Ineffective off-label use of recombinant activated factor VII in a case of bone-marrow transplantation-related gastrointestinal bleeding

Evaluation of morning glory (Jacquemontia tamnifolia (L.) Griseb) leaves for antioxidant, antinociceptive, anticoagulant and cytotoxic activities

BACKGROUND

The present study was planned to investigate the phytochemical, antioxidant, antinociceptive, anticoagulant and cytotoxic activities of the Jacquemontia tamnifolia (L.) Griseb leaf methanol extract (MExJT) in the laboratory using both in vitro and in vivo methods.

METHODS

Phytochemical values, namely, total phenolic and flavonoid contents, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging effect and FeCl3 reducing power effects, were studied by established methods. In vivo antinociceptive activity was performed by acidic acid-induced writhing test and formalin-induced pain test on Swiss albino mice at doses of 125, 250 and 500 mg/kg body weight. The clot lysis and brine shrimp lethality bioassay in vitro were used to evaluate the thrombolytic and cytotoxic activities of the plant extract, respectively.

RESULTS

Phytochemical screening illustrates the presence of tannins, saponins, flavonoids, gums and carbohydrates, steroids, alkaloids and reducing sugars in the extract. The results showed the total phenolic content (146.33 g gallic acid equivalents/100 g extract) and total flavonoid content (133.33 g quercetin/100 g). Significant (p<0.05) IC50 values compared to respective standards were recorded in DPPH radical scavenging (289.5 μg/mL) and FeCl3 reduction (245.2 μg/mL). The antinociceptive effect was evaluated in the acetic acid-induced writhing test and formalin-induced pain models in Swiss albino mice with doses of 125, 250 and 500 mg/kg body weight. Significant (p<0.05) inhibition (72.87±2.73%) of writhing response compared to diclofenac sodium was achieved by 500 mg/kg body weight. The extract also significantly inhibited the licking response in both the early phase (51.59±1.57%, p<0.05) and the late phase (64.82±1.87%, p<0.05) in the formalin-induced writhing test. MExJT also showed (38.10±1.79%) clot lytic activity in the thrombolytic test and cytotoxicity with an LC50 value of 31.70 μg/mL in the brine shrimp lethality bioassay.

CONCLUSIONS

The plant is a potential source of antioxidants and might have one or more secondary metabolite(s) with central and peripheral analgesic activity. The results also demonstrate that MExJT has moderate thrombolytic and lower cytotoxic properties that may warrant further exploration.

Assessment of the antioxidant, thrombolytic, analgesic, anti-inflammatory, antidepressant and anxiolytic activities of leaf extracts and fractions of Tetracera sarmentosa (L.) Vahl

BACKGROUND

The plant under investigation (Tetracera sarmentosa) is a dicotyledonous flowering plant and belongs to the family Dilleniaceae. The goal of our investigation was to determine whether the leaf extracts of this plant held any significant medicinal properties.

METHODS

Leaves of T. sarmentosa were extracted with pure ethanol (EETS) and methanol (METS), and then methanol extract fractioned with n-hexane (NHFMETS) and chloroform (CHFMETS). The extracts and fractions were tested for antioxidant activity, which was measured by using qualitative and quantitative procedures. Thrombolytic activity was evaluated by the clot lysis test. Analgesic activity was evaluated employing the acidic acid-induced writhing test, the formalin-induced paw licking test and tail immersion on Swiss albino mice. The anti-inflammatory activity test was studied using the paw edema test. Forced swimming, tail suspension, elevated plus maze and hole board model tests were used to evaluate neuropharmacological activity.

RESULTS

All the extracts and fractions possessed antioxidant effects. All the extracts, fractions and streptokinase exhibited significant (p<0.0001) clot lysis. The extracts and fractions produced significant analgesic effects as evaluated by the acetic acid writhing test, the formalin-induced paw licking test and the tail immersion method. Similarly, carrageenan-induced inflammation was significantly antagonized by the treatments. The extracts and fractions also significantly showed neuropharmacological (antidepressant and anxiolytic) effects.

CONCLUSIONS

The overall results suggested that this plant deserves further investigation to isolate the active compounds which are responsible for these activities and to establish the mechanism of action.

[Analysis of clinical efficacy of recombinant activated factor Ⅶ on bleeding in patients with hematologic disorders]

Objective: To investigate the treatment efficacy of recombinant activated factor Ⅶ (rFⅦa) for bleeding among patients with hematologic disorders. Methods: A total of 38 times of bleeding in 31 patients with hematological disease treated with rFⅦa were analyzed retrospectively. Results: The clinical effective rate of rFⅦa for bleeding management in acquired hemophilia A (AHA) patients/hemophilia patients with inhibitor, acute promyelocytic leukemia (APL) patients and patients with non-APL leukemia was 90% (9/10) , 71.4% (5/7) and 60.0% (3/5) , respectively, which was higher than that in patients following HSCT (30.8%) . The clinical effective rate of rFⅦa for patients with bleeding score of 2 (100.0%) was higher than that with 3 (66.7%) and 4 (54.1%) . The effective rate of rFⅦa was 25.0% (2/5) in 5 patients with cerebral hemorrhage, 66.7% (6/9) in 9 patients with hematuria and 41.7% in 12 patients with gastrointestinal hemorrhage. The curative effect for 3 patients with joints and muscle bleeding and 5 patients with skin, nasal, pharyngeal and gum bleeding was excellent. Following HSCT, among patients with bleeding score of 4 points, high dose and repeated use of rFⅦa did not necessarily achieve a good effect. Among AHA/hemophilia patients with inhibitors and patients with acute leukemia who had bleeding score of 4 points, the use of low dose FⅦa could achieve good therapeutic effect, however the efficacy of lowest dose (22.5 μg/kg) rFⅦa was poor. Conclusions: The hemostasis efficacy of rFⅦa is affected by various factors such as diseases, bleeding sites, bleeding score and so on. The use of rFⅦa can achieve good efficacy for bleeding management in AHA patients/hemophilia patients with inhibitor, APL patients and patients with non-APL leukemia. However the efficacy of rFⅦa for bleeding of patients after HSCT is poor. Early use of rFⅦa is important for successful hemostatic treatment. Management of underlying condition is as important as hemostatic treatment.

Antithrombotic and cytotoxic activities of four Bangladeshi plants and PASS prediction of their isolated compounds

BACKGROUND

This study aims to investigate whether tested organic extracts possess antithrombotic properties with minimal or no toxicity and to predict the activity of some of their isolated compounds.

METHODS

An in vitro thrombolytic model was used to check the clot lysis effect of four Bangladeshi herbal extracts viz., roots of Curculigo recurvata W.T. Aiton (Satipata), leaf of Amorphophallus bulbifer Roxb. (Olkachu), leaf of Phyllanthus sikkimensis Muell. Arg., and whole plant of Thunbergia grandiflora Roxb. (Nillata) using streptokinase as a positive control and water as a negative control. Cytotoxicity was screened by brine shrimp lethality bioassay using vincristine sulfate as positive control. In silico prediction of activity spectra for substances (PASS) prediction was applied for phytoconstituents, namely, nyasicoside, glucomannan, grandifloric acid, serine, and alanine.

RESULTS

Using an in vitro thrombolytic model, C. recurvata, A. bulbifer, P. sikkimensis, and T. grandiflora showed 28.10±1.64%, 42.47±1.96%, 32.86±1.92%, and 25.51±1.67% of clot lysis, respectively. Reference drug streptokinase exhibited 75.00±3.04% clot lysis. Examined herbs showed significant (p<0.001) percentage (%) of clot lysis compared to negative control. In brine shrimp cytotoxic assay, C. recurvata, A. bulbifer, P. sikkimensis, and T. grandiflora showed LC50 values 210.64±3.44, 98.51±1.47, 187.29±2.01, and 386.43±3.02 μg/mL, respectively, with reference to vincristine sulfate (LC50 0.76±0.04). PASS predicted that examined phytoconstituents have a wide range of biological activity.

CONCLUSIONS

Through our study it was found that A. bulbifer and P. sikkimensis could be considered as very promising and beneficial thrombolytic agents.

Fibrinolytic enzyme production by newly isolated Bacillus cereus SRM-001 with enhanced in-vitro blood clot lysis potential

The discovery of plasmin-like microbial fibrinolytic enzymes having high specificity and negligible side effects is crucial for thrombolytic therapy. Herein, we report one such extra-cellular fibrinolytic enzyme producing Bacillus cereus SRM-001 isolated from the blood-laden soil of a chicken dump yard. The potency of the enzyme was established with fibrin plate assay and in-vitro blood clot lysis assay. The shake-flask operating parameters and media composition were optimized for maximizing the productivity of the enzyme. The operating parameters, pH 7, 37°C, 1% inoculum volume and 24 h inoculum age, were found to be the optimum. The levels of media components, corn flour (0.3% w/v), soyabean powder (1.9% w/v) and MnSO4 (11.5 mM) were optimized by statistical analysis using Box-Behnken design derived RSM. This resulted in an almost 1.8 fold increase in fibrinolytic enzyme productivity. The 3D response surface plots showed soyabean powder and MnSO4 to be the key ingredients for enhancing the enzyme productivity, whereas corn flour had a marginal effect. The in-vitro blood clot lysis assay conducted at near physiological pH 7 at 37°C showed the enzyme to be a potential therapeutic thrombolytic agent.

Use of recombinant factor VIIa in uncontrolled gastrointestinal bleeding after hematopoietic stem cell transplantation among patients with thrombocytopenia

Background and Objective:

Recombinant-activated factor VII (rVIIa) is a vitamin K-dependent glycoprotein that is an analog of the naturally occurring protease. It has an off-label use to control life-threatening bleeding that is refractory to other measures and was shown to decrease transfusion requirements. Gastrointestinal (GI) bleeding is a severe complication following hematopoietic stem cell transplantation (HSCT) in patients with thrombocytopenia, while hemostatic measures based on antifibrinolytic or transfusion therapy may not always be successful. The present study investigated the treatment with rFVIIa in severe GI bleeding among thrombocytopenia patients undergoing HSCT.

Methods:

rFVIIa was given as a single dose of 60μg/kg in patients with GI bleeding following hematopoietic stem cell transplantation (HSCT).

Results:

Among all patients enrolled, 12 (75%) of 16 patients obtained a response, of which 5 achieved a complete response and 7 achieved a partial response. The 4 remiaing patients (25%) had no response. Nine patients (56.3%) died in a follow-up of 90 days. No thromboembolic events wereassociated with the drug administration occurred.

Conclusions:

Our study showed that rFVIIa may represent an additional therapeutic option in such cases.

Platelet activation: ultrastructure and morphometry in platelet-rich plasma of horses

This study was conducted to investigate the activation ability of the platelet-rich plasma (PRP) by pharmacological agents, as well as to verify the need or not of this activation for therapeutic use. The PRP was obtained from four healthy crossbred geldings aged 13 to 16 years (15±1years), and was processed for observation and quantification of the platelet morphology by using the transmission electron microscopy. All PRP samples were activated with 10% calcium chloride (CaCl2) solution, pure bovine thrombin or associated with CaCl2. The control (pure PRP) was not pharmacologically activated. In the pure PRP samples, 49% of the platelets were classified as state of activation uncertain, 41% as resting, 9% as fully activated and 1% as irreversibly damaged. Treatment with 10% CaCl2 provided a distribution of 54% platelets in state of activation uncertain, 24% as fully activated, 20% as resting, and 2% as irreversibly damaged. The platelet morphology of the bovine thrombin treated samples did not fit into classification adopted, as showing irregular shape with emission of large filamentous pseudopods, appearance of ruptured and whole granules in the remaining cytoplasm and extracellular environment. There was effect of the treatment on the platelet morphology (P=0.03). The 10% CaCl2 is an adequate platelet-activating agent. However, in cases the use of PRP under its liquid form is necessary, the use of pure PRP is recommended, since besides presenting an adequate percentage of fully activated platelets it also has significant amount of the resting type, which can be activated by substances found in the injured tissue.

The effect of subconjunctival platelet-rich plasma on corneal epithelial wound healing

OBJECTIVE

Single-dose subconjunctival platelet-rich plasma (sPRP) injections with or without antibiotic treatment were investigated for their effect on corneal epithelial wound healing in a rabbit model.

MATERIALS AND METHODS

A total of 24 rabbits were used in this study. After collecting intracardiac blood samples from 16 rabbits, platelet-rich plasma was obtained by centrifugation. Animals were divided into 3 groups. A mechanical corneal epithelial defect of 7-mm diameter was created on the central cornea of the right eye of each animal. Group 1 (n = 8) received only sPRP, whereas group 2 (n = 8) received sPRP with topical antibiotic throughout the study. The third group (n = 8) served as the control group. Each animal was examined daily under biomicroscope for 10 days. Epithelial defect was measured in horizontal and vertical diameter with a 1/100 sensitive micrometer, and area of the defect was calculated. One animal was sacrificed in each group on the third and seventh day, and all remaining animals were sacrificed on the 10th day. Corneal histopathology was investigated for epithelial regeneration, presence of inflammation, and structural integrity of fibroblasts. All data were statistically analyzed for difference between the study groups.

RESULTS

Group 1 had a significantly smaller size in horizontal and vertical defect diameters on each day as compared with the control group. Healing of the epithelial defect in group 1 was found to be significantly different than that in the control group (P < 0.05). No significant difference was observed between group 2 and control group except for the first day. Group 1 had a significantly better healing process after the fourth day as compared with group 2. Histopathological investigations revealed a steady fibroblast migration, quicker epithelial regeneration, and less inflammation in group 1 as compared with the other 2 groups.

DISCUSSION AND CONCLUSIONS

sPRP seems to improve corneal epithelial wound healing. However, antibiotic and sPRP combination may have a retarded healing effect as compared with platelet-rich plasma alone.

Successful control of massive gastrointestinal bleeding following umbilical cord blood transplantation (UCBT) by use of recombinant activated factor VII (rFVIIa) and octreotide infusion

Post hematopoietic stem cell transplantation (HSCT) gastrointestinal (GI) bleeding is a dreaded complication. There are only five other reports (one randomised trial and four case reports) of use of rFVIIa for massive lower GI bleeding post-allogeneic HSCT. In only one publication, two adult patients showed complete response. Eroglu has reported a response rate of 50% to octreotide in gastrointestinal bleeding in patients without portal hypertension. We present a 10 month-old female child, who had three episodes of life threatening lower GI bleeding post unrelated Umbilical Stem Cell Transplant (UCBT) controlled successfully each time by use of rFVIIa and octreotide infusion and review of literature. To our knowledge this is the first and youngest case reported, in which both rFVIIa and octreotide have been used successfully to control life threatening lower GI bleeding post UCBT.

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.

Failure of recombinant factor VIIa in a patient with severe polymicrobial sepsis and postoperative uncontrolled intraabdominal bleeding

Background

This report discusses a case of unsuccessful treatment with recombinant factor VIIa (rFVIIa) in off-label use. The need for international guidelines concerning the off-label use of rFVIIa is outlined as well as the need for methods to control the efficacy of rFVIIa objectively.

Case presentation

54 year old male with severe polymicrobial sepsis due to a perforated diverticulitis of the sigmoid colon and consecutive overt disseminated intravascular coagulation. He suffered severe intraabdominal bleeding after abdominal surgery despite conventional haemostatic support. Repeated applications of factor VIIa temporarily improved coagulation essays but did not stop clinical bleeding. The patient died in multiorgan failure due to septic and haemorrhagic shock.

Conclusion

Off-label use of rFVIIa could result in more side effects than could be expected from literature because of a publication bias. However for most off-label applications large prospective, randomised and controlled trials to confirm the positive findings are missing. For the future, not only guidelines concerning the off-label use of rFVIIa are urgently needed but also guidelines for monitoring the efficacy of rFVIIa.

The potential role of recombinant activated FVII in the management of critical hemato-oncological bleeding: a systematic review

Recombinant activated factor VII (rFVIIa) is an hemostatic agent that was originally developed for the treatment of hemorrhage in patients with hemophilia and inhibitors. However, in the last few years rFVIIa has been employed with success in a broad spectrum of congenital and acquired bleeding conditions. In this systematic review we present the current knowledge on the use of this drug in patients suffering from hemato-oncological disorders, which are quite commonly complicated by severe hemorrhage. On the whole, data in the literature suggest a potential role for rFVIIa in the management of bleeding unresponsive to standard therapy in patients with hematological malignancies, including those undergoing bone marrow transplant. However, the vast majority of the currently available data are derived from uncontrolled studies including single cases or small series of patients. Thus, further trials with larger numbers of patients are needed to establish the most appropriate doses and timing of rFVIIa and to assess its efficacy and safety in this setting.

Activity and regulation of factor VIIa analogs with increased potency at the endothelial cell surface

BACKGROUND

Variants of recombinant factor VIIa (rFVIIa) with increased intrinsic activity have been developed to improve efficacy in the treatment of bleeding disorders in the future. The increased potency of FVIIa variants was demonstrated in limited in vitro and in vivo studies. However, further characterization of FVIIa variants is needed to evaluate their potential clinical use.

METHODS

In the present study, we investigated the interactions of two FVIIa variants, FVIIa(Q) and FVIIa(DVQ), with plasma inhibitors, tissue factor pathway inhibitor (TFPI) and antithrombin (AT), and vascular endothelium. TF-FVIIa activity or its inhibition was measured directly in an amidolytic activity assay or for its ability to activate factor X.

RESULTS

Both TFPI and AT/heparin inhibited the FVIIa variants more rapidly than the wild-type (WT) FVIIa in the absence of tissue factor (TF). In the presence of TF, TFPI, TFPI-Xa, and AT/heparin inhibited FVIIa and FVIIa variants at similar rates. Although the WT FVIIa failed to generate significant amounts of FXa on unperturbed endothelial cells, FVIIa variants, particularly FVIIa(DVQ), generated a substantial amount of FXa on unperturbed endothelium. Annexin V fully attenuated the FVIIa-mediated activation of FX on unperturbed endothelial cells. On stimulated human umbilical vein endothelial cells, FVIIa and FVIIa variants activated FX at similar rates, and annexin V blocked the activation only partly. AT/heparin and TFPI-Xa inhibited the activity of FVIIa and FVIIa variants bound to endothelial cell TF in a similar fashion. Interestingly, despite significant differences observed in FXa generation on unperturbed endothelium exposed to FVIIa and FVIIa analogs, no differences were found in thrombin generation when cells were exposed to FVIIa or FVIIa analogs under plasma mimicking conditions.

CONCLUSION

Overall, the present data suggest that although FVIIa variants generate substantial amounts of FXa, they do not generate excessive thrombin on the surface of endothelium.

Challenges in the Therapeutic Use of a “So-Called” Universal Hemostatic Agent: Recombinant Factor VIIa

Recombinant factor VIIa (rFVIIa) was developed in the early 1990s to provide “bypassing” hemostatic therapy for hemophilia A and B patients with inhibitors. More recently, it has been licensed for use in patients with inherited deficiency of factor VII. Since it was licensed for use in hemophilia with inhibitors in the US, Europe, and other countries for these specific indications, it has been used selectively but in a wide array of clinical settings for uncontrolled hemorrhage in individuals without an inherited bleeding disorder. Many of these uses have been described in the medical literature as case reports or small, uncontrolled series. Several randomized clinical trials (RCT) for these “off-label” medical uses have been published in recent months and will serve as the focus of this review. In particular, a review of an RCT for spontaneous intracranial hemorrhage that has demonstrated clinical efficacy in reducing both mortality and volume of central nervous system hemorrhage will be offered. A brief discussion of hypothesized physiologic mechanisms of supraphysiologic doses of rFVIIa will introduce the clinical discussion of these broad off-label uses. Since rFVIIa is a very expensive therapy, possible strategies for optimizing its use in the these settings will be presented.