Prescription Drugs

CLINICAL PHARMACOLOGY AHF is the specific clotting factor deficient in patients with hemophilia A (classical hemophilia). Hemophilia A is a genetic bleeding disorder characterized by hemorrhages which may occur spontaneously or after minor trauma. The administration of Bioclate (antihemophilic factor) † provides an increase in plasma levels of AHF and can temporarily correct the coagulation defect in these patients. Pharmacokinetic studies on sixty-six (66) patients revealed the circulating mean half-life for rAHF to be 14.4 ±4.9 hours, which was not statistically significantly different from plasma-derived Antihemophilic Factor (Human), HemofilÒM, (pdAHF), which had a mean half-life of 14.0 ±3.9 hours (n = 59). Mean highest in vivo recovery in plasma was also similar at 2.18 ±0.72 (n = 19) IU/dL per IU/kg body weight compared to the mean highest recovery point above the pre-infusion baseline for HemofilÒM of 1.97 ±0.66 (n = 57) IU/dL per IU/kg. The clinical study of rAHF in previously treated patients (individuals with hemophilia A who had been treated with plasma derived AHF) was based on observations made on a study group of 67 patients. These individuals received 18,451 to 1,110,111 IU over the 58.2 month study period in 13,394 infusions for a total of 21,437,195 IU rAHF. These patients were successfully treated for bleeding episodes on a demand basis and also for the prevention of bleeds (prophylaxis). Spontaneous bleeding episodes successfully managed include hemarthroses, soft tissue and muscle bleeds. Management of hemostasis was also evaluated in surgeries. A total of 24 procedures on 13 patients were performed during this study. These included minor (e.g. tooth extraction) and major (e.g. bilateral osteotomies, thoracotomy and liver transplant) procedures. Hemostasis was maintained perioperatively and postoperatively with individualized AHF replacement. A study of rAHF in previously untreated patients was also performed. The study group comprised seventy-nine (79) patients of whom seventy-five (75) had received at least one infusion of rAHF. In total this cohort has been given 1,054 infusions totalling 437,126 IU rAHF. Hemostasis was appropriately managed in spontaneous bleeding episodes, intracranial hemorrhage and surgical procedures.

BIOCLATE™ (antihemophilic factor [recombinant]) DESCRIPTION Antihemophilic Factor (Recombinant), Bioclate (antihemophilic factor) TM is a glyco-protein synthesized by a genetically engineered Chinese Hamster Ovary (CHO) cell line. In culture the CHO cell line secretes recombinant antihemophilic factor (rAHF) into the cell culture medium. The rAHF is purified from the culture medium utilizing a series of chromatography columns. A key step in the purification process is an immunoaffinity chromatography methodology in which a purification matrix prepared by immobilization of a monoclonal antibody directed to factor VIII is utilized to selectively isolate the rAHF in the medium. The rAHF produced has the same biological effects as Antihemophilic Factor (Human) [AHF(Human)] and structurally has a similar combination of heterogeneous heavy and light chains as found in AHF (Human). Bioclate (antihemophilic factor) TM is formulated as a sterile, nonpyrogenic, off-white to faint yellow, lyophilized powder preparation of concentrated recombinant AHF for intravenous injection and is available in single-dose bottles which contain nominally 250, 500 and 1000 International Units per bottle. When reconstituted with the appropriate volume of diluent, it contains the following stabilizers in maximum amounts: 12.5 mg/mL Albumin (Human), 1.5 mg/mL polyethylene glycol (3350),180 mEq/L sodium, 55 mM histidine, 1.5 pg/AHF International Unit (IU) polysorbate-80 and 0.20 mg/mL calcium. Von Willebrand Factor (vWF) is coexpressed with the Antihemophilic Factor (Recombinant) and helps to stabilize it. The final product contains not more than 2 ng vWF/IU rAHF which will not have any clinically relevant effect in patients with von Willebrands disease. The product contains no preservative. Manufacturing of Bioclate (antihemophilic factor) TM is shared by Baxter Healthcare Corporation, Hyland Division and Genetics Institute, Inc. Genetics Institute produces Antihemophilic Factor Concentrate (Recombinant) (For Further Manufacturing Use) which is then formulated and packaged at Baxter Healthcare Corporation, Hyland Division. Each bottle of Bioclate (antihemophilic factor) TM is labeled with the AHF activity expressed in IU per bottle. Biological potency is determined by an in vitro assay which is referenced to the World Health Organization (WHO) International Standard for Factor VIII:C Concentrate.

PATIENT INFORMATION Although allergic type hypersensitivity reactions were not observed in any patient receiving Bioclate (antihemophilic factor) † on study, such reactions are theoretically possible. Patients should be informed of the early signs of hypersensitivity reactions including hives, generalized urticaria, tightness of the chest, wheezing, hypotension, and anaphylaxis. Patients should be advised to discontinue use of the product and contact their physician if these symptoms occur.

OVERDOSE No infrormation provided. CONTRAINDICATIONS Known hypersensitivity to mouse, hamster or bovine protein may be a contraindication to the use of Antihemophilic Factor (Recombinant) (see PRECAUTIONS).

WARNINGS No information provided. PRECAUTIONS General Identification of the clotting defect as a Factor VIII deficiency is essential before the administration of Antihemophilic Factor (Recombinant), Bioclate (antihemophilic factor) TM is initiated. No benefit may be expected from this product in treating other deficiencies. The formation of neutralizing antibodies, inhibitors, to factor VIII is a known complication in the management of individuals with hemophilia A. The reported prevalence of these anti-bodies in patients receiving plasma derived AHF is 10-20%3, 4, 5, 6, 7 10, 11, 12. These inhibitors are invariably IgG immunoglobulins, the factor VIII procoagulant inhibitory activity of which is expressed as Bethesda Units (B.U.) per mL of plasma or serum3, 4, 5, 6, 7. Over the investigational period, none of the 65 previously treated individuals, without an inhibitor at entry into the study, developed an inhibitor. In the previously untreated patient group there were 66 patients with factor VIII levels less than or equal to 2% who were tested for inhibitor after treatment with Bioclate (antihemophilic factor) TM rAHF. Of this group 12 individuals developed detectable inhibitor and of these, 3 patients showed a titer greater than 10 B.U. The true immunogenicity of Antihemophilic Factor (Recombinant), Bioclate (antihemophilic factor) TM is uncertain at this time. Patients treated with rAHF should be carefully monitored for the development of antibodies to rAHF by appropriate clinical observations and laboratory tests. Formation of Antibodies to Mouse, Hamster or Bovine Protein As Antihemophilic Factor (Recombinant), Bioclate (antihemophilic factor) TM contains trace amounts of mouse protein (maximum of 0.1 ng/IU rAHF), hamster protein (maximum of 1 ng CHO protein/IU rAHF), and bovine protein (maximum of 1 ng BSNIU rAHF), the remote possibility exists that patients treated with this product may develop hypersensitivity to these non-human mammalian proteins. Information for Patients Although allergic type hypersensitivity reactions were not observed in any patient receiving Bioclate (antihemophilic factor) TM on study, such reactions are theoretically possible. Patients should be informed of the early signs of hypersensitivity reactions including hives, generalized urticaria, tightness of the chest, wheezing, hypotension, and anaphylaxis. Patients should be advised to discontinue use of the product and contact their physician if these symptoms occur. Laboratory Tests Although dosage can be estimated by the calculations which follow, it is strongly recommended that whenever possible, appropriate laboratory tests be performed on the patients plasma at suitable intervals to assure that adequate AHF levels have been reached and are maintained. If the patients plasma AHF fails to reach expected levels or if bleeding is not controlled after adequate dosage, the presence of inhibitor should be suspected. By performing appropriate laboratory procedures, the presence of an inhibitor can be demonstrated and quantified in terms of AHF International Units neutralized by each mL of plasma or by the total estimated plasma volume. If the inhibitor is present at levels less than 10 Bethesda Units per mL, administration of adthtional AHF may neutralize the inhibitor. Thereafter the administra tion of additional AHF International Units should elicit the predicted response. The control of AHF levels by laboratory assay is necessary in this situation. Inhibitor titers above 10 Bethesda Units per mL may make hemostasis control with AHF either impossible or impractical because of the very large dose required. In addition, the inhibitor titer may rise following AHF infusion because of an anamnestic response to the AHF antigen. Carcinogenesis, Mutagenesis, Impairment of Fertility Bioclate (antihemophilic factor) † was tested for mutagenicity at doses considerably exceeding plasma concentrations of rAHF in vitro and at doses up to ten times the expected maximum clinical dose in vivo, and did not cause reverse mutations, chromosomal aberrations, or an increase in micronuclei in bone marrow polychromatic erythrocytes. Long term studies in animals have not been performed to evaluate carcinogenic potential. Pediatric Use Bioclate (antihemophilic factor) TM is appropriate for use in children of all ages, including the newborn. Safety and efficacy studies have been performed in both previously treated (n = 23) and previously untreated (n = 75) children. (See CLINICAL PHARMACOLOGY). Pregnancy Pregnancy Category C. Animal reproduction studies have not been conducted with Antihemophilic Factor (Recombinant). It is not known whether Antihemophilic Factor (Recombinant) can cause fetal harm when administered to a pregnant woman or can affect reproductive capacity. Antihemophilic Factor (Recombinant) should be given to a pregnant woman only if clearly needed.