June 2, 2003

News Release: OvaRex(R) Study Demonstrates Clinical Benefit for Ovarian Cancer Patients

AltaRex Corp. (TSX: AXO, OTC: ALXFF) ('AltaRex'or the 'Company') announced today that Jonathan Berek, MD, Chief of the Division of Gynecologic Oncology UCLA's Jonsson Cancer Center in Los Angeles, presented results of a phase II trial of OvaRex(R) (oregovamab) at the 39th annual meeting of the American Society of Clinical Oncologists (ASCO) in Chicago. The results of this placebo-controlled trial in stage III/IV ovarian cancer patients identified a population that exhibited a strongly favorable outcome. In this group of patients, median time to disease relapse for OvaRex(R) treated patients (n=34) was 24 months, versus 10.8 months for placebo (n=33) treated patients (p=0.06). The study was a randomized Phase II multi-center trial assessing the ability of OvaRex(R) to influence time to progression for advanced ovarian cancer patients with no evidence of disease and normalized CA125 following front-line surgery and chemotherapy. Currently there is no approved therapy for patients in this treatment period. The study population was typical of this cancer population, and the treatment arms were well balanced. One hundred forty-five (145) patients were randomized into the study. The clinical outcome favored OvaRex(R) treatment, 13.3 versus 10.3 months in placebo treatment (p=ns), for the primary outcome of time to relapse, as measured by the investigator or independent endpoint monitoring committee. Further analysis of the data revealed a well-defined population that demonstrated a dramatic clinical benefit as compared to placebo. This group is characterized by patients with optimal surgical cyto-reduction, a favorable CA125 response to chemotherapy, and no evidence of disease following chemotherapy. Patients with less favorable outcome and response to surgery and chemotherapy did not appear to benefit from the treatment following front- line chemotherapy. The side effect profile for OvaRex(R) treatment was similar to placebo, unlike most cancer therapeutics, which can have significant toxicity.

'These results, if confirmed in the currently enrolling phase III trials, will address a significant unmet medical need with the promise of an important new therapeutic approach for women with advanced ovarian cancer,'said Dr. Jonathan Berek, the Principal Investigator of the study.

Unither Pharmaceuticals, a wholly-owned subsidiary of United Therapeutics Corporation and our strategic partner and licensee for OvaRex(R), recently announced the initiation of two identical pivotal Phase III clinical trials, called IMPACT I and II, being conducted at centers throughout the United States. OvaRex(R) MAb is an investigational immunotherapeutic monoclonal antibody being developed for the treatment of stage III/IV advanced ovarian cancer following successful completion of front-line therapy. A list of participating sites in the IMPACT I and II trials may be obtained by accessing www.clinicaltrials.gov and entering the keyword: OvaRex.

Ovarian cancer, the deadliest of women's reproductive cancers, is the fifth leading cause of cancer deaths among U.S. women, occurring in 1 out of 57 women. The American Cancer Society estimates that this year, in the United States, there will be 25,400 new cases of ovarian cancer diagnosed, and 14,300 American women will die from this disease. Overall, the five-year survival rate for stage III/IV disease is estimated to be 31%. Although most patients initially respond to surgery and chemotherapy completely, the relapse rate is estimated to be approximately 85%. Once relapse occurs, there is no known curative therapy.

In April 2002, United Therapeutics signed an exclusive license with AltaRex Corp. for OvaRex(R) and four other monoclonal antibody immunotherapies (antibodies that activate a patient's immune response to treat cancer) that were being developed for treatment of ovarian, prostate, lung, breast, multiple myeloma and other forms of cancer. 'This strategic partnership with United Therapeutics represents an important milestone for AltaRex in bringing its lead Product OvaRex(R) to the marketplace,'said Dr. Noujaim, President and CEO of the Company.

AltaRex Corp. is focused on the research, development and commercialization of foreign antibodies that modulate the immune system for the treatment of certain cancers and other diseases where there exists an unmet medical need. Additional information about AltaRex Corp. can be found on its website at www.altarex.com.

This news release contains forward-looking statements that involve risks and uncertainties, which may cause actual results to differ materially from the statements made. For this purpose, any statements that are contained herein that are not statements of historical fact may be deemed to be forward- looking statements. Without limiting the foregoing, the words 'believes,' 'anticipates,''plans,''intends,''expects'and similar expressions are intended to identify forward-looking statements. Such risks and uncertainties include, but are not limited to the Company's need for capital; the risk that the Company can not raise funds on a timely basis on satisfactory terms or at all; the need to obtain and maintain corporate alliances, such as the alliance with United Therapeutics Corporation, and the risk that the Company cannot establish corporate alliances on a timely basis, on satisfactory terms, or at all; changing market conditions; uncertainties regarding the timely and successful completion of clinical trials and patient enrollment rates, uncertainty of pre-clinical, retrospective, early and interim clinical trial results, which may not be indicative of results that will be obtained in ongoing or future clinical trials; whether the Company and/or its collaborators will file for regulatory approval on a timely basis; uncertainties as to when, if at all, the FDA and other similar regulatory agencies will accept or approve regulatory filings for the Company's products; the need to establish and scale-up manufacturing processes, uncertainty as to the timely development and market acceptance of the Company's products; the risk that the claims allowed under any issued patent owned or licensed by the Company will not be sufficiently broad to protect the Company's technology, that any patents issued to the Company will not be sustained if challenged in court proceedings or otherwise or that third parties will be able to develop products or processes that do not infringe valid patents owned or licensed by the Company, and other risks detailed from time-to-time in the Company's filings with the United States Securities and Exchange Commission and Canadian securities authorities. The Company does not assume any obligation to update any forward-looking statement.

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Contact: Rob Salmon Chief Financial Officer (780) 989-6708 This email address is being protected from spambots. You need JavaScript enabled to view it.

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For further information: Rob Salmon, Chief Financial Officer for AltaRex Corp., +1-780-989-6708, rsalmon(at)altarex.com

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

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