FORM 6-K SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Report of Foreign Private Issuer Pursuant to Rule 13s - 16 or 15d - 16 of the Securities Exchange Act of 1934 For the month of November 2006 Acambis plc (Translation of registrant's name into English) Peterhouse Technology Park 100 Fulbourn Road Cambridge CB1 9PT England (address of principal executive offices) (Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F Forms 20-F X Form 40-F Indicate by check mark whether the registrant by furnishing the information contained in this Form also thereby furnishing the information to the Commission pursuant to Rule 12g3-2(b) under the Securities Exchange Act of 1934). Yes No X (if "Yes" is marked, indicate below the file number assigned to the registrant in connection with Rule 12g3-2(b): 82- ). Enclosure: Update on US MVA procurement Update on US Government MVA procurement Cambridge, UK and Cambridge, Massachusetts - 14 November 2006 - Acambis plc ("Acambis") (LSE: ACM; NASDAQ: ACAM) announces that it has received notification from the US Department of Health and Human Services ("HHS") that its proposal is no longer being considered for award as part of the US Government's Modified Vaccinia Ankara ("MVA") smallpox vaccine tender process. Acambis received notification late yesterday that HHS has re-evaluated Acambis' technical proposal and found that its proposal is no longer in the competitive range for award. As such, Acambis is no longer eligible to receive a contract. Acambis plans to request a meeting to gain further clarification, following which it will consider its options. The US National Institutes of Health has indicated that it intends to continue Acambis' existing MVA contracts at their current price and scope. Gordon Cameron, Chief Executive Officer, said: "We are surprised that the US Government would eliminate Acambis from the RFP process. We believe that our proposal would have met the requirements of the US Government, especially given Acambis' track record in the biodefence field." -ends- Enquiries: Acambis plc Lyndsay Wright, VP, Communications and IR Tel: +44 (0) 1223 275 300 Financial Dynamics David Yates/Anna Keeble Tel: +44 (0) 20 7831 3113 About Acambis Acambis is a leading biotechnology company targeting infectious diseases with novel vaccines. Acambis' development-stage pipeline includes vaccines that could either offer improvements over existing products or target unmet medical needs. Its investigational vaccine against Japanese encephalitis, ChimeriVax-JE, which is undergoing Phase 3 clinical testing, is intended to provide an "ideal" vaccine to address the estimated 50,000 cases of this viral disease in Asia every year. Acambis' proprietary ChimeriVax technology, developed in association with St Louis University, has also been used to develop ChimeriVax-West Nile, which is undergoing Phase 2 clinical testing, making it the most advanced investigational vaccine against the West Nile virus. Acambis also has the only vaccine in development against Clostridium difficile bacteria, a leading cause of hospital-acquired infections. Recognised internationally as the leading producer of smallpox vaccines, Acambis is developing an investigational smallpox vaccine, ACAM2000, and is manufacturing emergency-use stockpiles of this investigational vaccine for the US Government and other governments around the world. It is also developing an attenuated smallpox vaccine, MVA3000, under contracts with the US National Institutes of Health. Acambis is based in Cambridge, UK and Cambridge, Massachusetts, US, and is listed on the London Stock Exchange (ACM). Its shares are listed on NASDAQ (ACAM) in the form of American Depositary Receipts. More information is available at www.acambis.com. "Safe Harbor" statement under the Private Securities Litigation Reform Act of 1995: The statements in this news release that are not historical facts are forward-looking statements that involve risks and uncertainties, including the timing and results of clinical trials, product development, manufacturing and commercialisation risks, the risks of satisfying the regulatory approval process in a timely manner, the need for and the availability of additional capital. For a discussion of these and other risks and uncertainties see "Risk management" in the Company's 2005 Annual Report and "Risk factors" in its Form 20-F, in addition to those detailed on the Company's website and in the Company's filings made with the Securities and Exchange Commission from time to time. These forward-looking statements are based on estimates and assumptions made by the management of Acambis and are believed to be reasonable, though are inherently uncertain and difficult to predict. Actual results or experience could differ materially from the forward-looking statements. SIGNATURE Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant Peptide Therapeutics Group has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized. Date: 14 November 2006 ACAMBIS PLC By: /s/ Lyndsay Wright Name: Lyndsay Wright Title: VP, Communications and IR.