Studies Evaluate Safety and Efficacy of Bayer's

Kogenate Product Line / Studies Presented at the XVII Congress ofthe International Society of Thrombosis and Hemostasis Washington (PROTEXT) - Results were announced today from twoclinical trials presented at the International Society ofThrombosis and Hemostasis annual meeting, evaluating the safetyand efficacy of Bayer's Kogenate product line. The first studyshowed Kogenate, Bayer's first generation recombinant factor VIIItreatment, did not increase the incidence of factor VIIIantibodies in this study's patient population with severeHemophilia A. The second trial showed that patients treated withthe second generation of Kogenate (Recombinant Factor VIIIFormulated With Sucrose) achieved hemostasis (blood clotting) inall episodes of bleeding or surgery. Kogenate and the Incidence of FVIII Inhibitors This study, presented by Alan R. Giles, of Queen's Universityand Kingston General Hospital, is a three-year follow-upsurveillance study designed to assess the occurrence of sideeffects, including the incidence of factor VIII inhibitors, in562 previously treated patients whose therapy was converted fromplasma derived factor VIII (pdF.VIII) to recombinant factor VIII(rF.VIII). The results of this study showed that over threeyears, only 4.5% of patients (n=446) developed inhibitors toFVIII. Additionally, of the 25 patients who tested positive forfactor VIII inhibitors prior to study initiation, 84%subsequently tested negative for FVIII inhibitors afterconversion to Kogenate. Study investigators concluded thatrecombinant factor VIII products did not increase the incidenceof inhibitors in these patients who were previously treated withplasma derived factor VIII. According to the National Hemophilia Foundation, 6-21% ofpatients with Hemophilia A develop antibodies to factor VIII(inhibitors) after they have received factor VIII treatment ofany kind. These inhibitors can prevent patients from respondingto treatment with infused factor VIII protein and, in some cases,worsen a patient's bleeding pattern. Most inhibitors to FVIII inpatients with Hemophilia can be suppressed, however, somepatients will respond poorly to treatment with factor VIIIprotein during the period of time required for antibodysuppression, thus leaving them more vulnerable to bleedingepisodes induced by trivial injuries. "Historically, there has been a concern over the possibilitythat using recombinant factor VIII products may be associatedwith an increase in the incidence of FVIII inhibitors. This studyis exciting because it shows that Kogenate did not increase theoccurrence of inhibitors in this population of previouslytransfused hemophiliacs and suggests that these concerns appearto be unfounded," said Alan R. Giles, lead investigator of thestudy. A Second Generation of Kogenate Results from a multicenter, international clinical trial werealso presented at the conference by Dr. Hans-Hermann Brackmann ofthe Institute for Experimental Hematology and TransfusionMedicine at the University of Bonn. This study evaluated thesafety and efficacy of Recombinant Factor VIII Formulated WithSucrose in 72 patients (34 in Europe, 38 in North America) withHemophilia A. This study showed that hemostasis (bloodcoagulation) was achieved in all cases of bleeding episodes andsurgery. Overall, of 2585 bleeding episodes during the study,79.9% (2066) were effectively treated with one infusion ofRecombinant FVIII Formulated With Sucrose, while 93.3% (2413)were effectively treated with 1-2 infusions. Additionally, 22minor and major surgical procedures were successfully performedin 15 patients with no occurrence of bleeding complications, andno patients required treatment with another type of factor VIIIconcentrate. In 12,548 infusions with Recombinant FVIII Formulated WithSucrose, adverse events were reported in only 2% (249) with 0.2%(24) of these reported as possibly being drug-related. Studyinvestigators concluded that all adverse events in this studywere mild to moderate except one where the patient sufferedintermittent chest pain with palpitations ending after treatmentwith analgesics. "As a Company committed to the advancement of hemophiliatreatment, Bayer's goal is to offer patients a product with theefficacy of Kogenate coupled with improvements afforded by theremoval of human plasma proteins in its purification andformulation," said Peter Larson, M.D., Kogenate Clinical ProjectDirector from Bayer. Kogenate and the second generation of Kogenate Formulated WithSucrose are genetically engineered versions of the naturallyoccurring coagulation protein that is missing or deficient inHemophilia A patients. Kogenate was approved by the U.S. Food andDrug Administration in 1993. Since its introduction, over 2billion units of Kogenate have been infused. A licensingapplication for the second generation of Kogenate, formulatedwith sucrose, is currently under review by the FDA. Hemophilia A is an inherited blood clotting disorder affectingmore 50,000 individuals worldwide and characterized by prolongedblood clotting time. Patients with Hemophilia A have deficient ordefective coagulation factor VIII, a naturally occurring proteininvolved in coagulation, the process that normally controlsbleeding by changing blood from a liquid to a solid state. Duringthe clotting process, factor VIII is required for the productionof fibrin, which in turn creates a "plug" at the injury site. Thefibrin "plug" helps to seal the wound and stop the flow of blood.The majority of patients with Hemophilia A must be treatedregularly by intravenous infusion of factor VIII to stop orprevent bleeding. Bayer Corporation is a research-based company with majorbusinesses in health care and life sciences, chemicals andimaging technologies. The company had 1997 sales of $9.3 billionand employs more than 26,000 people. Bayer Corporation isinvesting $9 billion in capital expenditures and research anddevelopment from 1995 through the year 2000. 1998 capitalinvestment and R&D expenditures are projected to total $1.7billion. Bayer Corporation, with headquarters in Pittsburgh, PA.,is a member of the worldwide Bayer Group, a $32 billion chemicaland pharmaceutical company based in Leverkusen, Germany. otsOriginal Text Service: Bayer Corporation Internet:http://www.newsaktuell.de Contact: Nancy Wright of BayerCorporation, (USA) 203-812-6436; or Miriam Weber or Lisa Fern,Media, (USA) 212-213-0006, or Mike Sinclaire, European Media,+44-171-665-6643, all of Burns McClellan, for Bayer Corporation

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