Nabi Biopharmaceuticals Reports Encouraging Phase I/II Altastaph Results in Adults

ROCKVILLE, Md. -- Nabi Biopharmaceuticals today announced encouraging results from its U.S. Phase I/II clinical trial using Altastaph (Staphylococcus aureus Immune Globulin Intravenous (Human) to treat adult in-hospital patients with persistent

Staphylococcus aureus (S. aureus) bloodstream infections (bacteremia).  

In this study there was a 36 percent reduction in median time from administration of the

study drug to hospital discharge in the Altastaph-treated patients as compared

to the placebo-treated patients (nine days in the Altastaph group versus 14

days in the placebo group).  This substantial reduction in the length of

hospital stay for the Altastaph-treated group indicates that S. aureus

antibodies provided by Altastaph could be associated with considerable medical

benefit in the treatment of persistent S. aureus infections.

Altastaph is produced by immunizing healthy volunteers with StaphVAX

[Staphylococcus aureus Polysaccharide Conjugate Vaccine], Nabi

Biopharmaceuticals' vaccine in development for providing protection in at-risk

patients against S. aureus infections.  S. aureus bacteria are  the most

common cause of hospital-acquired infections and are becoming increasingly

resistant to antibiotics, which may result in illness and/or death.

The study was a double-blinded, placebo-controlled, randomized trial in 40

patients with persistent S. aureus blood stream infections (bacteremia)

designed to evaluate the safety of Altastaph and to measure S. aureus specific

antibody levels.  Patients were randomly allocated to receive two intravenous

doses of Altastaph or saline placebo in combination with standard-of-care

treatment, which included treatment with antibiotics.  The results of the

study demonstrated that Altastaph was well tolerated and no drug-related,

serious adverse events were reported.  Patients were able to maintain antibody

titers at or above levels previously demonstrated to be protective against S.

aureus infections in patients with end-stage renal disease (ESRD).  In

addition, as outlined above, Altastaph treatment was associated with a

substantial reduction in time to hospital discharge.

Thomas H. McLain, chairman, chief executive officer and president, Nabi

Biopharmaceuticals, stated, "We are very excited about seeing a meaningful

trend from a small safety and immunogenicity study that is supportive of the

benefit of Altastaph in the treatment of patients with a staph infection.  We

believe this is the first well-designed clinical study that has demonstrated a

therapeutic benefit from an antibody therapy in patients with serious

infection.  If we are able to duplicate these results in larger efficacy

studies, the high costs and serious complications associated with lengthy

hospital stays due to S. aureus bacterial infections could be significantly

reduced because patients treated effectively could go home sooner, greatly

reducing an increasing burden on the healthcare system."  McLain

continued, "Further, the demonstrated potential for using Altastaph

therapeutically in patients with existing serious infections substantially

increases the possible commercial opportunity for Nabi Biopharmaceuticals'

Gram-positive programs."

"These results also provide additional validation of Nabi's unique

approach of using antibodies to the polysaccharide capsule of S. aureus

bacteria to prevent and treat infection," said Raafat Fahim, PhD, senior

vice president research, technical and production operations. "StaphVAX and

Altastaph share a common mechanism of action.  When antibodies to S. aureus

attach to the outer capsule of the bacteria as it circulates in the blood, it

triggers an immune response, enabling the body's white blood cells to

recognize the bacteria and destroy it before it can contribute to more serious

infection."

Henrik Rasmussen, MD, PhD, senior vice president, clinical research,

medical and regulatory affairs, and project management, Nabi

Biopharmaceuticals, added, "Based on these results, we intend to advance our

current Altastaph formulation, which uses Type 5 and 8 antibodies, to further

assess its role in treating S. aureus infections.  We plan to meet with both

U.S. and European regulatory authorities to share the data from this trial and

work with them to define the next clinical steps for Altastaph.  Our

discussions will also consider recent clinical data from Brigham and Women's

Hospital (Clinical Infectious Diseases 2003; 36: 281-285), demonstrating that

patients treated for a serious staph infection and released from the hospital

are at a very high risk for a recurrence of another serious staph infection

within a relatively short period of time.  We believe a combination therapy

approach like this one will capture the therapeutic and preventive benefits of

our unique approach in patients afflicted with these life threatening

infections."

Altastaph is an investigational human antibody-based product containing

high levels of antibodies to capsular polysaccharides (protective outer sugar

coatings on S. aureus bacteria) from S. aureus Types 5 and 8, which together

account for approximately 85 percent of all S. aureus infections.  Altastaph is

produced by immunizing healthy volunteers with StaphVAX, Nabi

Biopharmaceuticals' vaccine in development for preventing S. aureus

infections.

Altastaph has been designated an orphan drug and has received Fast Track

Designation for providing immediate protection against S. aureus infections in

low birth-weight infants.  Altastaph is also being developed prophylactically

to provide short-term, immediate protection to patients who either cannot wait

for the vaccine effect to occur or whose immune system is too compromised to

mount an adequate response to a vaccine.

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

infection each year in the U.S. alone.  Within the country's 7,000 acute care

hospitals, S. aureus is the leading cause of hospital-acquired bloodstream

infections and is becoming increasingly resistant to antibiotics, rendering

them potent causes of illness and death with a crude mortality rate of

25 percent.  Patients at the greatest risk for these infections are those who

are immune-compromised, patients whose treatment requires invasive devices

such as prosthetic devices, catheters, artificial hips or knees, dialysis

access grafts, pacemakers, implantable defibrillators, or patients with

chronic illnesses, especially if they are being cared for in hospitals,

nursing homes, dialysis centers or similar institutions.

Furthermore, S. aureus bacteria are becoming increasingly resistant to

available antibiotics. Worldwide it is estimated that over 95 percent of

patients with S. aureus infections no longer respond to first-line

antibiotics, such as penicillin or ampicillin.  Methicillin is an alternative

treatment, but over 57 percent of strains of S. aureus are now Methicillin-

resistant (MRSA) in the United States.  The Centers for Disease Control

estimate that in 2002 there were approximately 100,000 cases of hospital-

acquired MRSA infections in the United States and the problem of these

infections is only worsening.  The rates of Methicillin-resistance are even

greater in certain Asian and European countries, (e.g., 72 percent MRSA rate in

Japan; 74 percent in Hong Kong).

Source: Nabi Pharmaceuticals