Palatin Technologies Reports Positive Results of a Clinical Study Evaluating the Co-administration of PT-141 and Viagra

CRANBURY, N.J.--(BUSINESS WIRE)--June 8, 2004--

Teleconference to be held 1:00 PM EDT on Wednesday, June 9, 2004

Palatin Technologies, Inc. (AMEX:PTN) announced today that it will be presenting an overview of the positive results from a clinical study evaluating the co-administration of PT-141 and Viagra(R) during a teleconference/webcast on Wednesday, June 9, 2004 at 1:00 PM EDT. PT-141 is Palatin's lead drug candidate under development for the treatment of male and female sexual dysfunction. Teleconference/webcast access information is provided at the end of this press release. Additionally, selected data slides from this clinical study will be available at the Palatin Technologies' corporate website (www.palatin.com) following the teleconference.

The purpose of the PT-141 and Viagra co-administration clinical study was to evaluate the potential synergistic effect of treating erectile dysfunction (ED) patients with both PT-141, which has a novel central nervous system (CNS) mechanism of action, and Viagra, a peripheral agent which is a PDE-5 inhibitor. The results of this study indicate that the co-administration of PT-141 and Viagra resulted in an increased degree of erectile activity relative to Viagra alone and that patients subjectively reported a better quality of erection relative to Viagra alone.

Dr. Carl Spana, president and chief executive officer of Palatin, stated, "These results are very encouraging and certainly justify the continued investigation of this treatment. The current IMS data (IMS is a leading provider of business information for the pharmaceutical industry) show that approximately 50% of the patients that receive an initial prescription for a PDE-5 inhibitor do not refill their prescription. Clearly, a significant percentage of these patients are not refilling their prescription due to lack of efficacy and/or intolerable side effects. The co-administration of a PDE-5 inhibitor and PT-141 may offer an opportunity to reclaim a significant portion of this patient population who, although motivated to seek treatment, remains untreated. We plan to file an Investigational New Drug (IND) application with the FDA and comprehensively evaluate multiple agent therapy with PT-141 and a PDE-5 inhibitor in additional clinical studies."

Study Design

-- The objective of this clinical study was to evaluate the efficacy and safety of co-administration of Viagra with PT-141 to 20 patients with ED.

-- RigiScan monitoring was employed over a 6-hour monitoring period to evaluate the duration and magnitude of each patient's erectile response. Two 30-minute episodes of visual sexual stimulation (VSS) were included in the 6 hour RigiScan monitoring period.

-- The study was designed as a double-blind, randomized, placebo-controlled, three-way crossover study evaluating the following three treatment arms:

-- 1. "Co-administration": 25 mg Viagra and 7.5 mg PT-141 intranasal spray;

-- 2. "Viagra-alone": 25 mg Viagra and placebo intranasal spray;

-- 3. " Placebo ": placebo tablet and placebo intranasal spray.

Study Results

-- Over the 6 hour RigiScan monitoring period, patients receiving the Co-administration treatment had, on average, increased erectile activity as compared to patients receiving either the Viagra-alone or Placebo treatment. The differences were statistically significant.

-- Patients were also asked to evaluate the quality of their erection on a visual analog scale (1-10 scale). Patients receiving the Co-administration treatment rated their best erection an average score of 8.2 compared to 6.8 for the Viagra-alone treatment and 5.7 for the Placebo treatment. This difference between Co-administration and Viagra-alone quality-of-erection scores was also statistically significant.

-- Importantly, there were no serious or significant adverse events in the study, including no significant differences in blood pressure, between any of the treatment arms. The only adverse event for patients receiving the Co-administration that was significantly different than either the Viagra-alone or Placebo treatment arms was flushing. Flushing occurred in 21% of patients receiving the Co-administration and 0% of the patients in the Viagra-alone and Placebo treatment arms.

"Multiple agent therapy with a PDE-5 inhibitor and PT-141 could constitute a treatment alternative for those patients for whom no single treatment is effective or well-tolerated. Treating an ED patient with lower doses of the two agents to achieve a clinically significant response with an optimal side effect profile is clearly an attractive treatment option that warrants further evaluation," stated Dr. Harin Padma-Nathan, a clinical professor of urology at the Keck School of Medicine at the University of Southern California, Los Angeles and director of the Male Clinic in Beverly Hills. Dr. Padma-Nathan's research and clinical practice are focused on pharmacotherapy for sexual dysfunction.

On June 9, 2004 at 1 PM EDT, Dr. Carl Spana, president and chief executive officer of Palatin Technologies, will moderate the teleconference/webcast and present the clinical trial results. The presentation will be followed by commentary by Dr. Harin Padma-Nathan, who will discuss the relevance of these clinical trial results to the members of the medical community who treat ED patients.

              Teleconference & Webcast Access Information

--  Conference Call Live              June 9, 2004 at 1:00 p.m. EDT 
    Domestic Dial-In Number           1-800-915-4836 
    International Dial-In Number      1-973-317-5319

--  Conference Call Replay            June 9-16, 2004, 11:59 a.m. EDT 
    Domestic Dial-In Number           1-800-428-6051 
    International Dial-In Number      1-973-709-2089 
    Enter Pass Code I.D. # 360019

--  Webcast Live and Replay Access    www.palatin.com 

About Erectile Dysfunction (ED)

ED is defined as the consistent inability to attain and maintain an erection sufficient for sexual intercourse. The condition is correlated with increasing age, cardiovascular disease, hypertension, diabetes, hyperlipidemia and smoking. In addition, certain prescription drugs and psychogenic issues may contribute to ED. It is estimated that some degree of ED affects one half of all men over the age of 40 and that 150 million men worldwide suffer from ED.

About PT-141

PT-141 is the first of a new drug class called melanocortin agonists being developed to treat sexual dysfunction. The mechanism of action of PT-141 may offer significant safety and efficacy benefits over currently available products because it acts on the pathway that controls sexual function without acting directly on the vascular system. Clinical data indicates that PT-141 may be effective in treating a broad range of patients suffering from ED. The nasal formulation of PT-141 being developed is as convenient as oral treatments, is more patient-friendly than invasive treatments for ED, such as injections and trans-urethral pellets, and appears to result in a rapid onset of action.

About Palatin Technologies, Inc.

Palatin Technologies, Inc. (AMEX: PTN) is a development-stage biopharmaceutical company focused on discovering and developing melanocortin (MC)-based therapeutics. The company is currently conducting clinical investigations with its lead drug PT-141, an MC receptor agonist, for the treatment of male and female sexual dysfunction. Palatin is also developing a product for infection imaging, NeutroSpec(TM), based on a proprietary radiolabeled monoclonal antibody. Palatin's patented drug discovery platform, MIDAS(TM), streamlines the drug design process with an efficient approach to identify lead compounds from protein targets for drugs. For further information, visit the Palatin web site at www.palatin.com.

Statements about the Company's future expectations, including development and regulatory plans, and all other statements in this document other than historical facts, are "forward-looking statements" within the meaning of Section 27A of the Securities Act of 1933, Section 21E of the Securities Exchange Act of 1934 and as that term is defined in the Private Securities Litigation Reform Act of 1995. The Company intends that such forward-looking statements be subject to the safe harbors created thereby. Palatin's actual results may differ materially from its historical results of operations and those discussed in the forward-looking statements for various reasons, including, but not limited to the Company's ability to carry out its business plan, successful development and commercial acceptance of its products, ability to fund development of technology, the risk that products may not result from development activities, protection of its intellectual property, ability to establish and successfully complete clinical trials for product approval, need for regulatory approvals, dependence on its partners for development of certain projects, and other factors discussed in the Company's periodic filings with the Securities and Exchange Commission. The Company is not responsible for events not updated after the date on this press release.