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Oncothyreon Presents Data from Phase 1/2 Trials of PX-866 in Combination with Docetaxel and with Cetuximab at 2011 AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics

November 13, 2011

SEATTLE, Nov. 13, 2011 /PRNewswire/ – Oncothyreon Inc. (Nasdaq: ONTY) today
announced the presentation of data from two Phase 1/2 trials of PX-866,
an irreversible, pan-isoform phosphatidylinositol-3-kinase (PI-3K)
inhibitor, at the AACR-NCI-EORTC International Conference on Molecular
Targets and Cancer Therapeutics in San Francisco, California. Results
presented highlighted findings from the Phase 1 dose-escalation
portions of Phase 1/2 trials evaluating PX-866 in combination with
docetaxel (Taxotere(®)) and PX-866 in combination with cetuximab (Erbitux®).

PX-866 in Combination with Docetaxel

The Phase 1 portion of the Phase 1/2 trial of PX-866 in combination with
the chemotherapeutic agent docetaxel enrolled 43 patients with advanced
cancer for whom docetaxel was considered standard of care. Patients
were treated at three different dose levels of PX-866 administered
daily in combination with the standard dose of docetaxel (75 mg/m(2)) administered once every three weeks. No dose-limiting toxicities were
identified, and the recommended Phase 2 daily dose of PX-866 to be
given in combination with docetaxel was determined to be the same as
the single agent daily maximum tolerated dose of 8 mg. The combination
of PX-866 and docetaxel was generally well-tolerated, with the most
adverse events being Grade 1/2 in severity. The safety profile for
combination treatment was consistent with that for either drug
administered alone. Combination treatment had no impact on the
pharmacokinetic profile of either drug.

In 28 patients evaluable for response, best response was stable disease
in 21 patients, and progressive disease in seven patients, for a
disease control rate of 75 percent. Eight patients have received seven
or more cycles of treatment, and 20 patients were reported to be still
active on study. The most common reason for discontinuing therapy has
been progressive disease. A trend to increased time on study was seen
in patients with a mutation in their PIK3CA gene compared to patients
without such a mutation.

“Early findings from this trial demonstrate that PX-866 combined with
docetaxel results in a favorable safety profile, with no increase in
toxicities from either drug attributable to the combination, and also
offers encouraging disease control in this patient population,” said
Antonio Jimeno, M.D., Ph.D., of the University of Colorado Cancer
Center, Aurora, Colorado. “We look forward to the continued evaluation
of this combination therapy in the ongoing Phase 2 portion of this
trial.”

This trial has now advanced to Phase 2, which is an open-label,
randomized evaluation of the antitumor activity and safety of PX-866
administered at the recommended daily dose in combination with
docetaxel, versus docetaxel alone, in two groups of patients.  Group 1
is enrolling patients with locally advanced, recurrent or metastatic
non-small lung cancer receiving second or third line treatment.  Group
2 is enrolling patients with locally advanced, recurrent or metastatic
squamous cell carcinoma of the head and neck after failure of prior
therapy. The two groups will be randomized and evaluated independently.
The primary endpoint of the Phase 2 portion is progression free
survival. Secondary endpoints include objective response rate and
overall survival.  Additional information on the trial is available at clinicaltrials.gov.

PX-866 in Combination with Cetuximab

The Phase 1 portion of the Phase 1/2 trial of PX-866 in combination with
cetuximab enrolled 11 patients with either incurable metastatic
colorectal carcinoma or incurable progressive, recurrent or metastatic
squamous cell carcinoma of the head and neck treated at two different
daily dose levels of PX-866 plus the standard weekly dose of cetuximab.
No dose-limiting toxicities were identified and the recommended daily
dose of PX-866 in combination with cetuximab was determined to be the
same as the single agent daily maximum tolerated dose of 8 mg.  The
combination of PX-866 and cetuximab was generally well-tolerated, with
the majority of adverse events Grade 1/2 in severity.  PX-866 had no
impact on the pharmacokinetic profile of cetuximab as compared to
historical data.

Eight patients were evaluable for response per protocol, and four
patients had a confirmed partial response, three patients had stable
disease and one patient had progressive disease, for a disease control
rate of 88 percent. Five of the eight evaluable patients had received
prior treatment with an EGFR inhibitor. Among these patients, the best
response was one partial response, three stable disease and one
progressive disease. The median number of cycles (21 days each)
received by all patients was six (range 1-13).

“The combination of PX-866 and cetuximab demonstrated a favorable safety
profile as well as encouraging objective response rates when compared
to the historical rates for cetuximab alone,” said Diana Hausman, M.D.,
Vice President of Clinical Development for Oncothyreon.

This trial has now advanced to the Phase 2 portion, which is an
open-label, randomized evaluation of the antitumor activity and safety
of PX-866 administered at the recommended daily dose in combination
with cetuximab, versus cetuximab alone, in two groups of patients not
previously treated with cetuximab.  Group 1 is enrolling patients with
metastatic colorectal carcinoma (CRC) who have a history of progression
or recurrence following prior treatment with irinotecan and oxaliplatin
containing regimens or who are intolerant of irinotecan.  Patients with
CRC and Kras mutations are excluded from the trial.  Group 2 is
enrolling patients with incurable squamous cell carcinoma of the head
and neck who have a history of progression or recurrence following at
least one prior platinum based chemotherapy or chemotherapy/radiation
containing regimen.  The two groups will be randomized and evaluated
independently. The primary endpoint of the Phase 2 portion is objective
response rate based on RECIST criteria. Secondary endpoints include
progression free and overall survival, duration of response and disease
control rate.  Additional information on the trial is available at clinicaltrials.gov.

About PX-866

PX-866 is a small molecule, pan inhibitor of the PI-3K/PTEN/AKT pathway,
a critical cell signaling pathway that is activated in many types of
human cancer. Aberrant activation and regulation of PI-3K is implicated
in a large proportion of human cancers, where it leads to increased
proliferation and inhibition of apoptosis (programmed cell death.

Oncothyreon is conducting a broad development program to evaluate PX-866
as a single agent and in combination with other agents in multiple
cancer types. In addition to the randomized Phase 1/2 trials of PX-866
in combination with docetaxel and with cetuximab, the NCIC Clinical
Trials Group is conducting two single-agent Phase 2 trials. These
include a trial in patients with glioblastoma multiforme that has
recurred during or following primary therapy and a trial in patients
with recurrent or metastatic castration-resistant prostate cancer.

About Oncothyreon

Oncothyreon is a biotechnology company specializing in the development
of innovative therapeutic products for the treatment of cancer.
Oncothyreon’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 patients. For more
information, visit www.oncothyreon.com.

Forward Looking Statements

In order to provide Oncothyreon’s investors with an understanding of its
current intentions and future prospects, this release contains
statements that are forward looking, including statements related to
future clinical development plans for our product candidates. These
forward-looking statements represent Oncothyreon’s intentions, plans,
expectations and beliefs and are based on its management’s experience
and assessment of historical and future trends and the application of
key assumptions relating to future events and circumstances.

Forward-looking statements involve risks and uncertainties, including
risks and uncertainties related to Oncothyreon’s business and the
general economic environment. Many of these risks and uncertainties are
beyond Oncothyreon’s control. These risks, uncertainties and other
factors could cause our actual results to differ materially from those
projected in forward-looking statements. Risks, uncertainties, and
assumptions include those predicting the timing, duration and results
of clinical trials, the timing and results of regulatory reviews, the
safety and efficacy of our product candidates, and the indications for
which our product candidates might be developed. There can be no
guarantee that the results of preclinical studies or clinical trials
will be predictive of either safety or efficacy in future clinical
trials. These and other risks and uncertainties are described in the
reports and other documents filed by Oncothyreon Inc. with the SEC
and/or Canadian regulatory authorities.

Although Oncothyreon believes that any forward-looking statements
contained herein are reasonable, it can give no assurance that its
expectations are correct. All forward-looking statements are expressly
qualified in their entirety by this cautionary statement. For a
detailed description of the risks and uncertainties associated with
Oncothyreon, you are encouraged to review the official corporate
documents filed with the securities regulators in the United States on
U.S. EDGAR and in Canada on SEDAR. Oncothyreon is under no obligation
to (and expressly disclaims any such obligation to) update or alter its
forward-looking statements whether as a result of new information,
future events, or otherwise.

SOURCE Oncothyreon Inc.


Source: PR Newswire