FDA Advisory Committee Does Not Recommend Approval of RSR13 as Adjunctive Therapy for the Treatment of Brain Metastases Originat

FDA Advisory Committee Does Not Recommend Approval of RSR13 as
Adjunctive Therapy for the Treatment of Brain Metastases Originating From
Breast Cancer 


WESTMINSTER, Colo., May 3  /PRNewswire-FirstCall/ -- Allos Therapeutics, Inc. 
announced today that the U.S. Food and Drug Administration (FDA) Oncologic
Drugs Advisory Committee (ODAC) did not recommend approval of the company's
investigational radiation sensitizer RSR13 (efaproxiral) as an adjunct to whole
brain radiation therapy (WBRT) for the treatment of patients with brain
metastases originating from breast cancer.  Although the FDA is not bound by
ODAC's recommendation, it generally takes such recommendations into
consideration when determining whether or not to approve a new drug product for
marketing in the United States.  The FDA's Division of Oncology Drug Products
is expected to take final action on the company's New Drug Application (NDA) by
June 4, 2004.

"We will await the FDA's final decision on our NDA and continue to believe
RSR13 in combination with whole brain radiation therapy is an effective
treatment for patients with brain metastases originating from breast cancer. We
hope the agency's final decision will acknowledge the clear unmet medical need
in this patient population," said Michael E. Hart, President and CEO of Allos
Therapeutics, Inc.  "Meanwhile, we continue to enroll patients in our
confirmatory Phase 3 trial, called ENRICH, initiated to evaluate the potential
of RSR13 as an adjunct to whole brain radiation therapy for the treatment of
women with brain metastases originating from breast cancer."

"Clinical trial results with RSR13 plus whole brain radiation therapy
demonstrate that patients with brain metastases from breast cancer can benefit
from this treatment by enhancing the effect of radiation," noted John H. Suh,
M.D., Clinical Director, Radiation Oncology, Brain Tumor Institute at the
Cleveland Clinic Foundation, Principle Investigator of the REACH Study (RT-009)
and Chairman of the ENRICH Study (RT-016).  "A new therapy that has a positive
effect on a patient's survival and quality of life would significantly improve
our ability to treat this patient population."

ODAC reviewed data submitted by the company to the FDA in a New Drug
Application (NDA 21-661), which the company believes demonstrates the safety
and efficacy of RSR13 as an adjunct to WBRT for the treatment of patients with
brain metastases originating from breast cancer.  The company's NDA included
data from a randomized, open-label 538-patient pivotal Phase 3 trial which
evaluated RSR13 as a radiation sensitizer for brain metastases.  While the
difference in overall survival between patients who received RSR13 plus WBRT
and patients who received only WBRT was not statistically significant, the
trial showed a positive survival benefit among patients with brain metastases
from breast cancer and confirmed RSR13's strong safety profile.  Patients with
brain metastases originating from breast cancer represent a subset of patients
that was not prospectively defined as an intent-to-treat subgroup in the Phase
3 trial.

In February 2004, the company launched a multi-center Phase 3 randomized open
label trial of RSR13 (efaproxiral) as an adjunct to WBRT for the treatment of
brain metastases originating from breast cancer.  The Phase 3 study, called
ENRICH (ENhancing Whole Brain Radiation Therapy In Patients with Breast Cancer
and Hypoxic Brain Metastases), is designed to compare the effect of WBRT with
supplemental oxygen with or without RSR13 in women with brain metastases
originating from breast cancer.  The study will also evaluate the safety
profile of RSR13 in this patient population.  The study will seek to enroll
approximately 360 patients at up to 50 cancer centers across North America. The
design of the study calls for two interim analyses for safety and efficacy. 
The company has successfully completed the FDA's Special Protocol Assessment
(SPA) for the ENRICH trial.  Under the SPA, the FDA evaluates whether the
protocol for a clinical trial is adequate to meet scientific and regulatory
requirements for marketing approval of the drug by the FDA.

"The National Breast Cancer Coalition (NBCC) looks forward to continuing to
work with Allos Therapeutics in support of the ongoing ENRICH trial," said Fran
Visco, President of NBCC.  "Our goal is to help find safe and effective
therapies that make a significant impact in the burden of breast cancer."

NBCC partnered with Allos to support the ENRICH trial design, oversight and
enrollment and to gain additional insight about how to improve radiation
treatment for women with brain metastases from breast cancer.  Through its
Clinical Trials Initiative, the NBCC is mobilizing its nation-wide network of
advocates to inform women about this trial.

Conference Call

Allos Therapeutics will hold a conference call at 5:15 p.m. EDT today to
discuss the outcome of the ODAC meeting on the company's investigational
radiation sensitizer, RSR13 (efaproxiral).  Investors and media are invited to
participate.

   Time:       5:15 p.m. EDT
   Date:       Monday, May 3, 2004
   Location:   The Hilton Hotel, Gaithersburg, MD
   Dial-in:    [phone] / [phone] international
   Webcast:    http://www.allos.com/ (homepage and investor relations section)



Interested parties unable to participate in the live conference call may access
a recorded rebroadcast by dialing 1-800- 428-6051, or [phone] for
international callers; the conference ID number is 353015.  The replay will be
available from 7:00 p.m. EDT on Monday, May 3, 2004 until 11:59 p.m. EDT on May
10, 2004.  In addition, the webcast will be archived for on-demand listening
for 30 days at http://www.allos.com/.

About RSR13 (efaproxiral)

RSR13 (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, RSR13 (efaproxiral)
has the potential to enhance the efficacy of standard radiation therapy. Unlike
chemotherapeutics or other radiation sensitizers, RSR13 (efaproxiral) 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, RSR13 (efaproxiral), 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, an injectable small molecule chemotherapeutic agent
that has a superior potency and toxicity profile relative to methotrexate and
other dihydrofolate reductase, or DHFR, inhibitors.  For more information,
please visit the company's web site at: http://www.allos.com/.

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 timing and outcome of the FDA's decision whether
or not to approve RSR13 for marketing in the United States, the company's
ability to successfully complete the ENRICH trial on schedule and in accordance
with regulatory requirements, and the company's ability to adequately
demonstrate the safety and efficacy of RSR13 for the treatment of brain
metastases from breast cancer or any other type of cancer, 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 for the year ended December
31, 2003, as amended.  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:  Monique M. Greer, VP, Corporate Communications and Investor

Relations of Allos Therapeutics, Inc., [phone], or Cell,

[phone], ; or Media, Fern Lazar of Lazar Partners

Limited, Cell, [phone], , or Amy Raskopf,

Cell, [phone], both for Allos Therapeutics, Inc.



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

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