Trubion Pharmaceuticals Inc. today announced presentation of data at the 2008 Annual European Congress of Rheumatology meeting in Paris demonstrating that repeat administration with TRU-015 continues to produce persistent responses on the American College of Rheumatology (ACR) criteria and consistent pharmacodynamic (PD) effects

SEATTLE, WA, U.S.A. | June 16, 2008 | Trubion Pharmaceuticals Inc. (Nasdaq: TRBN) today announced presentation of data at the 2008 Annual European Congress of Rheumatology meeting in Paris demonstrating that repeat administration with TRU-015, Trubion’s lead candidate for the treatment of rheumatoid arthritis (RA), continues to produce persistent responses on the American College of Rheumatology (ACR) criteria and consistent pharmacodynamic (PD) effects. In addition, preclinical data presented at the meeting demonstrated that a single dose of SBI-087, a next-generation Small Modular ImmunoPharmaceutical (SMIP(TM)) treatment for RA, resulted in more potent B-cell depletion in peripheral blood and lymphoid tissues than rituximab. Wyeth Pharmaceuticals is developing TRU-015 and SBI-087 in collaboration with Trubion.

Repeated Therapy With TRU-015 Is Well-Tolerated With Consistent PD Profile (OP-0252)

The objective of the ongoing re-treatment study was to evaluate the safety, PD, pharmacokinetics and immunogenicity of TRU-015 for RA with repeated doses after receiving initial administration in a Phase I/IIa study. Patients treated with a single course of 5 mg/kg or higher in a previously conducted TRU-015 Phase I/IIa study were eligible for re-treatment. Patients who received a single infusion of 5 mg/kg received a single infusion of 5 mg/kg upon re-treatment, and those who received higher doses of TRU-015 received a single infusion of 15 mg/kg upon re-treatment. PD response of B-cells was also evaluated after initial treatment and after re-treatment.

Thirty-eight patients have entered the re-treatment study, and re-treatment data were available for 36 patients with some patients having received six courses of TRU-015 at the time of this assessment. Re-treatment with TRU-015 did not result in an increase in any adverse events compared with the initial infusion, and the re-treatment infusions were well-tolerated. B-cell depletion and recovery following re-treatment with TRU-015 was comparable to that seen after initial treatment. Ongoing patient evaluations showed maintenance of ACR responses following administration of a single dose of TRU-015 at six-month intervals.

Trubion announced in May that Wyeth had commenced patient dosing in the next Phase 2b clinical trial of TRU-015 in patients with RA. The randomized, parallel, double-blind, placebo-controlled, dose-regimen-finding study will evaluate the safety and efficacy of two dosing regimens. Treatment will be administered to approximately 216 patients with active, seropositive RA on a background of methotrexate. The primary outcome measurement for the TRU-015 Phase 2b study will be the ACR 50 response measured at 24 weeks. Secondary outcome measurements will be ACR 20 and Disease Activity Score-28 responses.

SBI-087 Demonstrates Favorable in Vivo B-Cell Depletion and Pharmacokinetic Profiles (THU0171)

SBI-087 is a humanized SMIP drug candidate that is directed against the CD20 antigen. The objective of the preclinical study conducted by Wyeth was to evaluate the pharmacokinetics and pharmacodynamics of SBI-087 following a single intravenous dose. Administration of SBI-087 resulted in dose-dependent B-lymphocyte depletion in peripheral blood and lymphoid tissues that was more profound and sustained in SBI-087-treated groups compared with rituximab.

In April, Trubion announced that Wyeth initiated a Phase 1 SBI-087 dose escalation clinical trial that is designed to evaluate the safety, tolerability, pharmacokinetics and pharmacodynamics of a single dose of SBI-087 in patients with RA. This Phase I trial is designed to enroll patients who meet the criteria for RA with Functional Class I, II or III, and who have been diagnosed with RA more than six months prior to the study with onset of RA after the age of 16.

"We believe SBI-087 and TRU-015 together will play an important role in improving patient care and helping us establish category leadership in autoimmune and inflammatory disease markets," said Peter Thompson, M.D., FACP, president, CEO and chairman of Trubion. "With more than 100 re-treatment courses of TRU-015 now administered, these data further demonstrate TRU-015’s ability to maintain consistent and predictable RA response rates following re-treatment with a single dose given every six months. We look forward to the results of Wyeth’s ongoing TRU-015 Phase 2b study designed to identify a preferred induction, or initial, dosing regimen. The results from this study, combined with our re-treatment experience to date, will allow us to further establish TRU-015’s competitive profile for patients with RA."

About Trubion

Trubion is a biopharmaceutical company that is creating a pipeline of novel protein therapeutic product candidates to treat autoimmune and inflammatory diseases and cancer. The company’s mission is to develop a variety of first-in-class and best-in-class product candidates, customized for optimal safety, efficacy, and convenience that it believes may offer improved patient experiences. Trubion’s current product candidates are novel single-chain protein, or SMIP(TM), therapeutics, and are designed using its custom drug assembly technology. Trubion’s product pipeline includes CD20-directed candidates such as TRU-015 and SBI-087 for autoimmune and inflammatory diseases, developed under the company’s Wyeth collaboration. Trubion’s product pipeline also includes Trubion’s proprietary product candidate, TRU-016, a novel CD37-targeted therapy for the treatment of B-cell malignancies that is currently in Phase 1/2 clinical evaluation. In addition to Trubion’s current product candidates, the company is also developing additional alliance and proprietary product candidates that build on its product development experience. More information is available in the investors section of Trubion’s website: investors.trubion.com.

SOURCE: Trubion Pharmaceuticals