By Kim Coghill

Washington Editor

Nabi's stock dropped 14 percent Friday - after starting the day down about 30 percent - when the company said it likely will conduct an additional Phase III trial on StaphVAX for patients with end-stage renal disease (ESRD).

But the company said it also is likely to appeal the FDA's requirement for another study.

At least one analyst, however, listed the company's stock as a "good buy," stating that StaphVAX obviously works, and it was unfortunate the product missed its endpoint in a Phase III trial in 1,804 hemodialysis patients.

Back in September, Nabi, of Boca Raton, Fla., released preliminary data from the trial proving that StaphVAX was beneficial in patients up to 10 months, rather than the 12-month endpoint. Results of the double-blinded, placebo-controlled trial caused Nabi's stock to drop 40 percent that day, closing at $5.56, down $3.81. (See BioWorld Today, Sept. 20, 2000.)

Nabi's stock (NASDAQ:NABI) closed Friday at $4.687, down 78 cents.

"I think the product is working - it is just not working long enough," said Fariba Ghodsian, managing director of health care research at Roth Capital Partners Inc. in Los Angeles. "There's nothing magical about 12 months; that is just what the company said and the FDA adheres to the company's primary endpoint."

Ghodsian said StaphVAX is expected to produce about $300 million in annual revenue in hemodialysis patients.

David Gury, Nabi's chairman, president and CEO, would not go into details, but did say Nabi is seeking a potential partner for StaphVAX (Staphylococcus aureus Polysaccharide Conjugate Vaccine).

Nabi officials met with the FDA in December, at which time they were told another Phase III trial would be required.

The company's next step is to meet with the Vaccines and Related Biological Products Advisory Committee to discuss the second trial, Gury said. And although the company has not set in motion the new trial, "We are not going to wait until we get results from that discussion to develop our plans to move forward with an additional trial," Gury told BioWorld Today.

Gury acknowledged the Phase III trial missed the prospective 12-month endpoint, but said, "The trial shows that the ESRD patients have been able to maintain a significant reduction in blood-borne infections in this population for up to 10 months. Clearly, in this population we have shown that we have something that could protect them. Rather than denying the opportunity, we think that it is worth our having additional discussions with the vaccine panel to talk about that result."

There is no other product on the market to prevent infections in this population, Gury said. "This is a brand new concept and the Phase III trial we completed gives very good proof of principle of the whole concept of using antibodies to eliminate blood-borne infections."

Furthermore, the drug "very well could be an orphan drug," he said.

Gury said the FDA has not defined endpoints for the second trial, and the company has not defined "what the trial is, where it is going to be conducted or who is doing it."

Nabi and its contract manufacturer for StaphVAX, Dow Biopharmaceutical Contract Manufacturing Services, have made progress in developing commercial-scale manufacturing capacity for the product. Nabi expects to complete production of its first two commercial-process consistency lots in the second half of 2001 and the third consistency lot in early 2002.

Nabi also is finalizing plans to initiate a boosting study with StaphVAX in ESRD patients during the second quarter of 2001. The study will be conducted in patients who were enrolled in the first Phase III trial, and is expected to be complete by early 2002.

Meanwhile, during the second half of 2001, Nabi will initiate Phase I/II human clinical testing of Altastaph, a human polyclonal antibody preparation drug being developed to provide short-term protection from S. aureus infection in patients at immediate risk, such as trauma patients or premature newborns.