By Randall Osborne

As MedImmune Inc. gears up for the anticipated launch of its monoclonal antibody for respiratory syncytial virus (RSV), another "launch" has made inroads against the infection that strikes about 4 million children in the U.S.

Scientists aboard the space shuttle Columbia grew RSV antibody crystals last summer, and the knowledge they gained of the antibody's three-dimensional atomic structure may speed development of a vaccine against the virus, said Steve Roy, spokesman for the National Aeronautics and Space Administration (NASA).

"A more uniform crystal turns into a better X-ray," said Roy. The improved X-ray allows for a more precise study of the antibody's interaction with the virus.

"It's a fairly new science, and very promising," Roy said.

The space experiments, sponsored by NASA's Microgravity Research Program, have been ongoing for about 10 years to determine the three-dimensional structures of proteins, Roy said. Away from gravity's influence, researchers are able to grow larger, higher-quality crystals, which then are analyzed through X-ray diffraction. (See BioWorld Today, Aug. 30, 1994, p. 1.)

The antibody was developed and produced by Intracel Corp., of Issaquah, Wash., which develops diagnostic products. Late last year, the firm completed a Phase III clinical trial of OncoVax, a colon cancer vaccine that is manufactured using the patient's own cancer cells.

Gaithersburg, Md.-based MedImmune's drug Synagis is an injected monoclonal antibody that targets RSV. The company submitted a biologics license application for Synagis to the FDA late last year. Anticipating a possible approval this fall, the company raised $66 million in a private placement. (See BioWorld Today, Jan. 14, 1998, p. 1.)

MedImmune's already-marketed product against RSV is Respigam, an immune globulin drug administered by infusion over a period of hours.

RSV can be fatal for premature infants and those who suffer from bronchopulmonary dysplasia. In the U.S., about 4,500 of those patients die every year.

A vaccine for RSV, formulated with help of the NASA-sponsored findings, would be a threat to neither of MedImmune's drugs, said Julie Adamou, spokeswoman in investor relations for the company.

"In the population of kids that Synagis and Respigam targets — the high-risk and premature infants — a vaccine wouldn't work," Adamou said. "Their immune systems aren't mature enough to develop a response."

American Home Products, of Madison, N.J., has been developing an RSV vaccine in collaboration with MedImmune "for years," she added.

"They're in Phase II trials right now," she said. Under an agreement revised more than three years ago, MedImmune is entitled to royalties on sales of the vaccine. (See BioWorld Today, Oct. 30, 1995, p. 1.)

A vaccine would supplement MedImmune's drugs, Adamou said.

"Kids will continue to get the disease throughout life," she said. "It's just that when they're infants, they can't handle it." *