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,
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