National Editor

Using lessons learned from the first Phase III trial of StaphVAX, Nabi Biopharmaceuticals Inc. started the second Phase III study - intended to be pivotal - with the vaccine designed to block Staphylococcus aureus in end-stage renal disease patients.

"We should have results mid-2005 and be able to file our biologics license application by the end of 2005," said Mark Soufleris, vice president of investor and public relations for Rockville, Md.-based Nabi.

About 3,000 patients on hemodialysis will be enrolled at about 200 sites in the U.S., using the peak efficacy point of the first trial - eight months - as the primary endpoint, with added patients for statistical power.

In September 2000, Nabi offered preliminary data from the first trial in 1,804 hemodialysis patients showing StaphVAX, a polysaccharide conjugate vaccine, was beneficial up to 10 months but not statistically significant at the 12-month endpoint. (See BioWorld Today, Sept. 20, 2000.)

The company's stock fell 40 percent, or $3.81, on that unfavorable news, closing at $5.56. Results were published last year in The New England Journal of Medicine.

The company's stock (NASDAQ:NABI) rose 39 cents Monday to close at $8.61.

"The FDA basically said, Look, pick an endpoint that's going to work,'" Soufleris said.

Patients in the new trial will be randomized to get an intramuscular injection of StaphVAX or placebo upon entry. All subjects will be followed for at least 12 months, with the primary endpoint being incidence of bloodstream infection (bacteremia) caused by types 5 and 8 S. aureus through eight months after vaccination.

"We'll give everyone a booster dose at eight months," Soufleris said, because hemodialysis patients are at chronic risk for infections.

Secondary endpoints in the trial include the incidence of S. aureus bacteremia at six, 10, 12, and 14 months, as well as the cost of infections that occur during the study period.

Each year, more than 2 million patients in the U.S. get a hospital-acquired infection, according to the U.S. Centers for Disease Control and Prevention in Atlanta. S. aureus is the most common single cause, with a death rate of 11 percent to 43 percent because of serious complications and resistance to most antibiotics.

The patient population StaphVAX aims for is projected to continue to grow because of more patients with complications from diabetes, which often leads to loss of kidney function.

Thomas Shrader, analyst with Harris Nesbitt Gerard in New York, projected peak sales of StaphVAX in the end-stage renal disease (ESRD) setting at $150 million to $250 million. There's no other vaccine available, Soufleris noted.

"Today, it's traditional antibiotics to treat patients when they've got infections," he said.

In July, Nabi raised $32.9 million in a private placement to advance StaphVAX and to help buy PhosLo (calcium acetate), another product for ESRD patients, from Braintree Laboratories Inc., of Braintree, Mass., for a total of $90 million in cash plus 1.5 million shares of stock. PhosLo, sold in tablet and gel-cap form since 1991, targets hyperphosphatemia, or elevated levels of phosphate in the blood. (See BioWorld Today, June 25, 2003, and July 15, 2003.)

PhosLo and StaphVAX "tie together very nicely," Soufleris said.

Nabi also has a $35 million credit facility with Wells Fargo Foothill Inc., a subsidiary of San Francisco-based Wells Fargo Bank, to help with the PhosLo purchase.

To StaphVAX and PhosLo for ESRD patients, Nabi might eventually add Altastaph, a vaccine the company believes could work for anyone at risk of infection who doesn't respond to StaphVAX because of a compromised immune system.

"It's created by donors being vaccinated by StaphVAX," Soufleris told BioWorld Today. "We harvest the antibodies they produce and essentially sell those, so you have immediately available antibodies." Altastaph is in a Phase II study in low-birth-weight infants.

Nabi sells PhosLo and four other pharmaceuticals, as well as diagnostics and antibody plasma products, and the company is operating from revenues derived from those, Soufleris said.

At the end of the second quarter, Nabi had "just short of $59 million cash," he said. Then came the July financing, and the company "wrote a check for $60 million" in connection with the PhosLo buy, Soufleris said.

"We have not been burning since 2000," he said. "The cash that remains on our balance sheet is more or less an insurance policy."

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