Palatin Technologies Announces Phase 3 Data for LeuTech Infection Imaging Agent.

PRINCETON, N.J.--(BW HealthWire)--April 26, 1999--

"... confirm or rule out appendicitis both quickly and

accurately ..." -- No Blood Handling Needed

Palatin Technologies Inc (NASDAQ:PLTN) Monday reported the results of its recently completed Phase 3 clinical study of LeuTech(TM), the company's antibody-based infection imaging agent.

The trials were conducted at 10 sites, and involved 203 patients with equivocal (suspected) appendicitis, ranging in age from five to 86 years of age. According to the announcement by Palatin Chairman & Chief Executive Officer Edward J. Quilty, these data show that LeuTech is a highly accurate imaging agent that enables radiologists and nuclear medicine specialists to obtain images easily, in a very short period of time, with no blood handling. Complete data will be made public when articles are published in scientific journals. There are an estimated 250,000 cases of appendicitis in the United States each year, approximately 50 percent of which are equivocal.

LeuTech, which is a monoclonal antibody labeled with Technetium, is injected intravenously and accumulates quickly at the site of an infection, giving a bright, clear image on a gamma camera. According to the Phase 3 clinical results, the time from injection to the first positive image was as little as four minutes (38 percent of patients), and was typically eight minutes (the median of all patients). The data from the tests indicate that LeuTech detected appendicitis in 91 percent of positive subjects, and correctly predicted the absence of appendicitis in 96 percent of negative scans. Results are the same with and without SPECT computer aided image enhancement. No significant adverse events were reported during the study.

Frederick Weiland, M.D., FACNP, commented on clinical studies carried out at Sutter Roseville Medical Center in Sacramento, "LeuTech's performance in the diagnosis of suspected appendicitis in patients presenting with atypical signs and symptoms has turned our surgeons and our emergency room physicians into true believers. They found that LeuTech was the diagnostic procedure of choice and was preferred over all other traditional tests previously used to diagnose suspected appendicitis."

Weiland, Clinical Associate Professor of Radiology at the University of California at Davis, said that he has worked over the years with numerous monoclonal antibodies and peptide-based products, including other investigational infection imaging agents in recent clinical trials. "I am experienced with this type of radiopharmaceutical, and nothing I have used has been as promising as LeuTech," he said.

Eric Rypins, M.D., FACS, Chief of General Surgery at Tri-City Medical Center, Oceanside, Calif. commented, "At Tri-City Medical Center, we have been studying infection imaging agents for appendicitis for more than eight years, and I suspect that we have performed more screens than almost any other facility in the U.S. Our experience during the LeuTech clinical trials has convinced us that once FDA approved, it will almost certainly become the standard method at Tri-City for diagnosing appendicitis in patients with atypical symptoms. Moreover, it will likely find broader use in other hard-to-diagnose infections. There is not, in our experience, another product like it.

"LeuTech helped to either confirm or rule out appendicitis both quickly and accurately," Rypins added. "In addition, the changes in patient management in the LeuTech Phase 2 and Phase 3 trials improved both the quality and cost effectiveness of patient care in that we were able to avoid some unnecessary operations and admissions for observation."

Palatin Chief Operating Officer Charles L. Putnam said, "We were particularly pleased with the consistent performance of LeuTech over several trials of rigorous design. Unlike others studying this indication, we do not allow difficult cases to be set aside because the images are unclear or difficult to read. Our studies attempt to mirror the real world, where a decision is required on every case.

"We are meeting with the FDA next month to review the data," Putnam added, "and we expect to be able to submit our BLA (Biologics License Application) this summer. Assuming the process continues as planned and we receive FDA approval to market, we are hopeful that LeuTech will be available in the summer of 2000."

In February of this year, Palatin started a multi-site Phase 2 study of LeuTech for the detection of osteomyelitis, which is the second indication of several planned for LeuTech.

Palatin Technologies is a development-stage medical technology company involved in developing and commercializing products and technologies for diagnostic imaging, cancer therapy and ethical drug development based on its proprietary monoclonal antibody radiolabeling and enabling peptide platform technologies. For further information, visit the Palatin Web site at www.palatin.com.

For investor information, visit the Allen & Caron Inc Web site at www.allencaron.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. Since these statements involve risks and uncertainties and are subject to change at any time, the company's actual results could differ materially from expected results.