Coulter Pharmaceutical Begins Outpatient Treatment with Bexxar.

PALO ALTO, Calif.--(BW Healthwire)--Sept. 4, 1997--Coulter Pharmaceutical Inc. (NASDAQ:CLTR) today announced that Bexxar(TM) (its radiolabeled monoclonal antibody), under development for the treatment of non-Hodgkin's lymphoma, is being administered on an outpatient basis under newly-enacted Nuclear Regulatory Commission (NRC) Guidelines.

The guidelines, which went into effect on May 29, 1997, allow for the treatment and release of patients who receive Bexxar, replacing a previous requirement for hospitalization following certain radiotherapies.

"Having Bexxar administered on an outpatient basis provides a significant commercialization advantage as it eliminates the expense of hospitalization as well as fulfills the patient's desire to go home following therapy," said Michael F. Bigham, president and chief executive officer of Coulter Pharmaceutical. "The therapy is already being administered in a simple, two-step dosing regimen. It now offers the convenience of an outpatient treatment setting."

University of Michigan Comprehensive Cancer Center reported that it had begun treating patients with Bexxar on an outpatient basis. "Our first patient was sent home immediately following Bexxar therapy," said Richard L. Wahl, M.D., professor of internal medicine and radiology at the University of Michigan. "From our experience, Bexxar is easy to administer and well-tolerated by patients. Allowing patients to go home following this therapy is a significant added convenience."

Coulter Pharmaceutical also announced that the Bexxar manufacturing process has been successfully transferred to a central production facility. Previously, Coulter's unlabeled monoclonal antibody was shipped to clinical trial sites where the last step of radiolabeling was conducted.

Nordion of Ontario, Canada, Coulter's contract manufacturing partner, is currently radiolabeling the product at its facility and then shipping Bexxar in "ready-to-administer" form to clinical trial sites across the United States. The new central production process was implemented to facilitate broad patient access to the therapy by providing for convenient administration.

Bigham added, "The treatment of patients on an outpatient basis and the availability of centrally-radiolabeled antibody are significant commercial milestones. We are very pleased with our pre-commercialization progress and expect these recent accomplishments to provide patients greater access to the therapy while streamlining costs for the provider."

Bexxar, which is an antibody radiolabeled with iodine- 131(I131), attaches to a protein found only on the surface of B-cells, both non-Hodgkin's 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. The therapy is administered in a regimen consisting of two intravenous doses given about one week apart -- first an imaging dose and then a therapeutic dose.

Coulter is evaluating Bexxar in a multicenter, pivotal Phase II/III clinical study in low-grade non-Hodgkin's patients who are refractory to chemotherapy. The company plans to complete enrollment in this trial as early as December 1997 and expects to file a biologics license application (BLA) with the FDA in the second half of 1998.

Coulter Pharmaceutical 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 platform technologies: conjugated antibodies and tumor-activated peptide (TAP) pro-drugs.

The company's most advanced product candidate is Bexxar (previously referred to as the B-1 Therapy) for the treatment of non-Hodgkin's lymphoma. The company also is developing a TAP 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 uncertainties related to product development, uncertainties related to the need for regulatory and other government approvals, dependence on proprietary technology, uncertainty of market acceptance of Bexxar or the company's other product candidates and other risks detailed from time to time in the company's filings with the Securities and Exchange Commission. In particular, see "Item 1. Financial Business-Risk Factors" of the company's Form 10-K for the year ended December 31, 1996.

CONTACT: Coulter Pharmaceutical

Sylvia Wheeler, 415/842-7306