Oxford BioMedica (LSE: OXB), a leading gene therapy company, today announces encouraging new data from its first Phase II trial of TroVax in prostate cancer. TroVax is Oxford BioMedica’s lead cancer immunotherapy product, which is being developed in collaboration with sanofi-aventis. The Phase II data were presented by the clinical investigators from the Methodist Hospital in Houston, Texas, at the 6th International Symposium on Targeted Anticancer Therapies on 20 March 2008 in Bethesda, Maryland. This event was organised by the NDDO Research Foundation in a partnership with the US National Cancer Institute (NCI; www.cancer.gov) and the European Society for Medical Oncology (ESMO; www.esmo.org).
In the Phase II trial, 27 patients with metastatic hormone-refractory prostate cancer (HRPC) were treated with TroVax alone (n=14) or TroVax in combination with GM-CSF (n=13). TroVax was well tolerated with no related serious adverse events. Eligibility for the trial included patients with progressive disease and pre-treatment with at least one course of chemotherapy. Of 24 evaluable patients, all mounted robust antibody responses against the targeted tumour antigen, 5T4, and nine patients also showed strong 5T4-specific T-cell responses. Twenty patients (83%) experienced disease stabilisation. The duration of disease stabilisation in patients continues to be assessed and currently ranges from two to more than ten months. As in previous trials of TroVax, the anti-tumour immune response induced by TroVax correlated with clinical benefit. Time to disease progression (TTP) was significantly greater in 5T4-specific T-cell responders compared to non-responders, with a median TTP of 5.6 months versus 2.3 months (p = 0.028). The combination of GM-CSF with TroVax showed similar clinical and immunological responses to TroVax alone.
The principal investigator conducting the trial concluded that the high frequency of 5T4-specific immune responses and the correlation with enhanced TTP are encouraging and warrant further investigation. The same clinical team at the Methodist Hospital has initiated a further Phase II trial of TroVax in approximately 60 patients with HRPC. The trial is randomised and is designed to evaluate TroVax in combination with sanofi-aventis’ Taxotere® (docetaxel) as first line therapy versus docetaxel alone. Patients who progress on docetaxel alone will then be treated with TroVax. For more information on this and
other ongoing and planned trials, see www.oxfordbiomedica.co.uk/trovax.htm.
Dr Mike McDonald, Oxford BioMedica’s Chief Medical Officer, commented on the new data: “We continue to be encouraged by the clinical data from ongoing trials of TroVax. It is particularly reassuring to see the relationship between the antigen-specific immune response induced by TroVax and clinical benefit in a third tumour type, following similar conclusions in trials in renal and colorectal cancer. We are delighted that the clinical team at the Methodist Hospital are supporting further development of TroVax in this setting. With our partner, sanofi-aventis, we believe that TroVax could play an important role in the treatment of prostate cancer, addressing a significant unmet need for patients.”