Trubion Pharmaceuticals, Inc. to Present Positive Data From a Phase 2b Re-treatment...

Trubion Pharmaceuticals, Inc. to Present Positive Data From a Phase 2b
Re-treatment Study of TRU-015 at the 2009 EULAR Annual Meeting

SEATTLE, May 18 /PRNewswire-FirstCall/ -- Trubion Pharmaceuticals, Inc.
(Nasdaq: TRBN) announced today that data from the re-treatment portion of a
Phase 2b study (15002) of TRU-015 for rheumatoid arthritis will be presented
on June 11 at the 2009 European League Against Rheumatism (EULAR) annual
meeting in Copenhagen, Denmark. A copy of the abstract is now available at
http://www.eular.org/.

(Logo: http://www.newscom.com/cgi-bin/prnh/20090320/TRUBIONLOGO)

Data from the first course of re-treatment demonstrate that TRU-015 for
rheumatoid arthritis (RA) is well-tolerated and improves the signs and
symptoms of RA as measured by American College of Rheumatology (ACR) response
rates. The Phase 2b trial was designed to evaluate the safety, tolerability,
pharmacodynamics (PD), pharmacokinetics (PK) and clinical activity of repeat
doses of TRU-015. Trubion announced preliminary results from this study in Q4
2008.

TRU-015 is Trubion's lead Small Modular Immunopharmaceutical (SMIP(TM))
product candidate directed against CD20+ B-cells. Wyeth Pharmaceuticals and
Trubion are collaborating on the development of TRU-015 for the treatment of
autoimmune and inflammatory diseases, including RA.

In the initial portion of this double-blind, placebo-controlled, randomized
Phase 2b clinical trial, 276 patients received a single intravenous infusion
of either placebo, 200 mg, 400 mg, 800 mg or 1,600 mg of TRU-015. Of the 276
original patients who began the study, 240 (204 of whom were rheumatoid-factor
positive, or RF+) entered the open-label re-treatment portion of the trial.

At 24 weeks after the first re-treatment, ACR 20, 50 and 70 response rates for
subjects in the group (n=40) that had initially received an 800 mg dose and
were re-treated with 800 mg of TRU-015 were 70%, 40% and 23%, respectively.
ACR 20, 50 and 70 response rates in the group that had received an initial
1,600 mg dose and were subsequently re-treated with 800 mg were 68%, 30% and
14%, respectively. The safety and PD effects after re-treatment were
comparable to those seen after initial therapy.

Numeric reductions in the Disease Activity Score 28 (DAS28), the Health
Assessment Questionnaire (HAQ), and C-reactive protein (CRP) seen at the end
of the double-blind treatment period were maintained or continued to improve
during the open-label re-treatment period.

Infusions were generally well-tolerated and no patient experienced a serious
adverse event on the day of infusion. Eight patients (3%) enrolled in the
trial experienced serious adverse events during the first re-treatment period.
This is similar to observations made during the initial double-blind phase of
the study (placebo 2%, 800 mg group 4%).

"We are encouraged to see such strong results upon re-treatment of trial
participants with TRU-015," said Peter Thompson, M.D., FACP, president, CEO
and chairman of Trubion. "TRU-015 is an important clinical candidate for
Trubion and Wyeth. The positive data we've seen from the program to date
demonstrate that TRU-015 may fill a distinct need for additional treatment
options in the RA community. We look forward to the presentation of the full
re-treatment data at the conference."

The full EULAR presentation will be available in the investor section of
Trubion's website (http://investors.trubion.com/index.cfm) after the
presentation on June 11, 2009.

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 SMIP
therapeutics 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
clinical stage product pipeline, the Company is also developing additional
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/index.cfm.

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 future regulatory filings and
the timing and outcome thereof. 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, and such other risks as identified in the company's
annual report on Form 10-Q for the period ended March 31, 2009, 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 website 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.

TRBN-015RA

Contact:
Jim DeNike
Senior Director, Corporate Communications
Trubion Pharmaceuticals, Inc.
(206) 838-0500
jdenike@trubion.com
http://www.trubion.com

Waggener Edstrom Worldwide Healthcare
Amy Petty
Senior Account Executive
(617) 576-5788
amyp@waggeneredstrom.com

SOURCE Trubion Pharmaceuticals, Inc.

Jim DeNike, Senior Director, Corporate Communications of Trubion
Pharmaceuticals, Inc., +1-206-838-0500, jdenike@trubion.com; or Amy Petty
Senior Account Executive of Waggener Edstrom Worldwide Healthcare,
+1-617-576-5788, amyp@waggeneredstrom.com, for Trubion Pharmaceuticals, Inc.