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Study Indicates A.P. Pharma Polymer System Could Advance Clinical Utility of DNA Vaccines Against Cancer and Viral Infections; Data Published in Nature Materials

REDWOOD CITY, Calif.--(BUSINESS WIRE)--Feb. 24, 2004--A.P. Pharma, Inc. (Nasdaq:APPA), a specialty pharmaceutical company, today announced that results of a study conducted at the Massachusetts Institute of Technology (MIT) indicate that a proprietary A.P. Pharma polymer delivery system could advance the clinical utility of DNA vaccines as well as other nucleic acid-based therapeutics against viral infections and cancers. Study results were reported in the paper, "Molecularly engineered poly (ortho ester) microspheres for enhanced delivery of DNA vaccines," published online in the February 2004 issue of Nature Materials.

The study, directed and sponsored by A.P. Pharma's principal scientist Jorge Heller, in collaboration with an MIT team under the direction of professor Robert S. Langer and post doctoral fellow Chun Wang, investigated the use of synthetic biodegradable polymers, poly (ortho ester) (POE) microspheres, specifically designed for enhancing the immunogenicity of DNA vaccines. The POE microspheres allowed DNA release in synchrony with the body's immune system, thus increasing the potency of the response. A vaccine based on a model antigen elicited both an antibody response and a cellular immune response in mice when formulated in a specific type of POE microsphere, resulting in suppression of the growth of tumor cells displaying the model antigen.

"There is much interest in developing DNA vaccines to defend against viral infections, such as HIV, as well as various forms of cancer," said Dr. Heller. "They have potential as an alternative to conventional vaccines, which are based either on proteins or on killed or weakened pathogens that can potentially infect the recipient. Some other approaches to formulate DNA vaccines have been reported to cause degradation of the DNA. While admittedly early stage, our study results indicate that the molecularly engineered POE microspheres we studied successfully released intact DNA to the appropriate immune system cells without degradation and elicited a potent immune response." He added, "This has been a major problem with some other polymer systems that have shown DNA degradation prior to delivery to the cell."

An abstract of the manuscript is available on the Nature Materials' Web site at http://dx.doi.org/10.1038/nmat1075.

The full article may be purchased online or accessed through a subscription to Nature Materials.

About A.P. Pharma

A.P. Pharma is a specialty pharmaceutical company focused on the development of ethical (prescription) pharmaceuticals utilizing its proprietary polymer-based drug delivery systems. The Company's primary focus is the development and commercialization of its bioerodible injectable and implantable systems under the trade name Biochronomer. Initial target areas of application for the Company's drug delivery technology include pain management, anti-nausea, inflammation, oncology and ophthalmology applications. The Company's product development programs are funded by royalties from topical products currently marketed by pharmaceutical partners, by proceeds from the divestitures of its cosmeceutical and analytical standards product lines and by fees it receives from collaborative partners. For further information visit the Company's Web site at www.appharma.com.

Forward-looking Statements

Except for historical information, this news release contains certain forward-looking statements that involve risks and uncertainties including, among others, uncertainty associated with timely development, approval, launch and acceptance of new products, establishment of new corporate alliances and progress in research and development programs. Other risks and uncertainties associated with the Company's business and prospects are identified in the Company's filings with the Securities and Exchange Commission. The Company does not undertake to revise these forward-looking statements to reflect events or circumstances occurring in the future.

CONTACT:
A.P. Pharma, Inc.
Gordon Sangster, 650-366-2626
or
Investor Relations Contacts:
Lippert/Heilshorn & Associates
Jody Cain / Bruce Voss, 310-691-7100
jcain@lhai.com / bvoss@lhai.com

SOURCE: A.P. Pharma, Inc.