MedImmune Inc. has outlined a plan to seek FDA approval for itsproduct, RespiGam, a polyclonal antibody being developed to preventand treat respiratory syncytial virus (RSV) disease in children.In December, the Blood Products Advisory Committee of the FDA'sCenter for Biologics Evaluation and Research voted 11-0 againstapproval of the drug, and 11-0 to require additional controlled studiesto determine safety and efficacy of RespiGam.Following the committee's unfavorable recommendation, MedImmune(NASDAQ:MEDI) stock fell 30 percent ($7 per share) to close at $16per share. The company's stock fell 25 cents Monday and 44 centsTuesday after the late Monday announcement, to close at $8.31 pershare.Some of the FDA committee's concerns centered around issues of themethodology used in the 249-patient, blinded, controlled trial inpremature infants, infants with bronchopulmonary dysplasia (BPD),and infants with congenital heart disease (CHD). Other concernsinvolved statistical analysis of the enrolled patient population, in lightof trial dropouts, and the fact that six deaths occurred among medicatedbabies vs. none among controls.The Gaithersburg, Md., company plans, assuming trial results arepositive, to file an amended product license application (PLA) forprevention of RSV disease based on results of the 249-patient study,called the Groothius trial; an open-label trial completed in April inwhich 68 premature infants or infants with BPD were treatedprophylactically with RespiGam; and an ongoing Phase III trial inchildren with CHD that is expected to enroll 320 patients, 250 of whomalready are enrolled and 70 who are expected to enter in the upcomingNovember-April RSV season.In addition, MedImmune intends to file a PLA amendment seekingmarketing approval of RespiGam to treat RSV disease, assumingsuccessful trial results. That submission will be based in part on twoPhase III trials completed in April. One involved about 100 high-riskinfants; the other about 100 infants who were not premature orsuffering from BPD or CHD."I think it's a very sound strategy," Eric Hecht, an analyst with MorganStanley & Co. of New York, told BioWorld. "These two productopportunities provide a base for being able to forecast future revenues.I think it's a viable product that has $75 million to $100 millionpotential revenues," annually in the U.S.Peter Drake, executive vice president of Vector Securities Internationalof Deerfield, Ill., told BioWorld, "I wouldn't call the strategyrevolutionary. I'd call it evolutionary. It's all part of the company'sapproach to securing another hearing with the FDA. I think it fits."David Mott, MedImmune's vice president, business development andplanning, told BioWorld that results of the two trials completed inApril should be available later this summer. The open-label trial alsowas completed in April. The cardiac trial, being held at 17 centers, isscheduled to continue into 1995. No other trials are planned to supporta PLA in the U.S.The company said more than 91,000 hospitalizations and 4,500 deathsoccur each year in the U.S. as a result of RSV infection in children,which is the leading cause of viral pneumonia and bronchiolitis ininfants. n

-- Jim Shrine

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