Nabi Issue Patent on Staphylococcus aureus

Nabi has been issued a patent on a Staphylococcus aureus antigen, vaccines made from that antigen, and antibodies reactive to the antigen. The patent covers a polysaccharide antigen, 336PS, derived from a clinical isolate of S. aureus type 336 and also the antigen in combination with either or both type 5 and type 8 antigens.

"We believe that the discovery of S. aureus type 336 and the 336PS protective antigen represents a major breakthrough in the Nabi-StaphVAX program to develop products to protect against and treat staphylococcal infections," said Dr. Robert Naso, senior vice president at Nabi.

A staphylococcal vaccine, Nabi-StaphVAX, currently in phase III pivotal trials, is composed of type 5 and type 8 polysaccharides conjugated to carrier proteins. The vaccine is expected to address the majority of nosocomial S. aureus infections. Nabi is also testing a trivalent vaccine containing type 5, type 8 and type 336 antigens, a combination also claimed in the issued patent. An additional second generation product being developed is a pentavalent vaccine, to be named Nabi-StaphVAX +, containing types 5,8 and 336 antigens along with two specific antigens from S. epidermidis, another species of staphylococci associated with nosocomial infections. This vaccine is anticipated to prevent both S. aureus and S. epidermidis infections.

Two strains of S. aureus, known as type 5 and type 8 based on their capsular polysaccharide content, appear to cause approximately 85% of S. aureus infections in humans and approximately 50-60% of veterinary S. aureus infections. Epidemiology studies, however, show that the majority of the remaining S. aureus infections are caused by S. aureus type 336. The company has shown that an experimental vaccine containing 336PS can protect laboratory animals from lethal infection with type 336 S. aureus after bacterial challenge.

Nabi, a biopharmaceutical company, focuses on the development and commercialization of products that prevent and treat infectious and autoimmune diseases. Nabi also has three immunotherapeutic products already on the market: H-BIG, for the prevention of hepatitis B; WinRho SDF, for the treatment of immune thrombocytopenic purpura , an immune platelet disorder and suppression of Rh isoimmunization; and Autoplex T, for the treatment of hemophilia.

For more information: Tanina Frouge, Nabi. Tel: 561-989-5815.