELEY ST. BOSTON MA 02116 0 0 1 0 0001286397 CARTHY MARK 222 BERKELEY ST. BOSTON MA 02116 0 0 1 0 0001262294 FLEMING JONATHAN 222 BERKELEY ST. BOSTON MA 02116 0 0 1 0 0001286396 LYTTON MICHAEL 222 BERKELEY ST. BOSTON MA 02116 0 0 1 0 0001214273 WALTON ALAN G 222 BERKELEY ST. BOSTON MA 02116 0 0 1 0 0001286541 OBP MANAGEMENT IV LP 222 BERKELEY ST. BOSTON MA 02116 0 0 1 0 Series A Convertible Preferred Stock 0 Common Stock 976592 D Series B Convertible Preferred Stock 0 Common Stock 1157717 D Series A Convertible Preferred Stock 0 Common Stock 9800 D Series B Convertible Preferred Stock 0 Common Stock 11577 D The Series A Convertible Preferred Stock is convertible into Trubion Pharmaceuticals, Inc. ("Trubion") Common Stock on a 1-for-1 basis, was convertible at the date it was acquired, has no expiration date and will convert automatically upon the closing of the initial public offering of Trubion. Securities held of record by Oxford Bioscience Partners IV L.P. ("Oxford IV"). OBP Management IV L.P. ("OBP IV"), as the sole general partner of Oxford IV may be deemed to beneficially own certain of the shares held of record by Oxford IV. OBP IV disclaims beneficial ownership of all shares held of record by Oxford IV in which OBP IV does not have an actual pecuniary interest. Each of Messrs. Barnes, Carthy, Fleming, Lytton and Walton, as the individual general partners of OBP IV, may be deemed to beneficially own certain of the shares held of record by Oxford IV. Each of Messrs. Barnes, Carthy, Fleming, Lytton and Walton disclaims beneficial ownership of all shares held of record by Oxford IV in which he does not have an actual pecuniary interest. The Series B Convertible Preferred Stock is convertible into Trubion Common Stock on a 1-for-1 basis, was convertible at the date it was acquired, has no expiration date and will convert automatically upon the closing of the initial public offering of Trubion. Securities held of record by mRNA Fund II L.P. ("mRNA"). OBP IV, as the sole general partner of mRNA may be deemed to beneficially own certain of the shares held of record by mRNA. OBP IV disclaims beneficial ownership of all shares held of record by mRNA in which OBP IV does not have an actual pecuniary interest. Each of Messrs. Barnes, Carthy, Fleming, Lytton and Walton, as the individual general partners of OBP IV, may be deemed to beneficially own certain of the shares held of record by mRNA. Each of Messrs. Barnes, Carthy, Fleming, Lytton and Walton disclaims beneficial ownership of all shares held of record by mRNA in which he does not have an actual pecuniary interest. /s/ Jonathan J. Fleming, as general partner of the general partner of Oxford Bioscience Partners IV L.P. 2006-10-17 /s/ Jonathan J. Fleming, as general partner of the general partner of mRNA Fund II L.P. 2006-10-17 /s/ Jonathan J. Fleming, as general partner of OBP Management IV L.P. 2006-10-17 /s/ Jonathan J. Fleming 2006-10-17 /s/ Raymond Charest, as attorney-in-fact for Jeffrey T. Barnes 2006-10-17 /s/ Raymond Charest, as attorney-in-fact for Mark P. Carthy 2006-10-17 /s/ Raymond Charest, as attorney-in-fact for Michael E. Lytton 2006-10-17 /s/ Raymond Charest, as attorney-in-fact for Alan G. Walton 2006-10-17