Factor VII light chain-targeted lidamycin shows intensified therapeutic efficacy for liver cancer.

The overexpression of tissue factor (TF) observed in numerous cancer cells and clinical samples of human cancers makes TF an ideal target for cancer therapy. The purpose of this study is to develop a TF-targeting energized fusion protein hlFVII-LDP-AE, which is composed of a human Factor VII light chain (hlFVII) as the targeting domain conjugated to the cytotoxic antibiotic lidamycin (LDM, LDP-AE) as the effector domain. The potential efficacy of hlFVII-LDP-AE for cancer therapy was tested in vitro by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and colony formation assays and in vivo with a BALB/c nude mouse xenograft model of human liver cancer line HepG2. The inhibitory concentration (IC(50)) value of hlFVII-LDP-AE varied from 0.15 to 0.64 nM for the various human tumor lines. hlFVII-LDP-AE showed a tumor growth inhibition rate of 90.6% at the dose of 0.6 mg/kg in in vivo animal experiments. The mechanism through which hlFVII-LDP-AE inhibits tumor growth also was determined by Hoechst 33342 staining and Tdt-mediated dUTP nick-end labeling (TUNEL) assay. hlFVII-LDP-AE causes tumor cell death through inducing chromatin condensation and cleavage of genomic DNA. These findings suggest that the hlFVII-LDP-AE protocol is efficacious and tolerated in the mouse model of human liver cancer HepG2 and has clinical applicability for treating cancer patients.

The evidence for the use of recombinant human activated factor VII in the treatment of bleeding patients with quantitative and qualitative platelet disorders.

There are increasing reports suggesting that high-dose recombinant human activated factor VII (rFVIIa) is effective in the treatment and prevention of bleeding in patients with quantitative and qualitative platelet disorders. These clinical observations are supported by evidence that FVIIa binds weakly to activated platelet surface and at high concentration improves thrombin generation. In experimental models, this improved thrombin generation enhances platelet adhesion in thrombocytopenic conditions and enhances adhesion and aggregation of platelets lacking glycoprotein IIbIIIa (integrin alpha(IIb)beta(3)), characteristic of the qualitative platelet disorder Glanzmann thrombasthenia (GT). There is a need for clinical trials to confirm the safety and efficacy of rFVIIa in patients with various quantitative and qualitative platelet defects, either by itself or in combination with other hemostatic agents such as platelet transfusion. Pending the availability of such data, rFVIIa may be considered in severe bleeding in thrombocytopenia and GT patients with platelet antibodies and refractory to platelet transfusions and other standard treatments. An international survey suggests that rFVIIa at about 90 microg/kg every 2 hours for 3 or more doses could be used for GT patients with severe bleeding, but confirmation by larger studies is needed. For GT patients undergoing surgery and for treatment and prevention of bleeding in thrombocytopenic patients, the optimal rFVIIa regimen remains to be defined.

Recombinant activated factor VII in treatment of bleeding complications following hematopoietic stem cell transplantation.

BACKGROUND: Bleeding is a common complication following hematopoietic stem cell transplantation (HSCT) and standard hemostatic treatment is often ineffective. We conducted a multicentre, randomized trial of the efficacy and safety of activated recombinant factor VII (rFVIIa, NovoSeven) in the treatment of bleeding following HSCT. METHODS: 100 patients with moderate or severe bleeding (52 gastrointestinal; 26 hemorrhagic cystitis; seven pulmonary; one cerebral; 14 other) were included from days +2 to +180 post-transplant (97 allogeneic; three autologous) to receive seven doses of rFVIIa (40, 80 or 160 microg kg(-1)) or placebo every 6 h. The primary efficacy endpoint was the change in bleeding score between the first administration and 38 h. RESULTS: No significant effect of increasing rFVIIa dose was observed on the primary endpoint. A post hoc analysis comparing each rFVIIa dose with placebo showed that 80 microg kg(-1) rFVIIa improved the bleeding score at the 38 h time point (81% vs. 57%, P = 0.021). This effect was not seen at 160 microg kg(-1). There were no differences in transfusion requirements across dose groups. There was no trend in the type or number of severe adverse events observed. Six thromboembolic events were observed in the active treatment groups: three during, and three following the 96-h observation period. CONCLUSIONS: Despite no overall effect of rFVIIa treatment on primary endpoint, post hoc analysis showed an improvement in the control of bleeding for 80 microg kg(-1) rFVIIa vs. standard hemostatic treatment. The heterogeneity of the population may have contributed to the lack of an increasing effect with increased dose. Further trials should focus upon identifying the patient populations that may benefit from treatment with rFVIIa.

Intestinal surgery with activated recombinant factor VII prophylaxis in patients with haemophilia A and high responding inhibitors: a report of five cases.

Five patients with severe haemophilia A and high responding inhibitors underwent laparoscopic or open surgery on the digestive tract (appendicectomy, cholecystectomy, partial colectomy, or haemorrhoidectomy) with recombinant activated factor VII (rFVIIa) prophylaxis. rFVIIa was administered at a dose of 92-127 mug/kg prior to surgery and then every 2 h for 18-56 h before increasing the dosing interval. One patient was switched to a continuous infusion after 48 h of rFVIIa boluses. rFVIIa treatment lasted between 5 and 14 days in four patients, with good or excellent efficacy (total dose, 3.13-9.28 mg/kg). The fifth patient, who underwent surgery for prolapsed haemorrhoids, bled on day 6 and day 10 after the procedure, despite a satisfactory prothrombin time and factor VII coagulant level. The rFVIIa dose regimen was increased after the second bleeding episode, then the bleeding rapidly ceased after this modification to the treatment regimen. The total dose of rFVIIa used was 12.65 mg/kg, and treatment lasted 17 days. Antifibrinolytic treatment was used concomitantly in all five patients. Clinical and biological tolerability was excellent, and no increase in the anti-factor VIII inhibitor titre was observed. These results suggest that rFVIIa prophylaxis is effective in haemophilia A patients with factor VIII inhibitors who are undergoing elective or emergency intestinal surgery. Further studies are required to optimize the dose regimen and treatment period according to the surgical indication and technique.

Recombinant activated factor VII in cardiac surgery.

Adult cardiac surgery has an incidence of 1-1.25 million procedures per year. Overall costs are in the range of 50 billion US dollars per year and are increasing. Included in these costs is an increasing burden from the use of blood and blood products. The central haemostatic problems associated with cardiac surgery are impaired platelet function associated with pre-operative medication and cardiopulmonary bypass, consumption of platelets, dilution of coagulation proteins and triggering of fibrinolysis. Anecdotal data suggest that recombinant activated factor VII (rFVIIa) has a possible role in cardiac surgery, but randomized, controlled trials are required to confirm this potential. We have undertaken a prospective, randomized, placebo-controlled trial in adult cardiac surgery with a high risk of serious haemorrhage. Drug (rFVIIa) or placebo is given after cardiopulmonary bypass and following the administration of protamine. The primary endpoints of the study are use of blood and blood products. Secondary endpoints are blood loss, length of stay in the intensive care unit and in the hospital, and survival. This study will give us further information on the potential efficacy and safety of rFVIIa in cardiac surgery.

Recombinant activated factor VII in patients at high risk of bleeding.

Currently, recombinant activated factor VII (rFVIIa) (NovoSeven) is indicated for the treatment of spontaneous and surgical bleeding in congenital haemophilia A and B patients with inhibitors to factors VIII (FVIII) and IX (FIX) >5 Bethesda units (BU) worldwide, and in patients with acquired haemophilia, congenital FVII deficiency and Glanzmann's thrombasthenia in Europe. Until April 2003, almost three-quarters of a milion doses of rFVIIa have been administered proving its efficacy and excellent safety record. According to results from initial clinical trials and a large number of case reports, the rFVIIa may be effective not only in treating haemophilia patients but also in treatment of bleeding in patients on oral anticoagulation or heparin, patients with liver diseases, von Willebrand disease (vWD), thrombocytopenia, various platelet defects, congenital or acquired deficiency of FVII, and in subjects without any pre-existing coagulopathy with diffuse life-threatening bleeding triggered by surgery or trauma. This review will briefly summarize rFVIIa mode of action in haemostasis, the current clinical experience with rFVIIa and focus on the alternative use of rFVIIa in patients at the high risk of bleeding in both spontaneous cases and clinical trials reports.

A prospective study of recombinant activated factor VII administered by continuous infusion to inhibitor patients undergoing elective major orthopaedic surgery: a pharmacokinetic and efficacy evaluation.

After surgery in haemophilia, haemostasis is difficult to maintain in the presence of an antifactor VIII antibody. This study assessed the pharmacokinetics of recombinant activated factor VII (rFVIIa) and its efficacy in securing post-operative haemostasis in haemophiliacs with inhibitors. Continuous infusion of rFVIIa was evaluated for elective major orthopaedic surgery in nine patients with neutralizing antibodies to FVIII and at high risk of bleeding. After an initial preoperative bolus of 90 micro g/kg, rFVIIa was infused at a fixed rate of 50 micro g/kg/h for a median of 20 d (range 7-20 d). The median plasma FVII coagulant activity (FVII:C) at 24 h, 72 h and 20 d after surgery was 38 IU/ml (range 22-169 IU/ml), 45 IU/ml (range 17-88 IU/ml) and 31 IU/ml (range 27-46 IU/ml) respectively. The median plasma FVIIa:C at the same time points was 51 (range 24-211), 63 (range 22-99) and 44 (range 28-76) IU/ml respectively. Median total rFVIIa clearance remained stable during the rFVIIa continuous infusion period and was 40 (range 9-70), 34 (range 17-86) and 48 (range 32-55)ml/kg/h at the end of 24 h, 72 h and 20 d infusion respectively. Post-operatively, there were bleeds in six patients, which settled readily after a single bolus of rFVIIa (60 micro g/kg). There was a good clinical outcome for all patients. These data indicate that rFVIIa infusion at 50 micro g/kg/h achieves continuous plasma FVII procoagulant activity in excess of 30 IU/ml (12-15 nmol/l) and provides adequate haemostatic control for inhibitor patients during major orthopaedic surgery.

The evidence behind inhibitor treatment with recombinant factor VIIa.

Over the past 10 years considerable use has been made of recombinant factor VIIa (rFVIIa) for the treatment of patients with inhibitors to coagulation factors. During this time, its place in the management of acute bleeds and surgery has become better defined. Although pharmacokinetic studies report the half-life of rFVIIa as 2.7 h, there is considerable intersubject variability. Moreover, rFVIIa is cleared more rapidly in children than in adults. Assays for the measurement of rFVIIa plasma levels are not readily available in clinical diagnostic laboratories, although there is evidence that plasma FVII:C levels, measured by a one-stage prothombin-based assay, reflect the plasma concentration of rFVIIa:C. The level of FVII:C required to achieve haemostasis in different clinical circumstances remains uncertain. In order to overcome the logistic difficulties of repeated frequent bolus injections, and potentially to minimise usage, administration of rFVIIa by continuous infusion has been reported. However, there is some uncertainty as to whether continuous infusion of rFVIIa has similar therapeutic efficacy to an equivalent total dose administered by bolus injections. The extensive clinical experience with rFVIIa in haemophilic patients with inhibitors has been recorded in descriptive accounts of the Compassionate Use Programme and the Emergency Use Study. On the basis of the apparent clinical efficacy and safety reported in these studies, prospective randomised trials of different dose regimens have been undertaken for the treatment of acute bleeds and surgery. These have helped to define the minimum dose needed to achieve haemostasis. There remains considerable uncertainty about the minimal effective dose and appropriate duration of therapy in different clinical circumstances. There is therefore a need for the development of evidence-based guidelines for the use of rFVIIa in bolus and continuous infusion regimens in different settings, and for the therapeutic value of measuring plasma concentrations of rFVIIa, to facilitate the optimal use of this product. Furthermore, additional randomised clinical trials will help ensure that rFVIIa is used in the most clinically and cost effective way.

Perioperative pharmacokinetics of factor VII concentrate during liver surgery in a patient with congenital factor VII deficiency: an individual mathematical model.

A patient with congenital factor VII deficiency (baseline activity, 7%) underwent surgery for hepatocellular carcinoma. No literature reference was found concerning the management of this coagulation defect in patients requiring liver surgery. We report one such case, with special reference to the peri-operative management of factor VII replacement therapy and the pharmacokinetic behavior of factor VII. As a result of accidental suprahepatic vein lesion, a bleeding episode occurred. This was associated with an increase in factor VII clearance and volume of distribution values from 1.30 to 3.85 l/h, and from 6.51 to 13.2 l, respectively. After surgery, the patient continued to receive the concentrate every 8 h during the first nine post-operative days. No post-operative bleeding or thrombotic event was observed. The patient was discharged in good condition.