Viventia Biotech to Explore Strategic Alternatives - Reports Positive Pivotal Phase III Interim Efficacy Data

TORONTO, January 29, 2008 /PRNewswire/ - Viventia Biotech Inc., a privately held biopharmaceutical company advancing a portfolio of novel antibody therapeutics focused on cancer, announced today it intends to explore strategic alternatives to further advance and realize value from its pipeline of therapeutic antibodies, its antibody discovery platform and its antibody manufacturing capabilities. The Company will consider potential strategic opportunities including, but not limited to, the sale or merger of the Company with another entity, and has retained HSBC to act as advisors in this process.

The Company also provided an update on the clinical development programs for Proxinium(TM) (Phase 3), Vicinium(TM) (Phase 2) and VB6-845 (Phase 1). Proxinium(TM) is undergoing a global pivotal Phase 3 trial (the 'TARGET' trial) in approximately 300 patients with advanced head and neck cancer. Viventia recently completed an interim efficacy assessment on the study's primary endpoint of median survival. These preliminary results demonstrated a clear survival advantage in the Proxinium(TM) arm.

"We have successfully advanced three antibody programs into clinical trials, and are about twelve months from expected final efficacy data for our pivotal Phase 3 TARGET trial of Proxinium(TM). We believe that our recently performed interim efficacy analysis of survival data from TARGET strongly supports the future prospects for this drug. In addition to our clinical programs, we have generated a broad pipeline from our antibody discovery platform, which has yielded a number of compelling novel targets, including several that have expression profiles consistent with cancer stem cells, an exciting new area of cancer research," said Dr. Nick Glover, President and CEO of Viventia Biotech. "We believe it is important to explore all options to ensure adequate resources are available for the advancement of our products through to commercialization and to further recognize the value of our proprietary discovery platform."

Viventia's late-stage pipeline consists of Armed Antibodies(TM), a novel class of anti-cancer therapeutics that are designed to be safer and more beneficial for cancer patients. These products are fusion proteins comprised of human/humanized monoclonal antibody fragments specific to cancer cell markers, conjugated to highly potent cytotoxic proteins.

Viventia's three lead products target EpCAM, which has recently also been identified as a cancer stem cell marker and is one of the most frequently over-expressed cancer antigens known. A growing body of evidence implicates a functional role for EpCAM in diverse cellular processes such as signaling, cell migration, proliferation, and differentiation. Viventia's clinical portfolio represents one of the most significant anti-EpCAM programs in active development.

Proxinium(TM)

Viventia's lead drug, Proxinium(TM), is a humanized antibody fragment conjugated to the cytotoxic protein Pseudomonas exotoxin A. The drug is in a global pivotal Phase 3 clinical trial (the 'TARGET' trial) in patients with advanced head and neck cancer. Proxinium(TM) has Orphan Drug status in both the U.S. and Europe and has been designated as a Fast Track product by the U.S. FDA.

North American Phase II Update: Viventia recently completed a 15 patient North American Phase 2 clinical trial with Proxinium(TM). Consistent with the Company's previously reported Phase 1/2 clinical trial data, preliminary results from this study continued to demonstrate the relatively benign safety profile of Proxinium(TM) and its potential to improve local disease control in an advanced patient population, with the prospect to impact overall survival.

TARGET Update: TARGET is a randomized Phase 3 trial comparing Proxinium(TM) monotherapy against Best Supportive Care (BSC), and will include approximately 300 patients at more than 110 centers in 18 countries. The trial is currently 50% enrolled, with complete accrual expected in the third quarter of 2008. The Company recently completed an interim efficacy assessment on the study's primary endpoint of median survival based on available preliminary data. This analysis demonstrated an apparent survival advantage in the Proxinium(TM) arm, with approximately a 40% improvement in median survival noted between the curves. Similarly, several Proxinium(TM) patients appear to have achieved durable responses lasting well over 12 months; the expected survival at this stage of disease advancement is typically 4-6 months. The final efficacy assessment for TARGET, based on the primary endpoint of median survival, is expected to be available in the first quarter of 2009.

Vicinium(TM)

Viventia's second late-stage clinical product, Vicinium(TM), is in a Phase 2 clinical study for the treatment of locally recurrent, BCG-refractory non-invasive bladder cancer. The trial will enroll approximately 50 patients, and is being conducted at 19 centers in Canada and the U.S. All patients enrolled in the trial have active, refractory carcinoma in situ, the most aggressive form of non-invasive bladder cancer, and are unresponsive to standard therapy with BCG. In the absence of available options, such patients would typically be considered for radical cystectomy (full surgical removal of the bladder). Viventia believes that Vicinium(TM) may offer a new therapeutic alternative to cystectomy for these patients.

Patients enrolled in the study are receiving either a 6 or 12 week induction treatment, followed by regular maintenance therapy for patients who show a benefit following induction. Currently 29 patients have been enrolled in the trial. Of these, 88% of patients completing induction therapy have qualified for maintenance dosing, with 9 of the first 18 (50%) patients assessed for efficacy demonstrating complete responses (no evidence of disease). None of the patients treated to date have shown disease progression. Vicinium(TM) has demonstrated an excellent safety profile, showing little evidence of side effects, unlike the relatively high toxicity associated with other forms of intravesical therapy, including BCG.

VB6-845

VB6-845 is a humanized antibody fragment targeting EpCAM fused with the Company's proprietary deimmunized form of the cytotoxic protein Bouganin, and is designed for systemic use against metastatic cancers. VB6-845 is currently in a Phase 1 dose escalation trial in patients with solid tumors, which is designed primarily to establish the safety and tolerability of the drug. The study is also structured to provide preliminary evidence of the efficacy of this novel cytotoxic conjugate. Approximately 40-50 patients with an advanced EpCAM-positive epithelial cancer will receive VB6-845 intravenously on a weekly treatment schedule.

The study has currently enrolled 12 patients, with the longest treatment duration being 16 weeks. Encouraging early signs of anti-tumor activity include demonstrable stabilization of disease in several patients, as well as objective signs of tumor responses, and signs of improvement in disease-related sequelae in some patients. Preliminary immunogenicity data reveal anti-Bouganin levels that are either below or near the limit of detection, demonstrating the highly successful deimmunization of the protein.

VB6-845 has demonstrated effective cancer cell killing properties in pre-clinical tests. A full array of animal efficacy studies and safety studies of VB6-845 for the treatment of ovarian cancer and other solid tumors has been completed. In animal xenograft studies, VB6-845 elicited 100% complete cures of established ovarian tumors. VB6-845 has been shown to be safely tolerated in both primate and rodent animal safety studies.

Viventia's antibody and target discovery platform

Viventia has built a proprietary technology platform to discover and advance the next generation of anti-cancer monoclonal antibodies. Viventia's technologies address the fundamental considerations in developing antibody-based therapeutics: 1) choice of target; 2) method of generation; 3) mechanism of action; and 4) production.

    -   Viventia's UnLock(TM) platform isolates and identifies novel

        membrane-associated tumor markers. To date, it has identified 14 new

        potential cancer drug targets. Preliminary proof of concept studies

        performed in animal models of cancer has demonstrated the clinical

        potential of several of these targets. Viventia is actively

        investigating the relationship of some of these targets, including

        CD44E and Glut-8, to cancer stem cells.


    -   Viventia's Fusogenics(TM) platform generates fully human monoclonal

        antibody libraries by leveraging the natural immune response of

        cancer patients and capturing the resulting antibodies in a

        proprietary soluble functional library. Combining both binding and

        functionality, Viventia's Fusogenic(TM) libraries are designed for

        rapid, high-content screening, focused on the assessment of

        therapeutic potential.


    -   Viventia's ImmunoMine(TM) platform is a high-throughput antibody

        screening process that, through increasingly more rigorous tests,

        rapidly sorts therapeutically promising, tumor-specific antibodies

        from antibodies that react with normal cells.


    -   Viventia's Armed Antibody(TM) platform creates novel therapeutics by

        combining the selective targeting properties of antibodies with the

        efficacy of highly potent, tumor-activated payloads.


    -   Viventia's product development is supported by scalable internal cGMP

        manufacturing focused on high-yield microbial production. Viventia's

        process development expertise has facilitated the establishment and

        scale-up of commercially viable manufacturing processes for

        Proxinium(TM) and Vicinium(TM).


    About Viventia Biotech:

Viventia Biotech Inc. is a biopharmaceutical company developing Armed Antibodies(TM), powerful and precise anti-cancer drugs that combine cytotoxic protein payloads with the highly precise tumor-targeting characteristics of monoclonal antibodies to overcome various forms of cancer. Viventia's lead product, Proxinium(TM), is undergoing a global Phase 3 clinical trial for the treatment of head and neck cancer. Viventia is also developing Vicinium(TM), which is in a Phase 3 clinical study for the treatment of bladder cancer, and VB6-845, in Phase 1. The Company has created a portfolio of follow-on antibody-based drug candidates, and has a discovery engine to provide a rich and sustainable long-term pipeline.

CONTACT: For strategic enquiries, please contact: Eugene Rozelman,Investment Banking, HSBC, Tel: (212) 525-4170, Fax: (917) 229-5263, Email:; For further information, please contact: JamesSmith, Tel. (416) 815-0700 x 229, Fax. (416) 815-0080, Email:, www.viventia.com, www.proxinium.com eugene.rozelman@us.hsbc.com jsmith@viventia.com

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Posted: January 2008

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