Trubion Announces Initiation Of Phase 2b Study Of TRU 015 For The Treatment Of Rheumatoid Arthritis

Trubion Pharmaceuticals Inc.
(Nasdaq: TRBN) announced that its partner, Wyeth Pharmaceuticals, a
division of Wyeth (NYSE: WYE), has commenced patient dosing in the next
Phase 2b clinical trial of TRU-015 in patients with rheumatoid arthritis
(RA). In collaboration with Trubion, Wyeth Pharmaceuticals is developing
TRU-015, SBI-087 and other CD20-directed products.



The randomized, parallel, double-blind, placebo-controlled, dose
regimen-finding study will evaluate the safety and efficacy of two dosing
regimens 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 American College of
Rheumatology (ACR) 50 response measured at 24 weeks. Secondary outcome
measurements will be ACR 20 and 70 and DAS-28 responses.



"Data reported previously demonstrates TRU-015's ability to
significantly improve RA signs and symptoms, and maintain response rates
with repeat administration of single doses given every six months," said
Peter Thompson, M.D., FACP, president, CEO and chairman of Trubion. "This
study is designed to help us identify an induction, or initial, dosing
regimen and allow us to further establish the most effective treatment
regimen for TRU-015. We believe this study has been designed in a way that
could support a registration package, and we look forward to the results of
this evaluation."



With the addition of SBI-087 -- Trubion's next-generation, fully
humanized CD20-directed SMIPTM -- Trubion's pipeline now includes two
compounds under development for the treatment of autoimmune and
inflammatory diseases. Trubion and Wyeth are leveraging Trubion's SMIPTM
technology to create a portfolio of product candidates with customized
mechanisms of action in an effort to optimize patient safety, efficacy and
convenience.



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.
















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
and the risk that the current Phase 2b study of TRU-015 does not help the
Company and Wyeth identify a TRU-015 induction dosing regimen or further
establish the most effective treatment regimen for TRU-015, 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 Dec. 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 trubion. Trubion undertakes
no duty to update any forward-looking statement to conform the statement to
actual results or changes in the company's expectations.


Trubion Pharmaceuticals Inc.

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