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 May 2007 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: Acambis wins DE MVA case Acambis wins Delaware MVA case Cambridge, UK and Cambridge, Massachusetts - 16 May 2007 - Acambis plc (Acambis) (LSE: ACM) announces that the Hon. Sue L. Robinson, Chief Judge of the US District Court for the District of Delaware, granted Acambis' motion for summary judgment and dismissed Bavarian Nordic's case in its entirety. This terminates one of the legal actions brought by Bavarian Nordic against Acambis relating to Modified Vaccinia Ankara (MVA). The court ruled that Bavarian Nordic's allegations against Acambis were without basis in law or fact. Bavarian Nordic had claimed that Acambis had improperly obtained and converted the MVA strain that was the basis of its MVA3000 vaccine and engaged in unfair competition and unfair trade practices. The impact of this decision is that the Delaware case has been dismissed in its entirety and that the trial previously scheduled for 5 June 2007 has been cancelled. The court's opinion is publicly available at http://www.ded.uscourts.gov/SLRmain.htm Ian Garland, Chief Executive Officer of Acambis, said: "This decision confirms our position that Acambis did not engage in improper conduct in developing our MVA3000 vaccine. This is the second time we have litigated claims by Bavarian Nordic relating to MVA and the second time that the court has ruled in favour of Acambis." -ends- Enquiries: Acambis plc Ian Garland, Chief Executive Officer Elizabeth Brown, Acting Chief Financial Officer Lyndsay Wright, VP, Communications and IR Tel: +44 (0) 1223 275 300 Brunswick Jon Coles / Justine McIlroy / Margherita Lupi Tel: +44 (0) 20 7404 5959 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. As well as ChimeriVax-JE, 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. Acambis is based in Cambridge, UK and Cambridge, Massachusetts, US, and is listed on the London Stock Exchange (ACM). 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: 16 May 2007 ACAMBIS PLC By: /s/ Lyndsay Wright Name: Lyndsay Wright Title: VP, Communications and IR.