Hollis-Eden Pharmaceuticals Presents Positive Preclinical Data on Compounds Targeting Hormone Refractory Prostate Cancer.

SAN DIEGO -- Hollis-Eden Pharmaceuticals, Inc. (NASDAQ:HEPH) announced today that its scientists presented data detailing the activity of its steroid compounds in preclinical models of hormone refractory prostate cancer (HRPC). The results presented at the 12th International Congress on Hormonal Steroids, Hormones & Cancer being held September 13-16, 2006, in Athens, Greece, show that these compounds can inhibit adrenal steroid-induced generation and proliferation of prostate cancer tumors common in late-stage disease.

In a commonly used murine model for HRPC in humans, treatment with one of Hollis-Eden's compounds, HE3235, reduced tumor incidence in a dose dependent fashion and, in the high-dose group, completely prevented tumor growth (0/11), compared to 92% tumor incidence (11/12) in vehicle-treated animals. The Company presented preliminary data indicating that HE3235 inhibits the Src signal transduction pathway involved in androgen- and estrogen-driven HRPC. In its research, Hollis-Eden screened compounds from its library that inhibited adrenal androgen stimulated proliferation of human LnCaP prostate cancer cells in vitro. This system, designed to mimic HRPC in humans, was used to identify lead compounds that would then be tested in the murine model for HRPC.

The incidence of HRPC is estimated at approximately 90,000 in the U.S., resulting in an estimated 36,000 deaths each year. Hormone therapy that blocks production of testosterone can effectively control prostate disease for a period of time. However, hormone therapy will eventually fail and the prostate cancer will continue to grow and spread. HRPC is a disease state represented by tumors that develop the ability to grow despite low levels of testosterone. HRPC cells appear to be able to utilize other endogenously produced adrenal steroids as tumor growth factors.

"Hormone refractory prostate cancer represents a significant unmet medical need for patients with late-stage disease," stated Dwight R. Stickney, M.D., Vice President, Medical Affairs at Hollis-Eden. "The results presented today support the concept that it is possible to develop a targeted therapy to block HRPC-associated tumors by interrupting their ability to use adrenal steroids as growth factors. We are very encouraged with these results and are profiling HE3235 in additional studies. If these studies are successful, HE3235 could enter clinical trials in 2007."

"These results demonstrate the potential for a first-in-class drug therapy for hormone refractory prostate cancer patients," said Richard B. Hollis, Chairman and Chief Executive Officer of Hollis-Eden. "As we reported with these and other compounds at this conference, we are making considerable progress through our structure-activity relationship program in identifying new compounds from our Hormonal Signaling Technology Platform that may offer potential therapeutic benefit in a wide range of diseases and disorders."

Hollis-Eden Pharmaceuticals, Inc. is developing a proprietary new class of small molecule compounds that are metabolites or synthetic analogs of adrenal steroid hormones. These compounds, designed to restore the biological activity of cellular signaling pathways disrupted by disease and aging, have been demonstrated in humans to possess several properties with potential therapeutic benefit -- they regulate innate and adaptive immunity, reduce nonproductive inflammation and stimulate cell proliferation. The Company's lead product candidate, NEUMUNE(TM) (HE2100), is entering late-stage development for the treatment of Acute Radiation Syndrome (ARS), a life-threatening condition resulting from exposure to high levels of radiation following a nuclear or radiological incident, and is being explored for use in combating healthcare-associated infections. Hollis-Eden also is profiling optimized second-generation compounds for potential clinical development in a broad spectrum of therapeutic categories including hematology, metabolic disorders, autoimmune disorders, pulmonary diseases, oncology and infectious diseases. For more information on Hollis-Eden, contact the Company's website at www.holliseden.com.

This press release contains forward-looking statements concerning the potential and prospects of the Company's drug discovery program and its drug candidates. Any statement describing a goal, expectation, intention or belief of the Company is a forward-looking statement and should be considered an at-risk statement. Such statements are subject to certain risks and uncertainties, including the ability to complete preclinical and clinical trials successfully and within specified timelines, if at all; the ability to obtain regulatory approval for NEUMUNE under the U.S. Food and Drug Administration Animal Efficacy Rule, even if shown to be effective in preclinical studies; the ability to receive any stockpiling orders for NEUMUNE from the U.S. federal, state and foreign governments, even if approved by regulatory authorities; the Company's future capital needs; the Company's ability to obtain additional funding; the ability of the Company to protect its intellectual property rights and to not infringe the intellectual property rights of others; the development of competitive products by other companies; and other risks detailed from time to time in the Company's filings with the Securities and Exchange Commission. The actual results may differ materially from those contained in this press release.