Access Pharmaceuticals Announces Publication of Thiarabine Combination Data

Combined with Clofarabine, Thiarabine Achieves High Cure Rate in a Colorectal Cancer Model

DALLAS, June 4 /PRNewswire-FirstCall/ -- ACCESS PHARMACEUTICALS, INC. , announced today that new Thiarabine preclinical efficacy data will shortly be published demonstrating that thiarabine combined with clofarabine provides much greater antitumor activity than achieved by either agent alone. In one colorectal cancer model, 66% of mice were cured of their tumors. The publication which will appear in the journal "Cancer Chemotherapy and Pharmacology," was based on work conducted by Access' collaborators at the Southern Research Institute. The paper is entitled "Enhancement of the in vivo antitumor activity of clofarabine by 1-beta-D-[4-thio-arabinofuranosyl]-cytosine" (thiarabine). A preprint of the paper is currently available for download from the journal's website.

"Thiarabine is a next generation nucleoside analogue, licensed by Access from Southern Research Institute," stated Jeffrey Davis, President & CEO. "Thiarabine has been in two Phase 1/2 solid tumor trials and was shown to have significant anti-tumor activity. Access is working with leukemia and lymphoma specialists at M.D. Anderson Cancer Center in Houston to initiate additional Phase 2 clinical trials in acute myeloid leukemia (AML), acute lymphocytic leukemia (ALL) and other indications. Additionally, we are actively seeking co-development partners, and believe that thiarabine could have applications in certain solid tumors as well," he continued.

In the study, thiarabine, clofarabine, and their combinations were tested in five tumor models. "In all cases, thiarabine demonstrated superior tumor growth inhibition than clofarabine when the agents were used alone," commented David P Nowotnik, Ph.D., Access Pharmaceuticals' Senior Vice President, Research and Development. "But, in the combination of these two agents, efficacy was dramatically superior to the use of either agent alone. Tumor regression and cures were observed in several models including colorectal cancer and leukemia. The combination of agents proved to be effective even when used at low doses, indicating a potential for effective treatment with a reduced side-effect profile."

Prior clinical studies have shown that the effectiveness of cytarabine, or Ara-C, (a close structural analog of thiarabine which is widely used in treating leukemia patients) can be improved by combining it with clofarabine in the treatment of leukemia patients. The Southern Research paper showed that thiarabine/clofarabine combinations have significantly superior efficacy to cytarabine/clofarabine combinations in the xenograft models. Thiarabine has previously been shown to have much better solid tumor efficacy than cytarabine in preclinical models.

About Access:

Access Pharmaceuticals, Inc. is an emerging biopharmaceutical company that develops and commercializes propriety products for the treatment and supportive care of cancer patients. Access' products include ProLindac(TM), currently in Phase 2 clinical testing of patients with ovarian cancer, and MuGard(TM) for the management of patients with mucositis. The company also has other advanced drug delivery technologies including Cobalamin(TM)-mediated targeted delivery and oral drug delivery, its proprietary nanopolymer delivery technology based on the natural vitamin B12 uptake mechanism; and Angiolix(R), a humanized monoclonal antibody which acts as an anti-angiogenesis factor and is targeted to breast cancer. Thiarabine is a new generation nucleoside analog which has demonstrated both pre-clinical and clinical activity in certain cancers. For additional information on Access Pharmaceuticals, please visit our website at www.accesspharma.com.

This press release contains certain statements that are forward-looking within the meaning of Section 27a of the Securities Act of 1933, as amended, and that involve risks and uncertainties. These statements include those relating to: clinical trial plans and timelines and clinical results for ProLindac and product candidates acquired in the MacroChem transaction, our ability to execute licensing agreements in the future, Access' plans to continue and initiate clinical trials, the value of its products in the market (including MuGard and the size of the overall market for mucositis products), its ability to achieve clinical and commercial success and its ability to successfully develop marketed products. These statements are subject to numerous risks, including but not limited Access' need to obtain additional financing in order to continue the clinical trial and operations and to the risks detailed in Access' Annual Reports on Form 10-K and other reports filed by Access with the Securities and Exchange Commission.

CONTACT: Stephen B. Thompson, Vice President, Chief Financial Officer,
Access Pharmaceuticals, Inc., +1-214-905-5100; Investor Relations, Donald
C. Weinberger or Diana Bittner (media), Wolfe Axelrod, Weinberger Assoc.
LLC, +1-212-370-4500

Web site: http://www.accesspharma.com/

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