Nabi Biopharmaceuticals Announces Initiation of New StaphVAX(R) Immunogenicity Study in Orthopedic Surgery Patients

ROCKVILLE, Md.  -- Nabi Biopharmaceuticals has announced the initiation of its U.S. StaphVAX [Staphylococcus aureus Polysaccharide Conjugate Vaccine] immunogenicity study in orthopedic surgery patients with implanted devices.  The study is a double-

blinded, placebo-controlled trial that will evaluate a total of 120 patients

undergoing orthopedic surgery that involves the implantation of synthetic

material (such as hip or knee replacement).  Results from this study are

expected to be available by the end of the third quarter of 2005.

The objective of this study is to evaluate safety and antibody levels in

these patients over a six-month period.  The company expects this study will

demonstrate that after vaccination with StaphVAX, this large at-risk patient

group can achieve antibody levels equal to or greater than the levels proven

to be protective in immune-compromised end-stage renal disease (ESRD)

patients.  Patients undergoing orthopedic surgery are at high risk of

developing S. aureus bacteremia and subsequent infections because of the

invasive nature of this surgery.

"Staph aureus infections and their growing resistance to traditional

antibiotics are serious public health issues, particularly for those patients

undergoing orthopedic surgeries," said Henrik Rasmussen, MD, PhD, senior vice

president of clinical research, medical and regulatory affairs and project

management, Nabi Biopharmaceuticals.  "By effectively immunizing patients at-

risk against Staph aureus infections, StaphVAX could represent a completely

new paradigm in addressing this growing, unmet medical problem.  Each year

more than 2.6 million people undergo orthopedic implant surgery in the United

States and an additional 800,000 hip and knee replacement surgeries are

performed in Europe.  These patients are all at an increased risk of being

afflicted with a staph infection as a complication of this surgery."

The company also announced that patient enrollment in a similarly designed

immunogenicity study in cardiovascular surgery patients with implanted devices

is accelerating, and results are now expected to be available by the end of

the third quarter of 2005.  This will be in sufficient time to support the

filing of the StaphVAX Biologics License Application (BLA) in the United

States before the end of 2005.

An estimated 12 million patients are at risk for developing a S. aureus

infection each year in the United States.  Within the country's 7,000 acute

care hospitals, S. aureus is one of the three leading causes of hospital-based

bloodstream infections and has a crude mortality rate of 25 percent.  Patients

at greatest risk are those who are immune compromised, those whose treatment

requires an invasive surgical procedure, such as implanted prosthetic devices,

and those with chronic illnesses such as ESRD patients on dialysis.

S. aureus bacteria are the most common cause of hospital-acquired

infections and are becoming increasingly resistant to antibiotics, rendering

these bacteria a potent cause of illness and death.  The incidence of S.

aureus infections, and in particular strains that are resistant to

Methicillin, MRSA, is continuing to increase rapidly.

Worldwide, it is estimated that more than 95 percent of patients with S.

aureus infections no longer respond to first-line antibiotics, such as

penicillin or ampicillin.  In response, Methicillin became the standard of

care for treating these infections.  Recent data have shown dramatic increases

in Methicillin-resistant S. aureus (MRSA) in most European countries,

including an increase from 30 percent to 44 percent in the U.K. and an

increase from 22 percent to 28 percent in Belgium.  Recent data published in

Clinical Infectious Diseases that was based on a comprehensive survey of 49

major hospitals in the United States found the rate of MRSA more than doubled

over a seven-year period, from 22 percent in 1995 to 57 percent in 2002.  The

situation is even more dire in certain Asian countries, with rates of MRSA in

Japan; Hong Kong and Taiwan reaching 72 percent, 74 percent and 61 percent,

respectively.

StaphVAX (Staphylococcus aureus Polysaccharide Conjugate Vaccine) is an

investigational vaccine designed to prevent S. aureus infections in at-risk

patients. This novel application of Nabi Biopharmaceuticals' vaccine

technology stimulates the patient's immune system to build antibodies to the

most common forms of S. aureus infections without the development of

resistance.  In December 2004, Nabi Biopharmaceuticals submitted a

Marketing Authorization Application (MAA) to the European Agency for

Evaluation of Medicinal Products (EMEA) under the Centralized Procedure for

approval to market StaphVAX within the European Union.  StaphVAX is currently

in a confirmatory Phase III clinical trial in the United States.  This double-

blinded, placebo-controlled and randomized trial is being conducted in ESRD

patients undergoing hemodialysis.  The nearly 4,000-patient study is designed

to demonstrate statistical significance with a clinical reduction of 50

percent or more in types 5 and 8 S. aureus infections.  The company plans to

file a Biologics License Application incorporating results from this Phase III

trial and immunogenicity studies in other at-risk patient populations before

the end of 2005.

Source: Nabi Biopharmaceuticals