Coulter Pharmaceutical Reports Combined Clinical Trial Results with Bexxar in Various Stages of NHL; Company Also Reports Successful Re-Treatment with Bexxar.

PALO ALTO, Calif.--(BW HealthWire)--May 19, 1998--Coulter Pharmaceutical, Inc. (NASDAQ:CLTR) today presented overall clinical trial results from four separate investigational clinical trials of Bexxar (iodine I 131 tositumomab), the company's lead cancer therapy for the treatment of non-Hodgkins lymphoma (NHL).

The combined results from 116 patients with low-grade and transformed low-grade NHL revealed that 90 patients (78 percent) responded to Bexxar(TM) therapy, with 53 patients (46 percent) experiencing complete remission of their disease. In addition, 68 percent of patients who achieved complete remission continue in remission. As of May 1998, the longest duration of these remissions is at five years. Side effects were generally mild-to-moderate, transient flu-like syndrome and reversible low blood cell counts.

While data from each of the investigational trials have been reported separately, this meta- (combined) analysis demonstrates that Bexxar can produce durable complete remissions in all stages of low-grade and transformed low-grade NHL, from newly-diagnosed to end-stage disease. As one might expect, Bexxar appears to produce greater complete remission rates the earlier it is used in the progression of the disease, said Michael F. Bigham, president and chief executive officer of Coulter Pharmaceutical, Inc. These data will be included in our BLA submission planned for year end.

Data were generated from a total of 116 patients enrolled prior to August 1997 -- from newly-diagnosed patients who were previously untreated for their disease to advanced-stage patients who had failed chemotherapy more than four times prior to enrolling in a Bexxar investigational trial. The results included data from four investigational clinical trials of Bexxar, including a completed Phase I/II single-center trial, a completed Phase II multicenter trial, an ongoing Phase II trial in newly-diagnosed patients, and an ongoing Phase II trial comparing Bexxar to the B-1 unlabeled monoclonal antibody. In the newly-diagnosed patient population group, 100 percent of patients responded to treatment with a 71 percent complete remission rate.

The combined results were presented by Julie Vose, M.D., vice chairman of the Department of Internal Medicine at the University of Nebraska Cancer Center, at a poster session during this week's annual meeting of the American Society of Clinical Oncology in Los Angeles, CA.

In a separate published ASCO abstract, Coulter reported on successful re-treatment with Bexxar (iodine I 131 tositumomab) in patients who had relapsed from their initial Bexxar treatment. Data from 13 re-treated patients revealed that eight of 13 (62 percent) patients responded to re-treatment with four of 13 (31 percent) patients experiencing a complete remission with the second Bexxar treatment. In patients who achieved a complete remission to initial treatment, five of six (83 percent) experienced an overall response with three of six (50 percent) achieving a second complete remission. Bexxar was well-tolerated, with side effects consisting of mild-to-moderate, transient flu-like syndrome and reversible low blood cell counts. One patient tested positive for a seroconversion to antibody following treatment.

These re-treatment data demonstrate that patients can be safely re-treated with Bexxar following relapse of their prior treatment. In addition, for those patients who experienced a complete remission from initial Bexxar treatment, additional complete remissions appear to be achievable upon re-treatment, said Michael F. Bigham, president and chief executive officer of Coulter Pharmaceutical, Inc.

Bexxar, an antibody conjugated to iodine131, attaches to the CD20 antigen, found only on the surface of B-cells, including both non-Hodgkins lymphoma B-cells and some normal B-cells. Through this targeted approach, the tumor cells receive a greater concentration of the therapeutic radiation from Bexxar relative to normal tissues.

Non-Hodgkins lymphoma is a form of cancer that affects the blood and lymph tissues. NHL currently is the sixth leading cause of death among cancers in the United States and has the second fastest growing mortality rate. According to statistics from the National Cancer Institute, approximately 270,000 people are afflicted with NHL in the United States alone. Of the total, the company estimates that approximately 140,000 people have low-grade or transformed low-grade disease. There are approximately 54,000 new cases of NHL diagnosed each year.

Coulter Pharmaceutical, Inc. is engaged in the development of novel drugs and therapies for the treatment of people with cancer. The company currently is developing a family of cancer therapeutics based upon two drug development programs: therapeutic antibodies and targeted oncologics. The company's most advanced product candidate is Bexxar (iodine I 131 tositumomab), a monoclonal antibody conjugated to a radioisotope. Bexxar is currently being investigated in a pivotal Phase III investigational clinical trial for the treatment of non-Hodgkins lymphoma. Initial efforts in the targeted oncologics program are focused on the development of a tumor-activated peptide pro-drug version of doxorubicin to potentially treat certain solid tumor cancers.

Except for the historical information contained herein, the matters discussed in this news release are forward-looking statements that involve risks and uncertainties, including uncertainton proprietary technology, uncertainty of marke particular, see Risk Factors in the company's A CALIFORNIA

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Quarter Results

Business Editors

VANCOUVER, BRITISH COLUMBIA--(BUSINESS WIRE)--May 19, 1998--Ballard Power System (TSE:BLD.) (NASDAQ:BLDPF) Ballard Power Systems, Inc. today reported results for its first quarter ended March 31, 1998, and highlighted progress made in each of its business areas.

As Ballard continued its fuel cell development, cost reduction and development ofnto the testing phase. The net loss for the quarter was $8.2 million, or $0.35 per share, compared with $4.2s' equity of $303.3 million, including cash and short-term investments of $151.1 million.

In January,rd on June 5 - subject to regulatory and stockhel cells and Daimler-Benz and Ford now have minoding Ford's cash, technology, and assets worth mnt inuing a relationship that began in 1991.

Also during the quarter, the Chicago Transit Authority placed in regular transit service the three Ballard Fuel Cell bumal agreements related to the strategic investment of GEC ALSTHOM in Ballard Generation Systems (BGS), the Ballard subsidiary responsible for commercializing fuel cell stationary power plants. Separately, the Company announced a C$2.3 million order from Cinergy Technology, Inc. of Indianapolis, Indiana for the first customer field trial unit to be manufactured by BGS.

In February, Ballard received a C$2.5 million order from Honda R&D Co. Ltd. of Japan, a subsidiary of Honda Motor Company, to supply one-kilowatt Ballard Fuel Cell systems for demonstration, testing, and development of portable and specialty power applications.

Firoz Rasul, President and Chief Executive Officer, commented, "r near-term impact. The order from Cinergy mark milestones towards commercialization set out in our 1997 annual report."

Ballard Power Systems is theral Motors, Chrysler, Nissan, Hitachi, Honda, Mazda, Volkswagen, Volvo, GPU International and GEC ALSTHOM to develop zero-emission engines for vehicles and clean statio risks and uncertainties, including, without li product development, operations and marketing. Investors are encouraged to review the section Management Discussion and Analysis in Ballard's 1997 Annual Report titled "Operating Results, Capital Requirements, and Risks" (pages 22 to 26) for a more complete discussion of factors that could affect Ballard's future performance.

CONTACT: Ballard Power Systems Inc.

Paul Lancaster, 604/ 412-3195

604/ 412-4700 (FAX)

e-mail: [e-mail]

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