8-K

UNITED STATES
SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

Form 8-K

CURRENT REPORT
Pursuant to Section 13 or 15(d) of the
Securities Exchange Act of 1934

Date of Report
(Date of Earliest Event Reported):
September 29, 2010

Trubion Pharmaceuticals, Inc.

(Exact Name of Registrant as Specified in Charter)

Delaware
(State or Other
Jurisdiction
of Incorporation) 001-33054
(Commission File No.) 52-2385898
(IRS Employer
Identification No.)

2401 Fourth Avenue, Suite 1050, Seattle, WA 98121
(Address of Principal Executive Offices, including Zip Code)

(206) 838-0500
(Registrant’s Telephone Number, Including Area Code)

None
(Former Name or Former Address, if Changed Since Last Report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

þ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

o Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

o Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

o Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Item 8.01. Other Events.

On September 29, 2010, Trubion Pharmaceuticals, Inc. (“Trubion”), Emergent BioSolutions Inc. (“Emergent”), and 35406 LLC, a direct wholly-owned subsidiary of Emergent, 30333 Inc., an indirect wholly-owned subsidiary of Emergent entered into an Amendment No. 1 (the “Amendment”) to the Agreement and Plan of Merger entered into by the parties on August 12, 2010, pursuant to which Emergent will acquire Trubion (the “Merger”). Pursuant to the Amendment, Trubion agreed to terminate, effective no later than the effective date of the Merger, its 401(k) plan, as well as any other defined contribution qualified retirement plan maintained by it or an affiliate. Except as so amended, the Merger Agreement remains in full force and effect. This summary is qualified by the full text of the Amendment, which is filed as Exhibit 99.1 hereto and is hereby incorporated by reference.

Additional Information and Where to Find It

This communication is being made in connection with the Merger among Emergent, Trubion and certain of Emergent’s direct and indirect wholly-owned subsidiaries. Emergent has filed with the SEC a registration statement on Form S-4, which contains a prospectus relating to the securities Emergent intends to issue in the proposed Merger. Trubion has filed a definitive proxy statement in connection with the proposed Merger and mailed the definitive proxy statement and other relevant documents to Trubion’s stockholders. Stockholders of Emergent and Trubion and other interested persons are advised to read the registration statement and definitive proxy statement, and amendments thereto because these documents contain important information about Trubion, Emergent and the proposed Merger. The definitive proxy statement was mailed on or about September 27, 2010 to Trubion stockholders of record on September 21, 2010. Stockholders may obtain a copy of the documents filed with the SEC, without charge, at the SEC’s website at http://www.sec.gov or by directing a request to: Emergent BioSolutions Inc., Attn: Investor Relations, 2273 Research Boulevard, Suite 400, Rockville, Maryland 20850, or Trubion Pharmaceuticals, Inc., Attention: Investor Relations, 2401 4th Avenue, Suite 1050, Seattle, Washington, 98121.

Participants in Solicitation

Emergent, Trubion and their respective directors and officers may be deemed participants in the solicitation of proxies from Trubion’s stockholders. Information regarding Emergent’s directors and officers is available in Emergent’s proxy statement for its 2010 annual meeting of stockholders and its 2009 annual report on Form 10-K, which were filed with the SEC and are available at the SEC’s website at http://www.sec.gov. Information regarding Trubion’s directors and officers is available in Trubion’s proxy statement for its 2010 annual meeting of stockholders and its 2009 annual report on Form 10-K, which were filed with the SEC and are available at the SEC’s website at http://www.sec.gov. Information regarding Trubion’s directors and officers is also contained in Trubion’s definitive proxy statement in connection with the Merger which is available at the SEC’s website. Emergent’s and Trubion’s stockholders may obtain additional information about the interests of Trubion’s directors and officers in the Merger by reading Trubion’s definitive proxy statement.

Item 9.01. Financial Statements and Exhibits.

(d) Exhibits.

99.1 Amendment No. 1 to Agreement and Plan of Merger dated September 29, 2010

SIGNATURES

     Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

	TRUBION PHARMACEUTICALS, INC.
Date: September 30, 2010	By:	/s/ John A. Bencich
		Name:	John A. Bencich
		Title:	Vice President and Chief Financial Officer

INDEX TO EXHIBITS

Exhibit No.		Description
	99.1	Amendment No. 1 to Agreement and Plan of Merger dated September 29, 2010

EX-99.1

Exhibit 99.1

Amendment No. 1 to Agreement and Plan of Merger

          This Amendment No. 1 (this “Amendment”) is made and entered into as of September 29, 2010 by and among Emergent BioSolutions Inc. a Delaware corporation (“Parent”), 35406 LLC, a Delaware limited liability company and wholly owned direct subsidiary of Parent (sometimes referred to herein as the “LLC”), 30333 Inc., a Delaware corporation and wholly owned indirect subsidiary of Parent (referred to herein as “Merger Sub”), and Trubion Pharmaceuticals, Inc. a Delaware corporation (the “Company” ), as an amendment to the Agreement and Plan of Merger, dated as of August 12, 2010 (the “Merger Agreement”) by and among Parent, LLC, Merger Sub and the Company.

Recitals

     A. Parent, LLC, Merger Sub and Company are parties to the Merger Agreement. Capitalized terms not defined in this Amendment shall have the meaning given such terms in the Merger Agreement.

     B. Section 7.4 of the Merger Agreement provides that any term or provision of the Merger Agreement may be amended by the parties thereto.

     C. The parties to the Merger Agreement desire to amend Section 5.10(b) thereof, pursuant to the terms of this Amendment.

     In consideration of the foregoing recitals and mutual promises set forth herein, the receipt and sufficiency of which are hereby acknowledged, the parties agree as follows:

     1. Section 5.10(b) of the Merger Agreement is hereby amended in its entirety to read as follows:

     “The Company shall take all actions reasonably necessary to effect the termination of the Company’s 401(k) plan (and any other defined contribution qualified retirement plan maintained by the Company or any ERISA Affiliate), with such termination to be effective no later than the day immediately prior to the Closing Date. The Company’s Board of Directors shall adopt appropriate resolutions authorizing the termination of all such plans and the distribution of plan assets and all necessary attendant actions.”

     2. Except as expressly amended hereby, each term, condition and provision of the Merger Agreement shall remain in full force and effect.

     3. This Amendment may be executed in counterparts, each of which will be an original as regards any party whose name appears thereon and all of which together will constitute one and the same instrument.

[Remainder of Page Intentionally Left Blank]

     In Witness Whereof, the parties have executed this Amendment to the Merger Agreement as of the date first written above.

Trubion Pharmaceuticals, Inc.
By:	/s/ Steve Gillis
Name:	Steve Gillis
Title:	Executive Chairman
35406 LLC
By:  Emergent BioSolutions Inc., its manager
By:	/s/ Daniel Abdun-Nabi
Name:	Daniel Abdun-Nabi
Title:	President
30333 INC.
By:	/s/ Jay Reilly
Name:	Jay Reilly
Title:	Secretary
Emergent BioSolutions Inc.
By:	/s/ Daniel Abdun-Nabi
Name:	Daniel Abdun-Nabi
Title:	President

[Signature Page to Amendment No. 1]

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