Washington Editor

Nabi Biopharmaceuticals said the FDA accepted for priority review the company's biologics license application for Nabi-HB Intravenous for the prevention of hepatitis B infection in transplanted livers.

Under priority review, the FDA is required to act on the application in six months, as opposed to the 10-month review period for standard applications. The agency also awarded Nabi-HB orphan status, a designation guaranteeing seven-year market exclusivity.

While Nabi-HB Immune Globulin currently is approved in the U.S. for preventing hepatitis B virus (HBV) upon acute exposure, Thomas Shrader, an equity analyst with Gerard Klauer Mattison & Co. in New York, told BioWorld Today that 80 percent to 90 percent of the product's annual sales can be attributed to off-label use for the chronic indication being sought.

"I would say there's not a lot more [U.S.] market to penetrate," Shrader said. "But approval as an orphan drug will leave other companies out. This is really starting to look like an attractive market at $40 million in the U.S."

He estimates U.S. sales in 2001 reached $30 million, and they should hit about $35 million for 2002. The greater market will be overseas, he said.

Both Shrader and David Gury, Nabi's chairman and CEO, said winning FDA approval is key to getting approval in international, untapped markets.

Nabi-HB, a sterile solution of human antibodies, would be administered intravenously on a periodic basis depending on the liver transplant patient's needs. Shrader estimates the treatments would cost about $50,000 each year.

"But a liver transplant cost 10 times that," he said. "It's a very expensive drug and only a few places can afford it. It's also very difficult to make, but that's what Nabi does best - it makes difficult-to-make antibodies."

Nabi, of Boca Raton, Fla., is studying another product, Civacir, for the prevention of hepatitis C in liver transplant recipients. Civacir, also an orphan product, is the subject of a Phase I/II trial. Gury said enrollment is completed and the company expects to have results later this year.

In other business, Nabi will initiate a confirmatory Phase III trial of StaphVAX (Staphylococcus aureus polysaccharide conjugate vaccine) for use in preventing blood-borne infections in end-stage renal disease (ESRD), once the company and its contract manufacturer, Dow Biopharmaceutical Contract Manufacturing Services, have product capacity satisfactory for the trial.

The company's stock fell 14 percent to close at $4.69 in February 2001 when company officials said the Phase III trial missed a prospective 12-month primary endpoint. However, the trial showed ESRD patients were able to maintain a significant reduction in blood-borne infections for up to 10 months. (See BioWorld Today, Feb. 5, 2001.)

In October, the company said preliminary results of a Phase I trial of NicVAX (nicotine conjugate vaccine) showed a single dose resulted in an immune response and generated nicotine-specific antibodies. Gury said Phase I/II trials in Europe and later in the U.S. are forthcoming.

Nabi's stock (NASDAQ:NABI) closed Thursday at $6.11, up 6 cents.