OXiGENE Reports Preclinical Data for OXi4503 Showing Pronounced Antitumor Activity in Animal Studies in Acute Myeloid Leukemia

OXiGENE Reports Preclinical Data for OXi4503 Showing Pronounced Antitumor
Activity in Animal Studies in Acute Myeloid Leukemia At the American
Association of Cancer Research Annual Meeting 

WALTHAM, Mass., April 22, 2009 (GLOBE NEWSWIRE) -- OXiGENE, Inc. (Nasdaq:OXGN)
(XSSE:OXGN), a clinical-stage, biopharmaceutical company developing novel
therapeutics to treat cancer and eye diseases, reported data showing that
OXi4503 has pronounced antitumor activity when administered as a single agent
or in combination with chemotherapy in acute myelogenous leukemia (AML)
xenograft models. In the studies, NOD-SCID mice bearing established HL60
xenografts were treated with a series of doses and regimens of either OXi4503
or fosbretabulin administered either as single agents, or combined with araC
(standard AML chemotherapy) and evaluated for signs of activity. Results showed
that the antitumor activity of OXi4503 against HL60 xenografts is superior to
that observed for fosbretabulin, and that HL60 AML xenografts are sensitive to
OXi4503 administered as a single agent. In addition, the combination of OXi4503
with araC increased antitumor activity with no apparent increase in toxicity. 

"These results add to previously published data obtained with fosbretabulin
which demonstrate in an animal study significant single-agent anti-leukemic
action of OXiGENE's VDAs. We believe, based on the data available to date, that
the anti-leukemic action is mediated through multiple mechanisms, including
direct cytotoxicity and vascular disruption. More importantly, in the case of
orthotopic leukemia models, the compound's activity may be related to release
of treatment-resistant leukemic cells from stromal niches via disruption of
VLA4-VCAM1 interactions," commented David Chaplin, Ph.D., Chief Scientific
Officer at OXiGENE. "We believe that these results are particularly exciting as
they demonstrate that OXi4503 may have potential as a single-agent therapy for
certain leukemias." 

OXiGENE anticipates that further corroborative OXi4503 preclinical data in AML
obtained by OXiGENE's collaborators will be presented at a future scientific
meeting. The company is currently assessing its options for clinically
evaluating OXi4503 as a potential treatment for patients with AML. 

About OXi4503

OXi4503 (combretastatin A1 di-phosphate / CA1P) is a dual-mechanism vascular
disrupting agent (VDA) that is being developed in clinical studies for the
treatment of solid tumors. Like its structural analog, ZYBRESTAT(TM)
(fosbretabulin / CA4P), OXi4503 has been observed to block and destroy tumor
vasculature, resulting in -- more -- extensive tumor cell death and necrosis.
In addition, preclinical data indicate that OXi4503 is metabolized by oxidative
enzymes (e.g., tyrosinase and peroxidases), which are elevated in many solid
tumors and tumor white blood cell infiltrates, to an orthoquinone chemical
species that has direct cytotoxic effects on tumor cells. Preclinical studies
have shown that OXi4503 has (i) single-agent activity against a range of
xenograft tumor models; and (ii) synergistic or additive effects when
incorporated in various combination regimens with chemotherapy,
molecularly-targeted therapies (including tumor-angiogenesis inhibitors), and
radiation therapy. OXi4503 is currently being evaluated as a monotherapy in a
Phase 1 dose-escalation study in patients with advanced solid tumors. OXiGENE
is developing OXi4503 under the strategic drug development partnership it
established with Symphony Capital in October 2008. 

About OXiGENE

OXiGENE is a clinical-stage biopharmaceutical company developing novel
therapeutics to treat cancer and eye diseases. The company's major focus is
developing VDAs that selectively disrupt abnormal blood vessels associated with
solid tumor progression and visual impairment. OXiGENE is dedicated to
leveraging its intellectual property and therapeutic development expertise to
bring life-extending and -enhancing medicines to patients. 

The OXiGENE, Inc. logo is available at
http://www.globenewswire.com/newsroom/prs/?pkgid=4969 

Safe Harbor Statement

This news release contains "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.
Forward-looking statements can be affected by inaccurate assumptions OXiGENE
might make or by known or unknown risks and uncertainties, including, but not
limited to, mechanisms of anti-leukemic action of OXi4503, the potential of
OXi4503 as a single-agent therapy for certain leukemias and publication of
further corroborative OXi4503 preclinical data in AML obtained by OXiGENE's
collaborators. Additional information concerning factors that could cause
actual results to materially differ from those in the forward-looking
statements is contained in OXiGENE's reports to the Securities and Exchange
Commission, including OXiGENE's reports on Form 10-K, 10-Q and 8-K. However,
OXiGENE undertakes no obligation to publicly update forward-looking statements,
whether because of new information, future events or otherwise. Please refer to
our Annual Report on Form 10-K for the fiscal year ended December 31, 2008. 

CONTACT:  OXiGENE, Inc.
          Investor Relations
          Michelle Edwards
          415-315-9413
          medwards@oxigene.com