Allos Therapeutics Receives Orphan Drug Designation From U.S. FDA for EFAPROXYN(TM)

Allos Therapeutics Receives Orphan Drug Designation From U.S. FDA
for EFAPROXYN(TM) 


WESTMINSTER, Colo., Aug. 3  /PRNewswire-FirstCall/ -- Allos Therapeutics
(NASDAQ:ALTH) today announced that the U.S. Food and Drug Administration (FDA)
awarded orphan drug status to the Company's lead clinical candidate,
EFAPROXYN(TM) (efaproxiral) for use as an adjunct to whole brain radiation
therapy (WBRT) for the treatment of brain metastases in patients with breast
cancer.  EFAPROXYN(TM) is currently being investigated in a Phase 3 clinical
trial in this indication at leading cancer centers across North America.

The FDA may award orphan drug designation to drugs that target conditions
affecting 200,000 or fewer U.S. patients per year and provide a significant
therapeutic advantage over existing treatments.  The orphan drug designation
provides for U.S. marketing exclusivity for seven years following marketing
approval by the FDA.  Additionally, the designation qualifies a product for
possible funding to support clinical trials, study design assistance from the
FDA during development and other financial incentives.

"We are pleased to have been awarded the FDA's orphan drug designation for
EFAPROXYN(TM)," said Michael E. Hart, Chief Executive Officer and President of
Allos.  "This designation is a significant milestone in the development of
EFAPROXYN(TM), and, if approved for marketing in this indication, will become
an important component of our commercialization strategy."

In February, Allos initiated a Phase 3, randomized, open-label, multi-center
trial called ENRICH (Enhancing Whole Brain Radiation Therapy (WBRT) In Patients
with Breast Cancer and Hypoxic Brain Metastases) designed to compare the effect
of WBRT with supplemental oxygen with or without EFAPROXYN(TM) in women with
brain metastases from breast cancer.  Results from earlier trials showed a
positive survival benefit and demonstrated a desirable safety profile in this
patient population.  EFAPROXYN(TM) is also currently being evaluated as a
radiation sensitizer in patients with cervical cancer, (Stage IIIA/Stage IIIB)
non-small cell lung cancer (NSCLC) and recurrent glioblastoma multiforme and as
a possible chemo-enhancer enhancer for BCNU (carmustine) chemotherapy for the
treatment of recurrent malignant glioma.

About EFAPROXYN

EFAPROXYN(TM) (efaproxiral) is the first synthetic small molecule designed to
"sensitize" hypoxic (oxygen-deprived) areas of tumors prior to radiation
therapy by facilitating the release of oxygen from hemoglobin, the
oxygen-carrying protein contained within red blood cells, and increasing the
level of oxygen in tumors.  The presence of oxygen in tumors is an essential
element for the effectiveness of radiation therapy in the treatment of cancer.
By increasing tumor oxygenation at the time of treatment, EFAPROXYN(TM) has the
potential to enhance the efficacy of standard radiation therapy.  Unlike
chemotherapeutics or other radiation sensitizers, EFAPROXYN(TM) does not have
to cross the blood brain barrier or enter the tumor to be effective.

About Allos Therapeutics, Inc.

Allos Therapeutics, Inc. is a biopharmaceutical company focused on developing
and commercializing innovative drugs for improving cancer treatments.  The
company's lead clinical candidate, EFAPROXYN(TM), is a synthetic small molecule
that has the potential to sensitize hypoxic (oxygen deprived) tumor tissues and
enhance the efficacy of standard radiation therapy.  In addition, Allos is
developing PDX (pralatrexate), a novel small molecule cytoxic injectable
antifolate (DHFR inhibitor) intended to treat non-small cell lung cancer,
mesothelioma and non-Hodgkin's lymphoma.  For more information, please visit
the company's web site at: http://www.allos.com/.

Safe Harbor Statement

This announcement contains forward-looking statements that involve risks and
uncertainties.  Future events may differ materially from those discussed herein
due to a number of factors, including, but not limited to, risks and
uncertainties related to the Company's ability to adequately demonstrate the
safety and efficacy of EFAPROXYN(TM) for use as an adjunct to WBRT for the
treatment of brain metastases in patients with breast cancer, and to obtain
regulatory approval to market EFAPROXYN(TM) for this indication, as well as
other risks and uncertainties detailed from time to time in the Company's SEC
filings, including its Annual Report on Form 10-K, as amended, for the year
ended December 31, 2003.  Results from earlier clinical trials are not
necessarily predictive of future clinical results.  The company cautions
investors not to place undue reliance on the forward-looking statements
contained in this press release.  Receiving orphan drug designation does not
increase the likelihood of eventual regulatory approval for a product
candidate.  All forward-looking statements are based on information currently
available to the company on the date hereof, and the company assumes no
responsibility to update such statements. 

DATASOURCE: Allos Therapeutics, Inc.



CONTACT:  Jennifer Neiman, Corporate Communications Manager of Allos

Therapeutics, Inc., [phone], ; or Fern Lazar of Lazar

Partners Limited, [phone], , for Allos

Therapeutics, Inc.



Web site:  http://www.allos.com/ 

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