First Patient Dosed in Phase 1 Trial of SBI-087, Trubion’s Next-Generation Candidate

SEATTLE, WA, USA | April 21, 2008 | Trubion Pharmaceuticals Inc. (Nasdaq: TRBN) today announced that its collaboration partner Wyeth Pharmaceuticals, a division of Wyeth (NYSE: WYE), has initiated a Phase 1 clinical trial of SBI-087, a next-generation drug candidate for the treatment of rheumatoid arthritis (RA). In collaboration with Trubion, Wyeth Pharmaceuticals is developing SBI-087 and other CD20-directed products. SBI-087 for RA builds on Trubion and Wyeth’s clinical experience with Trubion’s lead compound, TRU-015, and is based on Trubion’s Small Modular ImmunoPharmaceutical (SMIP(TM)) technology.

The Phase 1 SBI-087 dose escalation clinical trial is designed to evaluate the safety, tolerability, pharmacokinetics and pharmacodynamics of a single dose of SBI-087 in patients with RA. Preclinical research suggests that SBI-087, a fully humanized CD20-directed SMIP, has enhanced potency in B-cell depletion in vivo compared with Rituxan. This Phase 1 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.

With SBI-087, Trubion’s pipeline now includes two differentiated compounds under development for the treatment of autoimmune and inflammatory diseases: TRU-015 and SBI-087. Trubion and Wyeth are leveraging Trubion’s SMIP(TM) technology to create a portfolio of product candidates with customized mechanisms of action in an effort to optimize patient safety, efficacy and convenience.

"Initiation of the SBI-087 Phase 1 clinical trial marks an important milestone in advancing our pipeline through our collaboration with Wyeth," said Peter Thompson, M.D., FACP, president, CEO and chairman of Trubion. "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."

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 proprietary product candidate, TRU-016, is a novel CD37-targeted therapy for the treatment of B-cell malignancies 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: http://investors.trubion.com.

Forward-Looking Statements

Certain statements in this release may constitute "forward-looking statements" within the meaning of Section 21E of the Securities Exchange Act of 1934 and Section 27A of the Securities Act of 1933. These statements include, but are not limited to, those related to the company’s future clinical development programs and the timing thereof, the company’s expected financial and operating results, future clinical development plans, the details of the clinical trials and the results and timing thereof, and the timing of regulatory applications and action. These statements are based on current expectations and assumptions regarding future events and business performance and involve certain risks and uncertainties that could cause actual results to differ materially. These risks include, but are not limited to, risks associated with the company’s Wyeth collaboration, including Wyeth’s control over development timelines, the risks that the Company is unable to advance its clinical development programs and regulatory applications and action at the rate it expects, the risk that the Company does not achieve the financial and operating results it expects and such other risks as identified in the company’s quarterly report on Form 10-K for the period ended December 31, 2007, and from time to time in other reports filed by Trubion with the U.S. Securities and Exchange Commission. These reports are available on the Investors page of the company’s corporate Web site at http://www.trubion.com. Trubion undertakes no duty to update any forward-looking statement to conform the statement to actual results or changes in the company’s expectations.

 

SOURCE: Trubion Pharmaceuticals Inc.