Filing pursuant to Rule 425 under the
Securities Act of 1933, as amended, and deemed filed pursuant to Rule 14a-12 under the
Securities Exchange Act of 1934, as amended

Filer: Trubion Pharmaceuticals, Inc.
Subject Company: Trubion Pharmaceuticals, Inc.
Commission File No. of Subject Company: 001-33054

Forward-Looking Statements

This communication contains certain forward-looking statements that involve known and unknown risks, delays, uncertainties and other factors not under the control of Trubion. The company’s actual results, performance or achievements could be materially different from those projected by these forward-looking statements. The factors that could cause actual results, performance or achievements to differ from the forward-looking statements include the risk that the acquisition of Trubion by Emergent may not be consummated for reasons including that the conditions precedent to the completion of the acquisition may not be satisfied; the risk that one or more the milestones that would give rise to CVR payments is not achieved; the possibility that the expected benefits from the proposed merger will not be realized, or will not be realized within the anticipated time period; the risk that Emergent and Trubion’s businesses will not be integrated successfully; the possibility of disruption from the merger making it more difficult to maintain business and operational relationships; any actions taken by either of the companies, including, but not limited to, restructuring or strategic initiatives (including capital investments or asset acquisitions or dispositions); and other risks that are discussed in Trubion’s filings with the SEC, such as its Form 10-K, 10-Q and 8-K reports. Given these risks and uncertainties, you are cautioned not to place undue reliance on the forward-looking statements.

Additional Information about the Transaction and Where to Find It

This communication shall not constitute an offer to purchase or a solicitation of an offer to sell securities. In connection with this transaction, Emergent intends to file with the Securities and Exchange Commission (SEC) a registration statement on Form S-4 and Trubion intends to file with the SEC and mail to its stockholders a proxy statement/prospectus. Investors and stockholders are urged to read the registration statement, the proxy statement/prospectus and other relevant documents filed with the SEC when they become available, as well as any amendments or supplements to the documents because they will contain important information about Emergent, Trubion and the transaction.

The registration statement, the proxy statement/prospectus and any other relevant materials (when they become available), and any other documents filed by Emergent and/or Trubion with the SEC, may be obtained free of charge at the SEC’s web site at www.sec.gov. In addition, investors and stockholders may obtain free copies of the documents filed with the SEC by directing a written request to: Emergent BioSolutions Inc., Attn: Investor Relations, 2273 Research Blvd., Suite 400, Rockville, MD 20850, or Trubion Pharmaceuticals Inc., Attn: Investor Relations, 2401 4th Ave., Suite 1050, Seattle, WA 98121. Investors and stockholders are urged to read the registration statement, the proxy statement/prospectus and the other relevant materials when they become available.

Participants in Solicitations

Emergent, Trubion and their respective directors, executive officers and other members of their management and employees may be deemed to be participants in the solicitation of proxies from stockholders of Trubion in connection with the merger. Information regarding Emergent’s directors and officers is available in Emergent’s proxy statement on Schedule 14A for its 2010 annual meeting of stockholders, which was filed with the SEC on April 9, 2010. Information regarding Trubion’s directors and executive officers is available in Trubion’s proxy statement on Schedule 14A for its 2010 annual meeting of stockholders, which was filed with the SEC on April 21, 2010. Additional information regarding the interests of such potential participants will be included in the proxy statement and the other relevant documents filed with the SEC when they become available.

The following is a transcript of the investor meeting held by Trubion on August 12, 2010 to discuss the proposed merger transaction with Emergent.

TRUBION PHARMACEUTICALS, INC.

Moderator: Jim DeNike
August 12, 2010
2:00 p.m. PST

Operator:	Good day, ladies and gentlemen, and welcome to the Trubion conference call. At this time, all participants are in listen-only mode. Later, we will conduct a question-and-answer session, and instructions will follow at that time. If you should need operator assistance during the conference, please press star, then zero on your touchtone telephone. As a reminder, this conference is being recorded.
	I would now like to introduce your host for today’s conference, Mr. Jim DeNike.
	Sir, you may begin the call.
Jim DeNike:	Thanks, (James). And thanks, everyone, for joining us today.
	On the call from Trubion is Dr. Steven Gillis, our executive chairman and acting president, Dr. Scott Stromatt, our chief medical officer, Dr. Ken Mohler, our chief scientific officer, Michelle Burris, our chief operating officer, and John Bencich, our chief financial officer.
	Earlier today, we issued a press release announcing our agreement to be acquired by Emergent BioSolutions. And a copy of that release can be found on our Web site at trubion.com.
	I’d like to remind each of you that today’s conference call may contain forward-looking statements based on our current expectations. These statements are only predictions, and actual results may materially vary from those projected. Please refer to Trubion’s documents filed with the SEC concerning factors that could affect the company, copies of which are also available on our Web site.
	I will now turn the call over to Steve.
Steven Gillis:	Thank you, Jim. And thanks to all of you for joining us today.
	As Jim mentioned, earlier today we announced the signing of a definitive merger agreement with Emergent BioSolutions, in which Emergent has agreed to acquire Trubion. I’ll take a

few minutes to review the terms of the agreement and why we believe this agreement will provide both near- and long-term value to our employees and our stockholders.

Following the conclusion of my remarks, we will invite your questions.

First, I’ll take a few minutes to go over the terms of the agreement as outlined in the press release. At closing of the transaction, each outstanding share of Trubion common stock will be converted into an upfront payment of $1.365 per share in cash and 0.1641 shares of Emergent BioSolutions common stock. The upfront payment represents a value of $4.55 per share, or approximately $96.8 million, based on Trubion’s total common shares outstanding, the net value of dilutive stock options, and the trading average of Emergent BioSolutions common stock for the five days prior to the signing of the definitive agreement.

Trubion Pharmaceuticals stockholders will also receive one contingent value right per share, which will entitle the holder to receive cash payments based upon achievement of the following milestones.

Initiation of the first Phase 2 clinical study for TRU-016, $1.75 million. Release of TRU-016 manufactured for use in clinical studies, $10 million. Initiation of dosing in the first Phase 2 clinical study for a non-CD20 target, $0.75 million.

Initiation of the first Phase 3 clinical study in an oncology indication for TRU-016, $15 million. Initiation of dosing in the first Phase 3 clinical study for the first major indication for CD20 candidate, $6.25 million. Initiation of dosing in the first Phase 3 clinical study for the second major indication for CD20 candidate, $5 million.

The total potential aggregate value of the CVRs is $38.7 million, or $1.75 per share, over a 36-month period, post-closing. The combination of the upfront consideration along with the potential value of the CVRs results in total consideration of up to $135.5 million for Trubion stockholders.

We are very pleased that Emergent intends to maintain our research and development laboratories and offices in Seattle upon completion of the acquisition and that our location will become a therapeutics-focused product-development site for the combined company.

We believe the combination of Emergent’s strong financial position and expertise and development of biologics with Trubion’s innovative SMIP and SCORPION protein

	therapeutic product candidates and technologies will accelerate the continued development of these promising products and technologies.
	We look forward to working diligently in the coming months to ensure continued development of Trubion’s clinical stage assets, as well as completion of additional pre-clinical experimentation, to further validate Trubion’s product development candidates as being worthy of progression toward clinical trials.
	The transaction has been approved by the boards of directors of both companies and is subject to customary closing conditions, including the approval of the acquisition by stockholders of Trubion and the expiration or termination of the applicable waiting period under the Hart-Scott-Rodino Antitrust Improvements Act of 1976.
	Additional details related to the merger agreement, including the location and timing of a special meeting of stockholders, will be included in the proxy statement, which we expect to file with the SEC and mail to Trubion stockholders in the coming weeks. The acquisition of Trubion is expected to close in the fourth quarter of 2010.
	In the meantime, Trubion and its employees will continue to pursue its corporate objectives and product and collaboration milestones.
	That concludes my opening remarks. I’d like to thank each of you for your ongoing interest in Trubion. And now we’ll ask the operator to open the call for questions.
Operator:	Thank you. If you have a question at this time, please press star, then one on your touchtone telephone. If your question has been answered or you wish to remove yourself from the queue for any reason, please press the pound key. Again, if you have a question, please press star, then one.
	I’m showing no questions at this time.
Jim DeNike:	OK, thanks, (James). We’d like to thank everybody for dialing in, and we look forward to giving you an update as we progress. Thanks again.
Operator:	Thank you. Ladies and gentlemen, thank you for participating in today’s conference. This does conclude the program. You may now disconnect.

END