"The US Food and Drug Administration (FDA) today approved asfotase alfa (Strensiq, Alexion Pharmaceuticals) as the first-ever therapy for patients who develop hypophosphatasia, a rare metabolic bone disorder, in childhood.
Helixate® FS Antihemophilic Factor (Recombinant) is intended for the treatment of bleeding disorders arising from a deficiency in FVIII. This deficiency should be proven prior to administering Helixate FS (antihemophilic factor (recombinant)) .
The development of circulating neutralizing antibodies to FVIII may occur during the treatment of patients with hemophilia A. Inhibitor formation is especially common in young children with severe hemophilia during their first years of treatment, or in patients of any age who have received little previous treatment with FVIII. Nonetheless, inhibitor formation may occur at any time in the treatment of a patient with hemophilia A. Patients treated with any AHF preparation, including Helixate FS (antihemophilic factor (recombinant)) , should be carefully monitored for the development of antibodies to FVIII by appropriate clinical observation and laboratory tests, according to the recommendation of the patient's hemophilia treatment center.
Among patients treated with antihemophilic factor concentrates, cases of hypotension, urticaria, and chest tightness in association with hypersensitivity reactions have been reported in the literature.11-13 Very rare cases of allergic and anaphylactic reactions have been reported with the predecessor product HELIXATE® Antihemophilic Factor (Recombinant), particularly in very young patients or patients who have previously reacted to other FVIII concentrates (see ADVERSE REACTIONS - Post-marketing experience). Serious anaphylactic reactions require immediate emergency treatment with resuscitative measures such as the administration of epinephrine and oxygen.
Formation of Antibodies to Mouse and Hamster Protein
Assays to detect seroconversion to mouse and hamster protein were conducted on all patients in clinical studies. No patient has developed specific antibodies to these proteins after commencing study, and no animal protein associated serious allergic reactions have been observed with rFVIII-FS infusions. Although no such reactions were observed, patients should be made aware of the possibility of a hypersensitivity reaction to mouse and/or hamster protein, and alerted to the early signs of such a reaction (e.g., hives, localized or generalized urticaria, wheezing, and hypotension). Patients should be advised to discontinue use of the product and contact their physician if such symptoms occur.
Carcinogenesis, Mutagenesis, and Impairment of Fertility
In vitro evaluation of the mutagenic potential of rFVIII failed to demonstrate reverse mutation or chromosomal aberrations at doses substantially greater than the maximum expected clinical dose. In vivo evaluation of rFVIII in animals using doses ranging between 10 and 40 times the expected clinical maximum also indicated that rFVIII does not possess a mutagenic potential. Long-term investigations of carcinogenic potential in animals have not been performed.
Helixate® FS Antihemophilic Factor (Recombinant) is appropriate for use in pediatric patients of all ages, including neonates, infants, children, and adolescents. Safety and efficacy studies have been performed in previously untreated and minimally treated pediatric patients (n=62). Helixate FS (antihemophilic factor (recombinant)) is similar to HELIXATE in its biological activity and may be used in pediatric patients in the same manner as HELIXATE.
Clinical studies with Helixate FS (antihemophilic factor (recombinant)) did not include sufficient numbers of patients aged 65 and over to be able to determine whether they respond differently from younger patients. However, clinical experience with HELIXATE and other AHF products has not identified differences between the elderly and younger patients. As with any patient receiving Helixate FS (antihemophilic factor (recombinant)) , dose selection for an elderly patient should be individualized.
Pregnancy Category C
Animal reproduction studies have not been conducted with Helixate FS (antihemophilic factor (recombinant)) . It is also not known whether Helixate FS (antihemophilic factor (recombinant)) can cause fetal harm when administered to a pregnant woman or affect reproduction capacity. Helixate FS (antihemophilic factor (recombinant)) should be used during pregnancy and lactation only if clearly indicated.
11. Brettler DB, Forsberg AD, Levine PH, et al: The use of porcine factor VIII concentrate (Hyate:C) in the treatment of patients with inhibitor antibodies to factor VIII. A multicenter US experience. Arch Intern Med 149(6): 1381-5, 1989.
12. Eyster ME, Bowman HS, Haverstick JN: Adverse reactions to factor VIII infusions. Ann Intern Med 87(2):248, 1977.
13. Brettler DB, Levine PH: Factor concentrates for treatment of hemophilia: which one to choose? Blood 73(8):2067-73, 1989.This monograph has been modified to include the generic and brand name in many instances.
Last reviewed on RxList: 1/30/2009
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