Press release
BioVex to report Phase II clinical trial results of OncoVEXGM-CSF in metastatic melanoma at the 2008 American Society of Clinical Oncology Meeting

Woburn, MA, May 16, 2008 – BioVex Inc, a biotechnology company developing clinical stage products in oncology and infectious disease, announced today that the abstract describing the interim results from its Phase II clinical trial of OncoVEXGM-CSF in advanced metastatic melanoma is now available at the American Society of Clinical Oncology (ASCO) website located at http://www.asco.org. A summary of the abstract which describes the data as of the submission date to ASCO in January 2008 is provided below.

Senior clinical investigator, Neil N. Senzer, M.D., will present up-to-date results of the abstract entitled “Phase II clinical trial with a second generation, GM-CSF encoding, oncolytic herpes virus in unresectable metastatic melanoma,” at the 2008 ASCO Annual Meeting in Chicago, IL on Sunday, June 1 at 9:30am EDT during the melanoma conference session.

A summary of the abstract follows:

Background: OncoVEXGM-CSF is a second generation oncolytic herpes simplex virus (HSV) which encodes GM-CSF. OncoVEXGM-CSF had previously been shown to be well tolerated in a phase I clinical trial in patients with a range of tumor types, in which anti-tumor effects were seen in both injected and un-injected tumors.

Phase II Study Design: Single-arm monotherapy in up to 50 patients with unresectable stage IIIc/IV metastatic melanoma.

End Points: The trial was designed to measure overall objective response, which is defined as a complete response, where disease is completely eliminated, or partial response, where there is a >30% reduction in disease burden. The target efficacy endpoint detailed in the Phase II protocol and agreed upon with the FDA was to achieve two objective responses or stable disease >2months.

Interim Results: At the time of the abstract submission, 40 patients had been enrolled of whom 31 were evaluable. 81% had stage IV disease. With respect to systemic objective overall responses; three complete responses (CR), three partial responses (PR) and two mixed responses (≥PR of existing disease and ≥PR of lesions which became measurable after initiation of therapy) were reported. Two further patients had post treatment objective responses and four patients had durable stable disease. All objective responses were ongoing at between four and 23 months following the patient’s first dose of OncoVEXGM-CSF. Side effects were reported to be largely limited to mild flu-like symptoms, as expected from the Phase I study.

Abstract Conclusion: An impressive rate and durability of response had been observed in this interim dataset as compared to the other limited treatment options available to patients with advanced melanoma.

BioVex President and CEO Philip Astley-Sparke commented:

“Based on the data described above, the Company recently reached agreement with the FDA for a pivotal Phase III study under the Special Protocol Assessment (SPA) procedure, with a response rate-based primary endpoint. We look forward to Dr Senzer’s presentation on an up-to-date expanded data set at ASCO on June 1st.”

About Metastatic Melanoma

According to the American Cancer Society, more than 8,000 people died in the U.S. of melanoma in 2007. Prevalence of stage III and stage IV disease is 120,000 and median survival for Stage IV disease is six months.

Treatment of melanoma depends on the stage of the disease with surgical resection being effective in less severe non metastatic forms of the disease. However, survival rates for later Stage III and IV patients are poor, reflecting the lack of any efficacious drugs for metastatic disease. Current systemic therapies are not generally effective in terms of generating durable responses or in impacting survival. As a result, many patients presenting with metastatic disease are directly enrolled into a clinical trial. The vast majority of experimental therapies have failed to show more than a single digit response rate.

About BioVex

BioVex is a privately held biotechnology Company based in Woburn. MA. The Company is developing a new class of potent biologics for the treatment of cancer and prevention of infectious disease.

The Company’s lead cancer technology platform, OncoVEXGM-CSF, is an unpartnered, first-in-class oncolytic, or cancer destroying virus technology. OncoVEXGM-CSF works by: 1) replicating and spreading within solid tumors, causing the death of cancer cells; while 2) stimulating the immune system to destroy metastatic deposits. Both modes of action have been clearly validated in the clinic, where multiple patients with metastatic disease progressing at enrollment have been declared disease free. BioVex believes OncoVEXGM-CSF has the potential to become a leading standard of care in the treatment of many solid tumors based on the strength of clinical data generated to date, coupled with a benign side effect profile.

BioVex is currently completing a Phase II clinical trial of OncoVEXGM-CSF for melanoma and Phase I/II clinical trials for head & neck cancer and pancreatic cancer. The Company recently announced that the FDA has approved the design of a single, pivotal Phase III clinical trial evaluating OncoVEXGM-CSF in previously treated patients with metastatic melanoma under the Special Protocol Assessment (SPA) procedure and plans to make a second SPA submission for head & neck cancer later in the year.

The Company's second program is a vaccine for genital herpes, ImmunoVEXHSV2, which provides complete protection in animal models of the disease. A Phase I study with ImmunoVEXHSV2 is scheduled to commence in the third quarter of 2008.