WASHINGTON -- A Food and Drug Administration advisoryboard on Tuesday unanimously recommended approval ofCentocor Inc.'s Myoscint for detection of the presence, locationand extent of myocardial necrosis in acute ischemic heartdisease. It was the first monoclonal antibody-based imagingagent to receive a recommendation for FDA approval.
Separately on Tuesday, Prudential Bache analyst JosephEdelman repeated a buy on Centocor, based largely on hisestimate that its Centoxin monoclonal antibody against gram-negative sepsis, once given final FDA approval, could have upto $1 billion in U.S. sales.
Edelman said that hospitals are budgeting about $1 billion forthe drug, based on an estimate that the 850 U.S. hospitals withmore than 400 beds are setting aside about $1 million each forthe drug, with smaller amounts being budgeted at smallerhospitals.
Stock of the Malvern, Pa., company closed unchanged Tuesdayat $48.75.
Myoscint (imciromab pentetate) is a cardiac imaging agent thatis radiolabeled with indium-111. It uses a monoclonal antibodyFab fragment bound to DTPA (diethylenetriaminepentaaceticacid) that seeks out and binds to myosin, a protein that isexposed in dead heart tissue. It can be used to diagnose heartattacks and assess the degree of heart damage.
Approval by the Biological Response Modifiers advisorycommittee "was really a very positive industry event for all thecompanies involved in the imaging field, and it appears thatthe FDA has gone well along the learning curve in terms of howto view these imaging agents," said PaineWebber analyst LindaMiller. Cytogen Corp. and Immunomedics Inc. are developingantibody-based cancer imaging diagnostics, she said.
Alex. Brown & Sons analyst David Webber estimated the U.S.market for Myoscint at $10 million. About 1.5 million nuclearimaging studies are used to assess cardiac function annually inthe United States, said Centocor spokesman Richard Koenig, andMyoscint may be used as an adjunct or in place of some ofthese.
Initial sales will not top $5 million because "there will be aslow introduction, given that it will change some of thetherapeutics in the cardiology and radiology field, and someinitial education will be needed," Miller told BioWorld. "Wehave an aggressive projection that ultimately it will be a $50million to 100 million product."
Miller and Webber agreed the approval will not have asubstantial impact on Centocor's stock price or earnings in1992.
Product labeling issues that remain to be worked out with theFDA include questions about how long Myoscint remainseffective after administration and its ability to detect heartattacks that may have occurred in previous months, Koenigsaid.
Centocor markets Myoscint in several European nations andwill market it in the United States through McNeilPharmaceutical, an affiliate of Johnson & Johnson.
-- Kris Herbst BioWorld Washington Bureau
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