Use of recombinant factor IX in subjects with haemophilia B undergoing surgery.

Recombinant human FIX (rFIX) was evaluated in 28 subjects, including 26 with mild, moderate, or severe haemophilia B and two haemophilia B carriers undergoing 36 surgical procedures. Preoperative rFIX dose was highly correlated with postinfusion FIX activity, r=0.61, P=0.0158. Peri- and post-operative estimated blood loss was similar to that expected in non-haemophilic individuals, and haemostasis was rated as excellent or good in 34 of 35 (97.1%) of the operative procedures. Transfusions were required in five of 36 (13.9%) procedures, including one liver transplantation, and three knee and one hip arthroplasties. Adverse events occurred in 15 of 28 (53.6%) subjects, but there were no perioperative haemorrhages, thromboembolic events, coagulation activation, viral transmission, or inhibitor formation. A transient low-responding FIX inhibitor developed in one subject preoperatively, but required no change in treatment and resolved 15 months later. Thus, rFIX was found to be safe and effective in achieving haemostasis in subjects with FIX deficiency undergoing surgery.

Human recombinant factor IX: safety and efficacy studies in hemophilia B patients previously treated with plasma-derived factor IX concentrates.

Human plasma-derived factor IX (pdFIX) concentrates are routinely used to treat patients with hemophilia B, an X-linked bleeding disorder that affects 1 in 30 000 males, but concerns remain regarding transmission of blood-borne pathogens. Therefore, the safety and efficacy of recombinant human factor IX (rFIX) were evaluated. A 20-center international trial was conducted in previously treated patients with severe or moderate (< 5 IU/dL factor IX activity) hemophilia B. Participants received rFIX for pharmacokinetic studies, treatment of or prophylaxis against hemorrhage, or surgical hemostasis, and were assessed at 3-month intervals for 2 years. Fifty-six subjects were treated. Mean incremental rFIX recovery was 0.75 IU/dL per IU/kg, 30% lower than expected for pdFIX, although the mean half-life was similar. Pharmacokinetic parameters were stable over time. Somewhat lower recoveries were seen in subjects younger than 15 years of age and in those with no detectable factor IX antigen. A total of 7362 infusions of rFIX were administered. All 1796 hemorrhages were controlled, 80.9% of which required only one rFIX infusion. Effective hemostasis was also achieved in prophylactic and surgical settings. One individual developed a low titer (1.2 Bethesda unit) transient inhibitor that spontaneously resolved. rFIX was not associated with serious adverse events, thrombogenicity, or virus transmission. rFIX is safe and effective for the treatment of hemophilia B. Despite a lower recovery compared with pdFIX, rFIX controlled hemorrhage in a wide variety of settings and may provide a safety advantage in terms of risk from blood-borne pathogens.

Clinical evaluation of B-domain deleted recombinant factor VIII in previously treated patients.

The pharmacokinetics, safety, and efficacy of B-domain deleted recombinant factor VIII (BDDrFVIII) were evaluated in patients with hemophilia A. In an initial 12-month study with subsequent yearly extensions over a 5-year period, 113 previously treated patients (PTPs) received on-demand and/or prophylactic treatment with BDDrFVIII, including treatment during surgery, if required. Half-life and recovery of factor VIII activity remained unchanged over the study period. The mean elimination half-life was 10.5 +/- 2.6 hours at baseline and 10.4 +/- 3.3 hours at month 12. A total of 7,310 hemorrhages occurred for patients who received on-demand treatment, with 71% resolving after a single infusion. Of the 11,655 rated infusions given for hemorrhages, 92% were rated by investigators and patients as providing an "excellent" or "good" response. These results are consistent with efficacy data from other trials using recombinant factor VIII products. During the prophylactic period, 12% of patients experienced no bleeding episodes, and 17% of the patients had no on-demand treatment. The mean dose was 28 IU/kg for prophylactic treatment and 30 IU/kg for on-demand treatment. The efficacy of administering BDDrFVIII in conjunction with surgery was assessed to be "very useful" or "useful" in all cases. Few adverse events were reported, and only one patient developed inhibitors to factor VIII activity. The results show that BDDrFVIII provides a safe and effective treatment of hemophilia A when given as on-demand therapy, in routine or intermittent prophylaxis, or during surgery.

Clinical evaluation of B-domain deleted recombinant factor VIII in previously untreated patients.

The safety and efficacy of B-domain deleted recombinant factor VIII (BDDrFVIII) were evaluated in previously untreated patients (PUPs) with severe hemophilia A. In an open-label multicenter study, 101 PUPs received routine prophylactic and/or on-demand treatment with BDDrFVIII, including treatment related to surgery for 50 exposure days for up to 5 years. The pharmacokinetic measurements (ie, elimination half-life and in vivo mean recovery) assessed at baseline and 12 months were stable for BDDrFVIII over time. A total of 1,362 hemorrhages occurred. Ninety-two percent (1,258/1,362) of bleeding episodes resolved after three infusions or fewer. Of the 2,375 infusions rated by investigators, 93% (2,215/2,375) were rated as providing an "excellent" or "good" response. Twenty-seven patients received routine prophylactic treatment, which significantly reduced breakthrough bleeding episodes by twofold when compared with patients who were treated on-demand. Administration in conjunction with 40 surgical procedures showed no adverse effects, and the overall assessment was either "very useful" or "useful." The mean dose was 56 IU/kg for routine primary prophylaxis and 53 IU/kg for on-demand therapy for bleeding episodes in patients who were assessed to be inhibitor-free at the time of infusion. Thirty-two percent of patients developed inhibitors. Of these, 16 patients were high responders (peak titer > or = 5 Bethesda units [BU]). The inhibitor risk was comparable to that seen with full-length recombinant products. BDDrFVIII was found to be effective, safe, and well tolerated.

A clinical evaluation of genetic stability.

Mutation in a genetically engineered cell line has not been shown to have been responsible for adverse clinical reactions in a currently licensed biotechnology product. There exists, however, the theoretical possibility that mutations in the production cell line could ultimately lead to patient exposure to aberrant proteins which could result in unanticipated or deleterious effects. The clinical trials of recombinant antihaemophilic factor, a large complex glycoprotein, which is administered chronically, offered a unique opportunity to explore this theoretical concern. In this retrospective analysis of patient data, evidence for unanticipated or adverse events which could possibly be attributed to mutations in the genetically engineered cell line was sought. Extensive analysis of a variety of patient data such as the efficacy, alterations in pharmacokinetic parameters, and inhibitor formation, gave no support for concern over host cell mutation. While this retrospective analysis cannot absolutely exclude the possibility of mutational events, those clinical data in combination with the product characterization information indicate that for this recombinant product, mutation is a highly improbable event.

Treatment of hemophilia A with a highly purified factor VIII concentrate prepared by anti-FVIIIc immunoaffinity chromatography.

To reduce the risk of pathogenic virus transmission associated with the therapeutic administration of plasma-derived anti-hemophilic factor (FVIIIc), a process utilizing anti-FVIIIc immunoaffinity chromatography to isolate FVIIIc has been developed. In addition, the starting cryoprecipitate solution has been treated with an organic solvent/detergent mixture to inactivate lipid-enveloped viruses. A final ion exchange chromatography step is used to further remove contaminants, e.g., anti-FVIIIc antibody, potentially leached with FVIIIc during the immunoaffinity step. The purified FVIII is stabilized for lyophilization and storage by the addition of human albumin. The monoclonal anti-FVIIIc antibody used in the immunoaffinity step of the process is not detectable in the final preparation. Viral reduction studies performed at specific steps of the process demonstrate that 11 logs of human immunodeficiency virus (HIV) and greater than 4-5 logs of other lipid-enveloped viruses are inactivated within the first 30 s of exposure to the solvent/detergent mixture and 4-5 logs of various model viruses, e.g. Endomyocarditis virus (EMC), are physically removed during washing of the immunoaffinity column. The lyophilized product is reconstituted using sterile water in a matter of seconds. The pharmacokinetics of Hemofil M were compared to those obtained using a standard heat-treated concentrate (Hemofil CT) in five severe factor VIII deficient hemophiliacs in a randomized, cross-over study. No statistically significant differences were observed in mean half life (p greater than 0.6) or median recovery (p = 0.4) between the two preparations. No clinically significant adverse effects were observed in patients receiving either FVIII preparation.(ABSTRACT TRUNCATED AT 250 WORDS)

Safety of an intravenous immunoglobulin preparation: lack of seroconversion for human immunodeficiency virus antibodies.

A retrospective analysis of 18 patients who had received a human intravenous immunoglobulin (IGIV) preparation was undertaken to ascertain the safety of this preparation with respect to transmission of human immunodeficiency virus (HIV), the virus that causes the acquired immune deficiency syndrome (AIDS). Patients were followed up by means of periodic enzyme-linked immunosorbent assay (ELISA) for the presence of circulating antibodies against HIV; a negative ELISA was evidence that HIV had not been transmitted to the recipients of IGIV. Results in 16 patients were negative, and two patients were determined to have had false-positive ELISAs because the Western blot test was negative for seroconversion. It is thus concluded that the IGIV product tested has little or no potential for transmitting HIV.