Positive mid-stage data on TroVax in CRC

Oxford BioMedica, a UK gene therapy company, presented encouraging data at the annual meeting of the American Society of Clinical Oncology on  its therapeutic cancer vaccine TroVax, which targets the 5T4 antigen.

In a cross trial analysis of one Phase I/II and three Phase II trials,  survival data were available for 73 colorectal patients, who received a  median of five TroVax vaccinations (range one to six vaccinations). Of  59 immunologically evaluable subjects tested for antibody responses  post-vaccination, 52 (88%) and 56 (95%) showed positive responses for  the 5T4 tumor antigen and the vector system, Modified Vaccinia Ankara,  respectively.

Exploratory analyses demonstrated significant associations between  immune responses and overall survival across the trials.  Cox-proportional hazards modelling (adjusting for age and gender) showed  that a doubling in the 5T4-specific antibody response after the second  and third injections was independently associated with a reduction in  relative risk of death of 14% (p<0.01) and 13% (p=0.01), respectively.  There were no correlations between the immune response to MVA and  patient survival, suggesting that the benefit associated with the 5T4  response is not related to the person's general health status.