Viventia Biotech announces results of Proxinium antibody in combinaton with chemotherapy and radiation

Viventia Biotech has announced results of in vitro cytotoxicity and in vivo pharmacokinetic studies conducted to evaluate the potential for combining its phase III anti-cancer antibody therapeutic, Proxinium, with first-line standard of care therapy for squamous cell carcinoma of the head & neck (SCCHN).

The data were presented at the Annual Meeting of the American Association for Cancer Research (AACR), in Los Angeles, California.

Viventia's lead product, Proxinium, is being developed to treat late stage, locally advanced head and neck cancer and is currently enrolling patients in its TARGET trial, a pivotal Phase III global clinical trial that is expected to complete accrual by the end of 2007. Proxinium targets the cancer antigen EpCAM.

The combination of Proxinium with cisplatin, carboplatin, paclitaxel, 5-fluorouracil, and docetaxel resulted in a significant additive cytotoxic effect (p < 0.05) as compared to the chemotherapeutic agents administered alone. The sequence of drug administration did not influence the outcome. The combination of Proxinium with radiotherapy led to a synergistic cytotoxic effect when Proxinium was administered after radiotherapy or additive effects when Proxinium was administered before or at the same time as radiotherapy.

"The data from these studies clearly demonstrate the additive cytotoxic effect of Proxinium when used either in combination with chemotherapeutic agents or with radiation therapy," said Dr. Barry Wenig, Head of Otolaryngology - Head and Neck Cancer at Evanston Northwestern Healthcare Centre. "These data offer exciting possibilities for the use of Proxinium not solely as a local immunotherapy, but more importantly as an adjunct to the current first-line therapies and even as a precursor to surgery."

Dr. Nick Glover, President and CEO of Viventia Biotech Inc. commented: "Our development strategy for Proxinium is to aggressively pursue initial approval for the treatment of late stage, palliative head and neck cancer, to be followed by a broad clinical program intended to support the addition of Proxinium to standard chemotherapy, radiotherapy and chemoradiotherapy regimens for earlier lines of treatment. These data presented at AACR clearly show the significant promise of adding Proxinium to other treatment modalities in head and neck cancer. Our goal is to establish Proxinium as a key component in the multidisciplinary treatment of this devastating disease."

In vitro cytotoxicity was evaluated pre-, concurrent and post-treatment with Proxinium in SCCHN cell lines CAL 27 and SCC-15. Cell growth inhibition, in combination with various chemotherapeutic agents (cisplatin, carboplatin, paclitaxel, 5-fluorouracil, docetaxel, bleomycin, and methotrexate) was assessed using an MTS assay. Growth inhibition, in combination with radiotherapy, was assessed using a clonogenic assay. In vivo pharmacokinetic profiles generated from drug administration to Sprague-Dawley rats indicated that the pharmacokinetics of cisplatin, paclitaxel, and 5-fluorouracil was not affected when administered in combination with Proxinium. In summary, no antagonism was observed in in vitro or in vivo studies with Proxinium in combination with either chemo- or radiotherapy. The additive and synergistic cytotoxic effects demonstrated in this study indicate the potential utility of Proxinium in conjunction with more conventional treatment modalities for patients with SCCHN and suggest that Proxinium in conjunction with first line standard of care therapy may be of greater benefit than standard care alone.