Nabi Biopharmaceuticals Announces Altastaph(TM) Phase II Trial Results in Neonates

ROCKVILLE, Md. -- Nabi Biopharmaceuticals today Phase II clinical trial results for Altastaph(TM) [Staphylococcus aureus Immune Globulin Intravenous (Human)]. This Phase II trial was conducted in premature, low birth-weight babies (neonates). Altastaph is the company's polyclonal antibody for prevention and treatment of Staphylococcus aureus infections, which can afflict at-risk patients including those who do not have time or are too immune-compromised to respond to a vaccine to prevent infection. Phase II clinical trials are generally small studies, sized to evaluate safety and the body's reaction to the drug under development. Results from this trial in neonates have demonstrated that Altastaph was safe and exhibited a good pharmacokinetic profile, the primary endpoints of the trial. The antibody levels following administration of Altastaph were well above the targeted level of 80-100 mcg/ml, which is believed to be protective against infections in neonates. However, the incidence rate of S. aureus infections observed in the neonates was very low, only three percent, versus an expected rate of five to seven percent based on published literature and recent clinical studies. As a result, the company is unable to make any inference about Altastaph's effect on infections in neonates, as only three infections were reported in each of the placebo and treated arms of the study.

Altastaph Development Program and Milestones

In order to maximize the clinical and commercial potential for Altastaph in preventing bacterial infections in neonates, Nabi Biopharmaceuticals plans to rapidly expand and advance its Altastaph development program. The company will focus its effort on its next generation Altastaph product that will be developed to prevent a majority (up to two-thirds) of bacterial infections observed in neonates (S. aureus Types five, eight and 336 and S. epidermidis). S. epidermidis, one of the most prevalent and dangerous bacteria to infect neonates, is a cause of significant illness and death.

Already during the fourth quarter of 2004, Nabi Biopharmaceuticals has completed formulation of a clinical lot of its S. epidermidis vaccine that can also be used as a stimulating agent for this next generation Altastaph product. The company expects to complete formulation of its Type 336 S. aureus vaccine in the first quarter of 2005 and will conduct initial safety and immunogenicity studies with these vaccines in 2005. This will allow for the manufacture of a clinical lot of the next generation of Altastaph in the second half of 2005 to support further clinical studies in 2006. The Altastaph development program, including the timing and type of clinical studies, will be determined after consultation with regulators in the United States and Europe. Altastaph has been granted fast track designation in the United States for its use in preventing infection in neonates.

"We are committed to the development of our novel antibody approach to prevent and treat deadly bacterial infections. We will continue to advance our work in neonates, recognizing the significant medical need in this very vulnerable patient population, while also defining other at-risk patient groups who could benefit from our approach," stated Thomas H. McLain, chairman, chief executive officer and president, Nabi Biopharmaceuticals. "The development program we have in place for this next generation product is important for many reasons. While our initial plan to begin Phase III clinical testing of Altastaph in 2005 will be delayed, we believe this next generation product will provide important advantages for physicians when compared to other similar products under development. By developing a product that can prevent both S. aureus and S. epidermidis infections, we will be in a unique position to help reduce illness, complications and death in at-risk patients. In addition, we plan to leverage the value of the patent portfolio we have built around our next generation programs."

Henrik S. Rasmussen, M.D., Ph.D., senior vice president, clinical research, medical and regulatory affairs and project management, Nabi Biopharmaceuticals, stated, "By including antibodies to prevent infections due to S. epidermidis or S. aureus Type 336, we should be able to demonstrate the benefits from Altastaph therapy against a broader range of infections that are the cause of this challenging and unmet medical need. This next generation product is expected to provide protection from all the strains of S. aureus bacteria causing serious infection in neonates. The additional protection against S. epidermidis bacteria will also be very important because these infections are a significant cause of illness and death in these patients."

About the Phase II Altastaph Study

The Altastaph study was a Phase II, double-blinded, placebo-controlled trial conducted in 20 neonatal intensive care units across the United States. Half of the 200 very low birth-weight infants studied received two doses of Altastaph 14 days apart starting three to seven days after birth and the other half were given placebo. The primary endpoints of the trial were to evaluate the safety and pharmacokinetics of Altastaph.

Source: Nabi Biopharmaceuticals