Oxford BioMedica, a leading gene therapy company, announced that the independent Data Safety Monitoring Board (DSMB) for the phase III TRIST study of TroVax in renal cancer has recommended that the trial should continue but that further vaccinations be discontinued. TroVax is Oxford BioMedica's novel therapeutic cancer vaccine, which is being developed in collaboration with sanofi-aventis.

Following its fourth interim review of the TRIST study, the DSMB advised that TroVax administered according to the protocol will not meet the predefined primary efficacy endpoint, but there is important scientific merit and more to be learned by additional follow up of all patients. Hence, the DSMB's recommendation is to continue the study but discontinue further vaccinations. Oxford BioMedica has implemented the DSMB's recommendation. In addition, the company intends to amend the statistical plan of the study to determine whether patient outcome is dependent on the number of TroVax doses administered.

Oxford BioMedica and, its partner, sanofi-aventis, will evaluate the available data and the implications on the development plan for TroVax, including the planned Phase III trials in colorectal cancer. The companies will discuss the proposed TRIST protocol amendments with the regulatory authorities. With these amendments, a focus of the ongoing TRIST study will be to explore the number of doses that provide optimal benefit. In particular, it may be that the optimal benefit-to-risk ratio is delivered without the requirement for as many vaccinations as specified in the original TRIST study protocol. It is unlikely that the TRIST study alone will support registration of TroVax in renal cancer, although the trial may ultimately demonstrate a survival advantage for TroVax, and the results may form part of a regulatory submission alongside an additional confirmatory trial.

The role of the DSMB is to monitor, periodically, the data emerging from the study to determine whether there are issues arising that would warrant modification of the protocol or early termination of the study. The DSMB is independent of Oxford BioMedica and sanofiaventis.

The TRIST (TroVax Renal Immunotherapy Survival Trial) study is a randomised and placebo controlled Phase III trial, designed to evaluate TroVax in combination with standard of care in locally advanced or metastatic clear cell renal carcinoma. The trial was initiated in November 2006 and completed recruitment of 733 patients in March 2008 in more than 100 sites in the USA, European Union and Eastern Europe. The original trial protocol, which was the subject of a Special Protocol Assessment by the US Food and Drug Administration (FDA), allowed for patients to receive up to 13 immunisations over 73 weeks.

Dr Mike McDonald, chief executive of Oxford BioMedica, said: "This news is clearly disappointing. However, there is good reason to continue the study and potentially a late survival benefit for TroVax may still be demonstrated. The proposed trial amendment will assess whether the maximum benefit-to-risk ratio is dependent on an optimal number of doses. We remain optimistic that TroVax may show benefit in this population after these protocol amendments. With our partner, sanofi-aventis, we will provide an update on the TRIST study and the development plan for TroVax in due course."

Dr McDonald added: "In addition to TroVax, we have a broad pipeline of innovative drug candidates and we will continue to focus our resources on deriving maximum value for both patients and shareholders, while maintaining the Company's financial strength. In particular, we look forward to reporting initial results from the Phase I/II trial of ProSavin in Parkinson's disease in September. In addition, we are working diligently towards the start of clinical trials of RetinoStat in neovascular age-related macular degeneration."

Oxford BioMedica is a biopharmaceutical company specialising in cancer immunotherapy and gene-based therapies. The company was established in 1995, as a spin-out from Oxford University, and is listed on the London Stock Exchange.

TroVax is the company's therapeutic vaccine, which is in clinical development for multiple solid cancers. The product is licensed to sanofi-aventis for global development and commercialisation. Oxford BioMedica has three other products in clinical development, including ProSavin, a novel gene-based treatment for Parkinson's disease, in a Phase I/II trial. The Company is underpinned by over 80 patent families, which represent one of the broadest patent estates in the field.