Oxford Biomedica Reports TroVax Phase II Trial Results In Renal Cancer

Armen Hareyan's picture

Oxford BioMedica and sanofi-aventis announce new data from two Phase II trials of TroVax in renal 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 Oxford BioMedica and its clinical collaborators from the Methodist Hospital in Houston, Texas, at the 43rd Annual Meeting of the American Society of Clinical Oncology (ASCO) on 3 June in Chicago, Illinois (Abstract #3069).

Fifty-three patients with progressive metastatic renal cell cancer (RCC) have been enrolled and 48 patients are currently evaluable in the Methodist Hospital's two non-randomised Phase II trials of TroVax. The trials are designed to evaluate TroVax either as a single agent, or in combination with either interleukin-2 or interferon-alpha. The treatment regimen in the two trials comprises seven intramuscular injections of TroVax over 41 weeks. The patients had previously failed various anti-cancer treatments before entering the trials.

TroVax was well tolerated with no serious adverse events attributable to the treatment. TroVax induced anti-5T4 antibody responses in 91% of patients. In patients with clear cell RCC, which is the most common subtype of renal cancer and is the patient group for the Phase III TRIST study, 24 of 35 (68%) evaluable patients showed disease control. Two patients had complete responses, three had partial responses and 19 had stable disease for periods exceeding three months, including three patients that have been stable for more than 17 months. Preliminary analysis of clinical benefit shows a statistically significant relationship between reduction in tumour burden (biologic response) in patients with clear cell RCC and patients' anti-5T4 antibody responses (p = 0.028). This is particularly encouraging since it supports the rationale that the 5T4-specific immune response induced by TroVax has therapeutic benefit.

At ASCO, the conclusions presented from this updated analysis of safety, immunogenicity and clinical benefit parameters were as follows:


* TroVax was well tolerated and immunogenic in the context of these cytokines and has promising anti-tumor activity

* A significant number of objective responses have been seen in this heterogeneous group of heavily pre-treated renal cancer patients. These responses appear to be durable and are notable in the clear cell population.

* A preliminary analysis indicates a trend between 5T4-specific immune responses induced by TroVax and clinical benefit in clear cell patients.

* These studies provide further support for the ongoing randomised Phase III TRIST study in renal cancer.

Renal cancer includes renal cell carcinoma (cancer that forms in the lining of very small tubes in the kidney that filter the blood and remove waste products) and renal pelvis carcinoma (cancer that forms in the center of the kidney where urine collects). It also includes Wilms' tumor, which is a type of kidney cancer that usually develops in children under the age of 5. More than 36,600 new cases in the US and 38,400 in Europe were diagnosed in 2004 and almost 12,500 patients in the US and 18,100 patients in Europe died. There were more males than females.

TroVax Oxford BioMedica's leading cancer immunotherapy product, which is being developed in collaboration with sanofi-aventis. It is designed specifically to stimulate an anti-cancer immune response and has potential application in most solid tumour types. TroVax targets the tumor antigen 5T4, which is broadly distributed throughout a wide range of solid tumors. The presence of 5T4 is correlated with poor prognosis. The product consists of a poxvirus (MVA) gene transfer system, which delivers the gene for 5T4 and stimulates a patient's body to produce an anti-5T4 immune response. This immune response destroys tumor cells carrying the 5T4.

In 2006, Oxford BioMedica started a Phase III trial of TroVax in renal cancer and sanofi-aventis is implementing a development plan for colorectal cancer. The product has attracted support from Cancer Research UK, the US National Cancer Institute, and the UK clinical trials network, QUASAR. These organizations are conducting or plan to conduct clinical trials with TroVax.