OXiGENE Announces Positive Pre-Clinical Results for OXi4503 in Cancer Models; New Data to Be Presented at the American Association for Cancer Research's 95th Annual Meeting.

Business Editors/Health/Medical Writers

WALTHAM, Mass.--(BUSINESS WIRE)--March 29, 2004

OXiGENE, Inc. (NASDAQ: OXGN, XSSE: OXGN) today 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-tumor 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 tumor growth was completely repressed, while doses above 25 mg/kg actually triggered tumor regression."

In another study, researchers concluded that OXi4503 not only shuts down blood flow to tumors, but also might play a direct role in killing tumor 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 tumor cells remained viable. While cell death was evident in skeletal muscle infiltrated by the tumor, "adjacent uninvolved muscle and soft tissue remained viable," researchers said. The compound also caused significant delays in tumor growth.

"The data from these studies is both impressive and encouraging, suggesting that OXi4503 has a distinct mechanism of action and potentially potent anti-tumor 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.

The AACR annual meeting also will include a poster presentation on the effects of several anti-angiogenic and vascular targeting compounds, including OXiGENE's lead VTA, Combretastatin A4 Prodrug (CA4P), in the Ewing's sarcoma family of tumors, and a poster on the pre-clinical compound OXi6197 (NSC D725088).

The poster presentation schedule is as follows:

    8 a.m. - noon
    Monday, March 29
    OXi4503 potentiates the antitumor activity of Carboplatin and
    Paclitaxel
    Klaus Edvardsen, M.D., Ph.D., Lund University

    8 a.m. - noon
    Monday, March 29
    Preclinical studies with dihydronaphthalene monophenol (NSC
    D725087), a vascular targeting agent, and its monophosphate
    prodrug (NSC D725088)
    Hui Wang, Ph.D., University of Alabama at Birmingham

    1 p.m. - 5 p.m.
    Monday, March 29
    Anti-angiogenic and vascular targeting agents delay the growth of
    Ewing's sarcoma family of tumors
    Surita Dalal, Ph.D., St. James's University Hospital

    1 p.m. - 5 p.m.
    Tuesday, March 30
    OXi4503-second generation vascular targeting agent:
    Histopathologic changes and preclinical efficacy
    Amyn M. Rojiani, M.D., Ph.D., University of South Florida

About OXiGENE

OXiGENE is the world leader in the development of vascular targeting agents (VTAs), novel biopharmaceutical compounds designed to selectively target and destroy new blood vessels. The Company's lead compound, Combretastatin A4 Prodrug (CA4P), is in clinical development in patients with solid tumor cancers and wet age-related macular degeneration. Three other OXiGENE VTAs, OXi4503, OXi6197 and OXi8007, are in pre-clinical development. For more information about OXiGENE, visit www.oxigene.com.

Safe Harbor Statement

Statements in this news release concerning the potential pre-clinical efficacy of OXi4503 are "forward-looking statements" within the meaning of the Private Securities Litigation Reform Act of 1995. Any or all of the forward-looking statements in this press release may turn out to be wrong. They can be affected by inaccurate assumptions OXiGENE might make or by known or unknown risks and uncertainties, including, but not limited to: the early stage of product development; the ability to secure necessary patents; uncertainties as to the future success of ongoing and planned clinical trials; and the unproven safety and efficacy of products under development. Consequently, no forward-looking statement can be guaranteed, and actual results may vary materially. Additional information concerning factors that could cause actual results to materially differ from those in the forward-looking statements are contained in OXiGENE's reports to the Securities and Exchange Commission, including OXiGENE's 10-Q, 8-K and 10-K reports. However, OXiGENE undertakes no obligation to publicly update forward-looking statements, whether because of new information, future events or otherwise.