New data may help guide the clinical development of Biomira's PX-478 and PX-866

    EDMONTON, Oct. 24 /CNW/ - Biomira Inc. (Nasdaq:   BIOM) (TSX: BRA)
announced today that preclinical data for its targeted anti-cancer drug
candidates PX-478 and PX-866 were presented in a poster session yesterday at
the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer
Therapeutics, which is being held October 22-26 in San Francisco. The data may
help to guide future clinical studies of these innovative small molecule
compounds. A Phase 1 trial of PX-478 in patients with advanced metastatic
cancers is in progress. Biomira expects to file an Investigational New Drug
application for PX-866 early in 2008.
    The PX-478 data (Abstract No.284) provide insight into how and under what
conditions the compound inhibits the activity of its target, the transcription
factor hypoxia-inducible factor-1alpha (HIF-1 alpha). PX-478 works by a unique
mechanism, decreasing both HIF-1 alpha gene expression and protein synthesis.
This leads to a significant reduction in the amount and activity of HIF-1
alpha in the tumor. The results show that PX-478 is highly specific for HIF-1
alpha and does not inhibit the levels of any of the other proteins tested.
Additionally, this inhibitory effect is independent of the tumor suppressor
genes VHL and p53, genes that may significantly impact how cancer cells
respond to a variety of therapeutic interventions.
    "Hypoxia is a feature of many solid tumors and HIF-1 alpha is the tumor's
primary survival response to this stress," said Dr. Garth Powis, Director,
Center for Targeted Therapy, MD Anderson Cancer Center, Houston, Texas, and
senior author of the abstract. "Inhibiting both transcription and translation
is a double hit that dramatically decreases the activity of HIF-1 alpha, which
regulates numerous pro-cancer pathways. That this reduction in HIF-1a activity
occurs in cells regardless of oxygenation, p53 and VHL status suggests that
PX-478 may have clinical activity in diverse cancers. The elucidation of the
mechanisms by which PX-478 inhibits HIF-1 alpha confirms the compound's
specificity and may aid the direction of the clinical program with respect to
identifying specific cancer indications and potential combination regimens for
this promising agent."
    A second poster reported data from preclinical studies of PX-866, a small
molecule inhibitor of phosphatidylinositol-3-kinase (PI-3 kinase) (Abstract
No.257). These studies evaluated mutations in several cancer-related genes
that could be predictive of response to PX-866 in animal tumor models. In a
range of different tumor types, response to PX-866 correlated with wildtype
Ras, while mutations in Ras were associated with PX-866 resistance. These
results suggest that selecting for patient Ras status could improve the
clinical benefit of PX-866.
    Dr. Powis noted, "Biomarkers that are predictive of response to
particular therapies are playing an increasingly significant role in
optimizing cancer treatment for individual patients. The PX-866 biomarker data
suggest that it may be possible to identify those patients most likely to
respond to the agent. These data also provide insight into how we could
combine PX-866 with other agents based on the molecular profiles of specific
cancers. Together, this knowledge may help to speed the clinical development
of this promising new PI-3 kinase inhibitor"

    Both posters will be available later today on the Biomira website,

    About PX-478

    PX-478 is a potent inhibitor of HIF-1 alpha, a protein target whose
levels are elevated in a wide range of tumors. The protein is a key factor in
the response of a cancer cell to hypoxia (lack of oxygen), including the
angiogenic cascade that allows tumors to establish new blood vessels essential
to their survival and growth. Inhibition of angiogenesis is a validated
approach to treating cancer.
    In preclinical studies, PX-478 demonstrated marked antitumor activity
when delivered orally, showing tumor regression and long growth delay, both of
which correlated to the HIF-1 alpha levels of the tumor models. The wide
variety of models that showed sensitivity to PX-478 presents a large potential
market for this product candidate. The ability to combine PX-478 with
radiation therapy may further expand the opportunities for this novel

    About PX-866

    PX-866 is an irreversible inhibitor of the phosphatidylinositol-3-kinase
(PI3 kinase)/PTEN/AKT pathway, an important survival signaling pathway that is
activated in many types of human cancer especially ovarian, colon, head and
neck, urinary tract, and cervical cancers, where it leads to increased
proliferation, inhibition of apoptosis (programmed cell death) and resistance
to antitumor therapy. In preclinical studies, PX-866 has been shown to induce
prolonged inhibition of tumor PI3 kinase signaling following both oral and
intravenous administration. The compound also has been shown to have good in
vivo anti-tumor activity in tumor models of human colon, pancreatic, breast,
ovarian, prostate and lung cancer, as well as intracranial glioblastoma.

    About Biomira

    Biomira is a biotechnology company specializing in the development of
innovative therapeutic products for the treatment of cancer. Biomira's goal is
to develop and commercialize novel synthetic vaccines and targeted small
molecules that have the potential to improve the lives and outcomes of cancer

    Forward-Looking Statements

    This press release contains forward-looking statements, including,
without limitation, statements related to the pre-clinical and clinical
development of PX-478 and PX-866; the therapeutic and commercial potential of
PX-478 and PX-866; the filing of an investigational new drug application for
PX-866 and the timing thereof; and future clinical development plans. Any
statements contained in this press release that are not statements of
historical fact may be deemed to be forward-looking statements. Words such as
"believes", "anticipates", "plans", "expects", "will", "intends", "potential",
"possible" and similar expressions are intended to identify forward-looking
statements. These forward-looking statements express Biomira's current
expectations, intentions, plans and forecasts of future events based on our
experience and our assessment. Forward-looking statements involve risks and
uncertainties. Various factors could cause actual results to differ materially
from those projected in forward-looking statements, including those predicting
relevance of pre-clinical data to the subsequent clinical development of 
PX-478 and PX-866; the clinical development of PX-478 and PX-866; the
therapeutic and commercial potential of PX-478 and PX-866; the filing of an
investigational new drug application for PX-866 and the timing thereof; and
future clinical development plans. There can be no guarantee that the results
of earlier trials will be predictive of either safety or efficacy in future
trials. Biomira expressly disclaims any obligation or undertaking to release
publicly any updates or revisions to any forward-looking statements contained
herein to reflect any change in the Company's expectations with regard thereto
or any change in events, conditions or circumstances on which any such
statements are based.

For further information:

For further information: Investor and Media Relations Contact: Julie
Rathbun, Rathbun Communications, (206) 769-9219,

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