Updated Survival Data from Phase I/II Trials of NeoRx's STR for Multiple Myeloma Presented at ASH Annual Meeting.

SEATTLE -- Six-year Survival Now Demonstrated in Two Patients Treated at Phase III Dose

NeoRx Corporation (NASDAQ:NERX) today announced updated survival data from multiple myeloma patients previously treated in Phase I/II trials of STR(TM), the Company's investigational bone-targeted radiotherapy. The data were presented at the 46th annual meeting of the American Society of Hematology (ASH) in San Diego.

The Phase I/II trials involved multiple myeloma patients at different clinical stages who received various doses of STR and melphalan prior to transplantation. Among the 10 patients treated with STR at a dosage equivalent to that in the current pivotal Phase III trial (750 mCi/m2), the four-year survival rate was found to be 70 percent and the complete response rate is 40 percent. Two of three patients who received STR treatment at the 750 mCi/m2 dose six years ago remain alive. Patients will continue to be followed for safety and survival. The estimated median survival, using the Kaplan-Meier method, for all 83 patients treated with STR in two Phase I/II studies was found to be 5.4 years. These results compare favorably with data from the International Blood and Marrow Transplant Registry, which reports a three-year survival rate of 53 percent for myeloma patients receiving standard transplant regimens. Other published data indicate a median survival of 4.6 years for patients treated with traditional chemotherapy and transplant.

"The survival benefit and disease response reported in the STR trials are very encouraging in the multiple myeloma treatment setting and provide continued evidence supporting the use of STR in combination with stem cell transplant therapy for patients with multiple myeloma," said Mark Goodman, M.D., University of Miami Hospital, who presented the data at ASH. "Additionally, the disease response rate and safety profile from the Phase I/II trials for patients who received STR treatment at the dosage used in the ongoing Phase III trial support this as an effective dosage. We expect to see further updates as patients continue to be monitored for safety and survival."

NeoRx is developing STR for use with high-dose chemotherapy and autologous (self-donor) stem cell transplantation to treat multiple myeloma and other cancers that arise in or spread to the bone and bone marrow.

The Company is currently conducting a multi-center, randomized, controlled Phase III pivotal trial designed to evaluate the safety and efficacy of STR in patients with primary refractory multiple myeloma. Patients eligible for this study will have failed to achieve at least a partial response to conventional therapy and have been undergoing treatment for less than 18 months. The trial is expected to enroll approximately 240 evaluable patients, where half of the patients would be treated with STR. The study's primary endpoint is to determine the rate of complete response using well-validated criteria at six months post-transplant.

In addition, NeoRx has a submitted a protocol with the U.S. Food and Drug Administration (FDA) for a Phase II clinical study of STR in patients with advanced breast cancer that has metastasized to the bone.

About STR

STR is an investigational, targeted cancer therapeutic that delivers radiation directly to cancer in the bone and bone marrow, sparing other tissues from radiation's effects. STR is an injectable drug that may be administered on an out-patient basis. It is composed of a bone-targeting molecule, DOTMP, in a stable complex with the radioisotope, holmium-166. When injected into a patient's bloodstream, STR rapidly binds to bone mineral to treat the bone and bone marrow with a brief, intense dose of radiation to destroy cancer cells in the bone and marrow. STR that does not bind to bone is rapidly eliminated shortly after administration. STR treatment is followed by high-dose chemotherapy and autologous stem cell transplantation, the standard of care for myeloma patients. Autologous transplantation uses the patient's own peripheral blood stem cells, collected prior to treatment, to restore bone marrow function.

About Multiple Myeloma

Multiple myeloma (also referred to as myeloma, or plasma cell myeloma) is a cancer of the plasma cells, the antibody-producing white blood cells formed in the bone marrow. In patients with multiple myeloma, malignant plasma cells are produced in abundance in the bone marrow, replacing normal plasma cells and other white blood cells important in immune function. The malignant plasma cells produce a characteristic paraprotein (also called myeloma protein, or M protein) that can be detected in the blood or urine. Myeloma cells may form tumors throughout the skeleton and the widespread bone lesions may cause pain and fractures. Multiple myeloma is the second most common blood cancer, currently affecting an estimated 40,000 people in the United States. The American Cancer Society estimates that 15,270 new cases will be diagnosed and 11,070 patients will die from the disease. Overall, fewer than half of all patients survive more than three years after diagnosis.

About NeoRx Corporation

NeoRx is a cancer therapeutics development company. The Company's product pipeline includes STR, currently in a pivotal Phase III clinical trial for patients with primary refractory multiple myeloma, and NX 473, a next-generation platinum therapy that the Company plans to evaluate in the treatment of patients with advanced lung and colorectal cancers. For more information, visit www.neorx.com.

This release contains forward-looking statements relating to the development of the Company's products and strategic goals that are subject to certain risks and uncertainties, which could cause actual results to differ materially from those projected. The words "believe," "expect," "intend," "anticipate," "plan," variations of such words, and similar expressions identify forward-looking statements, but their absence does not mean that the statement is not forward-looking. These statements are not guarantees of future performance and are subject to certain risks, uncertainties and assumptions that are difficult to predict. Factors that could affect the Company's actual results include the availability of working capital and financing sources for the development of NeoRx's product candidates, the progress and costs of clinical trials and the timing of regulatory approvals, the availability of clinical materials from third-party suppliers, NeoRx's ability to manufacture STR in a timely and cost-effective manner, NeoRx's ability to successfully commercialize product candidates, and other risks and uncertainties described in NeoRx's current and periodic reports filed with the Securities and Exchange Commission, including NeoRx's Annual Report on Form 10-K for the year ended December 31, 2003, and Quarterly Report on Form 10- Q for the quarter ended September 30, 2004. Readers are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date of this release. The Company undertakes no obligation to update any forward-looking statement to reflect new information, events or circumstances after the date of this release or to reflect the occurrence of unanticipated events.

NeoRx and STR are trademarks or registered trademarks of NeoRx Corporation in the United States and/or foreign countries.

(C) 2004 NeoRx Corporation. All Rights Reserved.