Matrix Pharmaceutical Completes Enrollment in Trials of IntraDose Injectable Gel for Solid Tumors; Several data presentations scheduled for fall 1998.

FREMONT, Calif.--(BUSINESS WIRE)--Sept. 14, 1998--Matrix Pharmaceutical, Inc. (NNM: MATX) today announced that it has completed enrollment in both United States and European clinical trials of IntraDose(TM) (cisplatin/epinephrine) Injectable Gel for treatment of solid tumors and will present safety and efficacy data from these studies at several Fall 1998 medical meetings.

The IntraDose solid tumor trials are companion studies to Phase III registration-directed trials of IntraDose in patients with advanced head and neck cancer. Enrollment in the head and neck studies designed to support a submission of a New Drug Application at the U.S. Food and Drug Administration is projected to be completed next year.

The solid tumor studies have enrolled patients with a variety of tumor types, of which the most common types treated were chest wall tumors from recurrent breast cancer, esophageal tumors, and malignant melanoma.

A total of 127 patients have been enrolled in the IntraDose solid tumor studies. Full study results are expected to be available in the first half of 1999 after the most recently entered patients have completed follow-up. Interim data will be presented at the following Fall 1998 meetings:

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     --   Results from 30 recurrent breast cancer patients will be
          presented at the Federation of European Cancer Societies 1st
          European Breast Cancer Conference in Florence, Italy on
          September 30 and at the San Antonio (Texas) Breast Cancer
          Symposium, December 12.

     --   Data on a majority of the patients treated in these trials
          will be presented at the Chemotherapy Foundation Symposium
          XVI: Innovative Cancer Therapy For Tomorrow organized by the
          Mount Sinai Medical Center in New York on November 11-13.

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In addition, investigators will report at the meeting of the Radiological Society of North America, November 29 in Chicago, on the use of IntraDose in ongoing Phase II trials in liver cancer. Matrix's Radiopotentiator MPI 5020 will be the subject of presentations at the European Society for Therapeutic Radiology and Oncology, September 21 in Edinburgh, Scotland, and at the American Society for Therapeutic Radiology and Oncology October 25-29 in Phoenix.

"Completion of enrollment in the two IntraDose studies in solid tumors and the upcoming release of a substantial portion of the study data are significant accomplishments," said Richard D. Leavitt, M.D., Senior Vice President, Medical and Regulatory Affairs. "These studies expand the experience with IntraDose in various solid tumors in addition to head and neck cancer. We believe the study results will be important for physicians treating seriously ill patients with these cancers. We are also pleased with recent progress in enrolling patients in the pivotal head and neck cancer studies."

Located in Fremont, California, Matrix Pharmaceutical, Inc. uses patented drug delivery technologies to develop novel site-specific treatments for cancer. IntraDose Injectable Gel, the company's lead cancer product, is in Phase III studies for the treatment of head and neck cancer and other solid tumors. IntraDose is also being evaluated in Phase II studies in primary and metastatic liver cancer. MPI 5020, a locally injected gel designed to enhance the cytotoxic effects of radiation therapy, is in a Phase I/II trial in recurrent and metastatic breast cancer.

This press release contains, in addition to historical statements, certain forward looking statements relating to presentations of clinical trial results on IntraDose Injectable Gel, the projected completion of patient enrollment in IntraDose trials in head and neck cancer, and the clinical value of IntraDose. Such statements are based on management's current expectations and are subject to a number of factors and uncertainties set forth under the heading "Risk Factors" in the Company's Annual Report on Form 10-K for the year ended December 31, 1997 and Quarterly Report on Form 10-Q for the period ended June 30, 1998, which could cause actual results to differ materially from those described in the foward-looking statements.

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CONTACT: Matrix Pharmaceutical Inc.

Peter Dworkin, 510/494-7750