ROCKVILLE, Md. -- A Food and Drug Administration advisorycommittee on Thursday voted unanimously to recommendapproval of Miles Laboratories' recombinant Factor VIII bloodclotting agent for hemophilia A patients.
The nine-member Blood Products Advisory Committeerecommended use of the Miles product, licensed fromGenentech Inc., both in patients previously treated with bloodproducts and for those who have not been treated forhemophilia.
The committee also recommended approval of an rFVIIIproduct developed by the Hyland Division of Baxter HealthcareCorp. under license from Genetics Institute Inc., but only forpreviously treated hemophilia A patients.
The majority voted against recommending approval of Baxter'srFVIII for previously untreated patients (PUPs). Members saidthey did not receive sufficient data from Baxter to recommendthat approval.
Genentech stock (NYSE:GNE) closed unchanged Thursday at $31;Genetics Institute (NASDAQ:GENI) was up 25 cents at $39.13.
rFVIII is the largest and most complex protein ever cloned andreproduced by genetic recombination for human use, and it is"the ultimate answer to providing viral safety to all hemophiliaA patients," said Dr. Craig M. Kessler, associate medical directorof the National Hemophilia Foundation.
Kessler noted that viral inactivation and elimination procedureshave largely eradicated the threat of contamination byhepatitis and HIV viruses of the highly purified plasma-derived FVIII products now used as a clotting agent forhemophiliacs. But, he said, there are concerns about shortagesof plasma-derived products and the appearance of viruses thatcannot be inactivated or eliminated.
The committee did not find that Baxter's rFVIII was any lesssafe or effective than the Miles product, said Paul Haas, a non-voting member who represents consumers and a professor ofeconomics at Bowling Green State University in Ohio. "We areuncomfortable with the data that we have (from Baxter) onlybecause there isn't enough there to look at," Haas said.
Baxter presented data on 42 patients after 15 months ofclinical trials, while Miles' study of 72 PUPs began in January1989.
Earlier studies have shown that patients treated with FVIIIdevelop immunoglobins that act as inhibitors to the agent.Clinical data presented by both companies indicated that PUPsare more likely to develop inhibitors than patients previouslytreated with blood products.
The committee acknowledged that inhibitors were "low leveland transient" in rFVIII, while plasma-derived productgenerates high levels. Members voted to recommend continuedstudies of inhibitors in PUPs.
The number of PUPs is relatively small and consists largely ofthe 400 to 500 hemophilic newborns each year in the UnitedStates, said a Miles spokesman. There are 20,000 previouslytreated hemophiliacs, of which about 12,000 require activetreatment, he said.
Miles has received orphan drug status for its product. However,the two companies previously agreed that if either won orphanstatus, the other company would be allowed to market itsrFVIII, Carl Brooks, president of Baxter's Hyland Division, toldBioWorld.
In 1989, GI and Baxter announced a worldwide patent cross-licensing agreement with Genentech and Miles.
-- Kris Herbst BioWorld Washington Bureau
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