ROCKVILLE, Md. _ MedImmune Inc.'s Respigam, animmunoglobulin designed to reduce the severity ofrespiratory syncytial virus (RSV) in infants, on Fridaywon a recommendation for approval from the FDA'sBlood Products Advisory Committee.
The decision marks a hard-earned comeback both for theimmunoglobulin and the Gaithersburg, Md., firm, whichtwo years ago saw its initial application rejected by thecommittee on grounds that MedImmune's research wasimproperly designed and statistically flawed.
This time MedImmune's research _ which found thatRespigam safely reduced both the severity of disease andthe need for hospital care _ won praise from severalcommittee members, who termed the results"convincing."
"We're pleased. It's been a long haul," David Mott,MedImmune's president and CEO told BioWorld Today.He said the company hopes to win FDA approval in timeto launch Respigam into the marketplace by the fall of1996.
"This is a seasonal disease," Mott said. "What we _ andthe FDA _ would like to do is get this to children assoon as possible."
Spread by direct contact with infectious secretions, RSVis a leading cause of pneumonia and other lowerrespiratory ailments in infants and children. It has beenlinked to as many as 91,000 hospitalizations and 4,500deaths nationwide each year. Although adults alsobecome infected, most suffer only common colds.
The advisory panel recommended that the FDA approvethe drug to prevent "serious lower respiratory tractinfection in children younger than two years of age withbronchopulmonary dysplasia or a history of prematurity."
The vote was eight to three, with no abstentions.
George Siber, director of the Massachusetts Public HealthBiologic Laboratories, of Boston, said that Respigam isfiltered from donated blood plasma, which is then treatedwith a solvent, a detergent and other means to eliminatethe risk of infection with HIV, hepatitis B and othermicrobial agents.
But useful plasma is hard to find, Siber said. From 3,000to 6,000 donors must be screened to identify 300 whohave antibodies capable of neutralizing the respiratoryvirus.
Mott said plasma drawn from those donors yields enoughRespigam to treat about 400 patients _ each one ofwhich would need 10 vials containing 2.5 grams ofimmunoglobulin to make it through the season.
MedImmune's latest research, called the "Prevent" trial,involved 510 infants _ most of them premature _ at 54medical centers around the U.S. The average gestationalage was 28.5 weeks, and 60 percent of the infants hadbronchopulmonary dysplasia, Edward Connor,MedImmune's vice president for clinical research, toldthe advisory committee.
Most of the 250 infants in the treatment group receivedfour or five intravenous infusions of Respigam during thecold and flu season. The rest of the children, who wererandomly assigned to a control group, received a placebocontaining albumen.
Overall, the study found that 20 of the 250 patients takingRespigam had to be hospitalized for RSV pneumonia,compared with 35 of the 260 who received placebo, for a40.6 percent reduction in the number of hospitalizationsamong those treated with the drug. Those who were givenRespigam also spent less time in the hospital than thosewho were given placebo, Connor said.
Neal Halsey, director of the division of disease control atJohn's Hopkins University in Baltimore, told the advisorycommittee, "The data seem to indicate to me that theproduct is effective for the population as a whole."
He added that the statistical analysis also turned up noevidence of different levels of efficacy in subgroups ofchildren, when the group was broken down by age orother factors.
Naomi Lubin, of Children's Hospital National MedicalCenter in Washington, said the study's results "were farmore convincing than what we saw two years ago."
Panel members, however, debated one statistical findingthat seemed to suggest Respigam was less effective forchildren younger than six months of age.
But statistical experts from MedImmune and FDA, whoendorsed the quality of the research after analyzing100,000 pages of data, said that the study was notdesigned to elicit data on subgroups of patients. They saidthat the evidence, taken as a whole, suggested Respigameffectively prevents RSV disease in all age groups ofchildren.
To resolve the dispute _ and clear up any remainingquestions _ MedImmune has agreed to undertake aPhase IV study of the drug upon receiving FDA approval.
Committee member June Osborne, professor ofepidemiology, pediatrics and communicable diseases atthe University of Michigan School of Public Health, inAnn Arbor, said the committee's work was only a firststep in the process of introducing Respigam into clinicaluse around the country.
"The phase IV trial will serve to fill in some of theblanks," she said.
Mott said MedImmune had not yet completed work on itsstrategy for sales and distribution of Respigam.
Gordon Bray, director of clinical development for BaxterHealthcare Corp., of Deerfield, Ill., which in June risked$9.5 million on rights to market Respigam outside NorthAmerica, said Friday the gamble appears to have been awise one.
"Obviously, we're pleased by the committee's decision,"he said. n
-- Steve Sternberg Special To BioWorld Today
(c) 1997 American Health Consultants. All rights reserved.