By Mary Welch

MedImmune Inc.'s Synagis, which the company describes as the first monoclonal antibody to be licensed for any infectious disease, was approved by the FDA Friday for the prevention of respiratory syncytial virus (RSV) in children and infants.

MedImmune, of Gaithersburg, Md., developed the drug and expects it to be available for the start of the RSV season this fall. With the approval, MedImmune receives a $15 million milestone payment from partner Abbott Laboratories, of Abbott Park, Ill.

"It's terrific news," said Wayne Hockmeyer, MedImmune's chairman and CEO. "We're obviously delighted with the approval and think the FDA did a terrific job with a very thorough but rapid review. We got approval six months after filing. We feel very good about helping these fragile children, thousands of whom die from RSV."

Formerly called MEDI-493, Synagis is a humanized monoclonal antibody that specifically targets RSV, which can result in fatal pneumonia in premature infants and other high-risk children. About 90,000 high-risk children, including those suffering from bronchopulmonary dysplasia, are hospitalized every year with severe forms of RSV. About 4,500 patients die each year.

New Drug Expected To Replace RespiGam

The standard RSV treatment is RespiGam, also from MedImmune, which is a polycolonal antibody enriched with neutralizing antibodies against RSV. It is administered by a four-hour intravenous infusion given monthly during the RSV season (generally September through April). Sales of RespiGam during last year's season were $70 million.

Synagis binds to the F protein on the surface of RSV, which is necessary for the virus to infect cells. All strains of RSV are then neutralized. Tests have shown Synagis is 50 to 100 times more potent than RespiGam, which was approved in January 1996.

"We expect Synagis to replace RespiGam," Hockmeyer said. "But we are not taking RespiGam off the market because there may be occasions where it might be preferred."

In addition to being more effective, another advantage of Synagis over RespiGam is administration. The former is given by intramuscular injection once a month in a doctor's office rather than infusion at a hospital. Synagis also is easier to make because it's engineered in the laboratory rather than formulated using donated blood. (See BioWorld Today Dec. 22, 1997, p. 1.)

Synagis is expected to cost about the same as RespiGam — $900 a dose — but ultimately will be cheaper because there will be no hospital expenses.

MedImmune formed an exclusive worldwide marketing alliance with Abbott to market Synagis and it will be co-promoted with the Ross Products Division of Abbott. Abbott's international division has the rights to market and distribute the drug outside the U.S.

The company filed its biologics license application with the FDA for Synagis in December 1997. In anticipation of Synagis' launch, MedImmune raised $66 million earlier this year. (See BioWorld Today. Jan. 14, 1998, p. 1.)

MedImmune, which posted year-end 1997 revenues of $80.2 million, was profitable the last two quarters. "We expect to end the year profitable," said Hockmeyer, "but we're not predicting how much."

MedImmune's stock (NASDAQ:MEDI) closed Friday at $56.75, unchanged. *