December 7, 1998
Source: Aronex Pharmaceuticals, Inc

Aronex Pharmaceuticals Starts Clinical Trial of Atragen^® for Prostate Cancer

The Woodlands, Texas, December 7, 1998 -- Aronex Pharmaceuticals, Inc. (Nasdaq National Market: ARNX), announced today that the Company has submitted a New Drug Application (NDA) to the U.S. Food and Drug Administration (FDA) for ATRAGEN^® for the treatment of patients with acute promyelocytic leukemia (APL), for whom therapy with tretinoin is necessary but for whom an intravenous administration is required.

Geoffrey F. Cox, Ph.D., Chairman and CEO of Aronex Pharmaceuticals, said, "We are very pleased to announce the Company's first NDA submission. This event marks a major milestone in the development of the Company. It is a testimony to the very capable clinical and regulatory team at Aronex Pharmaceuticals and to the enormous efforts of the many employees involved in the program."

In addition to APL, ATRAGEN is being evaluated in a staged program of pilot studies in a variety of hematologic malignancies and solid tumors. Investigators from The University of Texas M.D. Anderson Cancer Center will present today encouraging preliminary data from a Phase II clinical trial in APL at the American Society of Hematology 40th Annual Meeting in Miami, Florida.

Aronex Pharmaceuticals, Inc. is a biopharmaceutical company that develops and commercializes proprietary innovative medicines to treat cancer and infectious diseases. Aronex Pharmaceuticals currently has four products in clinical development, two of which are in an advanced stage, as well as a pipeline of additional products.

Any statements which are not historical facts, including statements regarding the Company's clinical development programs and the expected timing of clinical trials and NDA filings, contained in this release are forward looking statements that involve risks and uncertainties, including but not limited to those relating to product demand, pricing, market acceptance, the effect of economic conditions, intellectual property rights and litigation, clinical trials, governmental regulation, competitive products, risks in product and technology development, the results of financing efforts, the ability to complete transactions and other risks identified in the Company's Securities and Exchange Commission filings.

SOURCE Aronex Pharmaceuticals, Inc.

CONTACT: Connie Stout, Associate Director, Corporate Communications, Aronex Pharmaceuticals, Inc., 281-367-1666; or Michelle Linn, Vice President, Feinstein Kean Partners Inc., 617-577-8110, for Aronex Pharmaceuticals, Inc. Web site: www.aronex-pharm.com/ (ARNX)