• 10/27/2004
  • Toronto, Ontario, Canada
  • Press Release
  • Pharmalive.com

Viventia Biotech Inc. today announced the results of the first Phase I clinical study completed with its lead product candidate Proxinium™ for the treatment of advanced, recurrent head and neck cancer. The results, which demonstrate documented tumour responses in several patients, were announced at the Rodman & Renshaw Techvest 6th Annual Healthcare Conference in New York.

The study, which completed enrollment in 8 months, was primarily designed to assess the safety and tolerability of Proxinium™ monotherapy over an escalating dose range. Patients enrolled in this study had advanced head and neck cancer and continuing disease progression, and the majority had failed previous courses of chemotherapy and/or radiotherapy. Preliminary clinical data from the study strongly support the safety profile of Proxinium™, with the observation of mostly mild treatment-related side effects, such as injection site pain.

In addition to positive safety outcomes, Proxinium™ treatment also resulted in several independently verified clinical responses. Of the 24 patients that were dosed in the study, 17 patients expressed the therapeutic target for Proxinium™, from which 14 patients were evaluated for their response to treatment.

Of those 14 patients, two patients experienced significant tumour regressions of their treated lesions and four other patients experienced minor tumour regressions, yielding an objective response rate of 43%. Four other patients had stable disease following Proxinium™ treatment. Tumour growth control (objective responses plus stable disease) was therefore achieved in 71% of treated lesions.

The historical survival rate for advanced, recurrent head and neck cancer patients is approximately 3-5 months. At the conclusion of this study more than half of the patients were still alive, some of whom are approaching 12 months of survival following therapy. Final results are to be published at the American Society of Clinical Oncology annual meeting in May 2005.

These results (43% objective response rate, 71% tumour growth control rate) compare very favourably with recently released Phase II data in advanced, recurrent head and neck cancer using other experimental agents: a) Phase II clinical trial data for cetuximab monotherapy presented at the ASCO conference in June 2004 demonstrated a 12% objective response rate; b) Phase II clinical data for p53 gene therapy presented at the AACR conference in March 2004 demonstrated a 10% objective response rate.

In June 2004, Viventia announced the initiation of a second Phase I clinical study of Proxinium™ for the treatment of head and neck cancer. This ongoing study, which is over 75% enrolled, seeks to define the safety and efficacy of Proxinium™ treatment over a more intensive dosing schedule than that studied in the first Phase I trial. Audited patient outcomes data is not expected until Q1 2005. However, in an interim update Viventia disclosed that objective tumour responses have already been observed in this second study, and reported that at least one patient dosed with Proxinium™ has achieved a complete tumour regression (i.e. complete disappearance of their treated tumour).

Dr. Nick Glover, President and CEO of Viventia, commented: “These results have exceeded our expectations. While we expected Proxinium™ therapy to be safe and well tolerated, as our clinical studies demonstrate, we are extremely encouraged to see such positive indications of Proxinium™’s potential clinical benefit at this early stage of development. Indeed, these observations are quite remarkable given that these clinical studies were not optimized to demonstrate such responses”. Dr. Glover continued: “We designed Proxinium™ to offer a safer and more beneficial therapy for head and neck cancer patients, key attributes that are strongly supported by this positive clinical data. Our strategy remains to aggressively target advanced clinical testing in 2005”.

Dr. Barry Wenig, Professor of Otolaryngology and Head and Neck Surgery, Northwestern University Medical School, and Director of the Division of Head and Neck Surgery, Evanston Northwestern Hospital, Chicago, a clinical adviser to the Company, said: “Patients with advanced, recurrent head and neck cancers, particularly those who have failed radiotherapy or chemotherapy, frequently have limited therapeutic options. Proxinium™ is being developed in a clinical setting that anticipates its potential utility for the local treatment of such cancers. These preliminary data appear very promising in that regard.”