OXiGENE, Inc. announced the presentation of new data showing pre-clinical efficacy of the Company's lead second-generation vascular targeting agent (VTA), OXi4503, in several human cancer models. The results of these studies will be detailed this week in poster presentations at the American Association for Cancer Research's (AACR) 95th Annual Meeting in Orlando, Florida.

Professor Klaus Edvardsen, M.D., Ph.D., of Lund University in Sweden will present a poster on his study evaluating the synergistic effects of OXi4503 with standard-of-care chemotherapy drugs Carboplatin and Paclitaxel in the MDA-MB-231 human breast adenocarcinoma and the ES-2 ovarian carcinoma models grown in mice.

"At doses ranging from 10 to 50mg/kg, OXi4503 significantly enhanced the anti-tumour effects of the chemotherapeutic agents," said Dai Chaplin, Ph.D., OXiGENE's chief scientific officer and head of research and development. "At doses above 10 mg/kg tumour growth was completely repressed, while doses above 25 mg/kg actually triggered tumour regression."

In another study, researchers concluded that OXi4503 not only shuts down blood flow to tumour's, but also might play a direct role in killing tumour cells, suggesting that the VTA could be used as a single agent therapy. Conducted by the University of South Florida in Tampa and the University of Florida in Gainesville, the study measured OXi4503's pre-clinical efficacy and histopathologic effects in rodent KHT and human KSY sarcoma models as well as in a Caki-1 model of human renal cell carcinoma.

Using image analysis, researchers determined that, 24 hours after treatment with a 25 mg/kg dose of OXi4503, less than six percent of the KHT tumour cells remained viable. While cell death was evident in skeletal muscle infiltrated by the tumour, "adjacent uninvolved muscle and soft tissue remained viable," researchers said. The compound also caused significant delays in tumour growth.

"The data from these studies is both impressive and encouraging, suggesting that OXi4503 has a distinct mechanism of action and potentially potent anti-tumour effects," said Fred Driscoll, OXiGENE's president and chief executive officer. "Additional studies are underway to further evaluate OXi4503 in vitro and in vivo, and we are well on the way toward our goal of bringing this compound into the clinic."

Cancer Research UK, the world's largest volunteer-sponsored cancer research organization, is completing pre-clinical toxicology testing on OXi4503 with plans to move the compound into Phase I clinical trials in late 2004.