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Frequently asked questions

Speaking with your Shire sales representative is the best way to get all of the information you need when considering prescribing OBIZUR, Antihemophilic Factor (Recombinant), Porcine Sequence. However, below you can find answers to possible questions you may have about OBIZUR.

What is OBIZUR?

  • OBIZUR, Antihemophilic Factor (Recombinant), Porcine Sequence, is a recombinant DNA derived, antihemophilic factor indicated for the treatment of bleeding episodes in adults with acquired hemophilia A.1
  • Limitations of Use1:
    • Safety and efficacy of OBIZUR has not been established in patients with baseline anti-porcine factor VIII inhibitor titer greater than 20 BU
    • OBIZUR is not indicated for the treatment of congenital hemophilia A or von Willebrand disease
  • Additional information.

How was OBIZUR studied?

  • The safety and efficacy of OBIZUR was investigated in the first-ever prospective, global, open-label study in acquired hemophilia A (N=29).1 The study was conducted in patients diagnosed with acquired hemophilia A (AHA) with autoimmune inhibitory antibodies to human factor VIII, experiencing serious bleeding requiring hospitalization.1 An initial dose of 200 units per kg of OBIZUR was administered.1 Patients were assessed approximately 30 minutes and approximately 3 hours after the initial dose, and dosing was titrated based on clinical improvement and FVIII activity levels.1 The primary endpoint was a positive response to OBIZUR treatment at 24 hours.1 Additional information.

How effective is OBIZUR?

  • Twenty-eight patients had a positive response to treatment at 24 hours after initial dosing, as assessed by the primary investigator.1 One patient was eliminated from the efficacy evaluation when it was determined that the patient did not have AHA.1

    A hemostatic response was assessed by the study site investigator at specified time points after initiation of OBIZUR treatment using a pre-specified rating scale that was based on subjective clinical assessments combined with objective factor VIII activity levels achieved.1

    OBIZUR demonstrated rapid results, as a positive response was observed in 95% of bleeds within 8 hours (19/20) and 100% of bleeds within 16 hours (18/18) post-infusion.1 Overall, evaluations of eventual successful treatment of the initial bleed showed an 86% success rate (24/28).1 Of these patients, 94% were treatment naïve (16/17) and 73% were previously treated (8/11).1 Additional information.

What is the OBIZUR safety profile?

  • Common adverse reactions observed in greater than 5% of subjects in the clinical trial were development of inhibitors to porcine factor VIII.1

    There were no serious adverse reactions (ARs) reported with OBIZUR use in the clinical study.3 There were no related thrombotic events reported.3

Did any patients acquire anti-porcine factor VIII antibodies?

  • Of the 29 patients treated with OBIZUR, 10 patients had detectable anti-porcine factor VIII antibodies at baseline.1 Of these 10 patients, 2 experienced an increase in titer of inhibitory antibodies against antihemophilic factor (recombinant), porcine sequence in the clinical study.1 Inhibitory antibodies against OBIZUR were measured using a Bethesda assay-based method.1 Additional information.

How are FVIII levels measured?

  • Post-administration FVIII activity levels were measured using a one-stage clotting assay or a one-stage clotting assay to confirm that adequate factor VIII levels were achieved and maintained.1 Additional information.

What is the dosing of OBIZUR?

  • The initial dose is 200 units per kg, with subsequent dosing to maintain trough levels.1 FVIII activity levels should be monitored to confirm adequate levels are achieved and maintained.1 Titrate dose and interval based on FVIII recovery levels to maintain target levels.1 The median number of OBIZUR infusions in the clinical study was 3 (median dose 200 U/kg) in the initial 24 hours.1 Additional information.

How is OBIZUR supplied and stored?

  • OBIZUR is available in kits with single-use vials. Each kit contains one package insert and the appropriate number of each of the following1:
    • Single-use vials of OBIZUR
    • 1 mL Sterile Water for Injection prefilled syringes
    • Vial adapter with filter
  • Storage and Handling1
    • Refrigerated temperature: 2°C to 8°C (36°F to 46°F)
    • Do not freeze
    • Do not use beyond the expiration date printed on the carton or vial
  • Additional information.

In which patients was OBIZUR studied?

  • OBIZUR was studied in the following patient populations1:
    • 19 males and 10 (34%) females
    • 10 patients between the ages of 40 and 65, and 19 patients ≥65 years old
    • Average patient age was 70 years
    • Patients varied in race:
      • 18 Caucasians
      • 6 African-Americans
      • 5 Asians
  • Additional information.

How is AHA diagnosed?

  • Perform a mixing study with normal plasma incubated for 1 to 2 hours at 37°C.6 The mixing test is time- and temperature-dependent because autoantibodies do not inhibit FVIII immediately in normal plasma, and performing the test without proper incubation or temperature may result in missing an AHA diagnosis.6 Additional information.