998 q 2001 Blackwell Science Ltd

SHORT REPORT

Beriplex P/N reverses severe warfarin-induced

overanticoagulation immediately and completely in patients

presenting with major bleeding

Gillian Evans, Roger Luddington and Trevor Baglin Department of Haematology, Addenbrooke's Hospital,

Cambridge University Hospitals NHS Trust, Cambridge, UK

Received 25 May 2001, accepted for publication 8 August 2001

Summary. In an open non-randomized study, 10 patientswith major bleeding and an Internationalized Normal Ratio(INR) greater than 14 were treated with 5 mg ofintravenous vitamin K and 30 iu/kg of a single concentratecontaining factors II, VII, IX and X (Beriplex P/N; AventisBehring). The levels of these factors before and immediatelyafter treatment were 4´7, 1´6, 8´5 and 1´1 iu/dl and 94, 30,66 and 91 iu/dl respectively. The median INR before

treatment was greater than 20 and, after treatment, 1´1.All patients had a satisfactory clinical response withimmediate cessation of bleeding, and no thromboemboliccomplications occurred.

Keywords: warfarin, anticoagulation, overanticoagulation,Beriplex P/ N, prothrombin complex.

Treatment with coumarin oral anticoagulants, such aswarfarin, is effective antithrombotic therapy, but patientstreated with these drugs are at significant risk of bleeding.Oral anticoagulants are increasingly prescribed for bothprevention and treatment of thromboembolic disease and,by 1996, approximately 1 in 200 of the UK population werebeing treated with warfarin. The annual risk of bleeding isapproximately 15% with two or three major bleeds per 100patient±years (van der Meer et al, 1993; Cannegieter et al,1995; Palareti et al, 1996). Although major bleeding canoccur at therapeutic levels, the risk of bleeding rises withincreasing intensity of anticoagulation (van der Meer et al,1993; Cannegieter et al, 1995; Palareti et al, 1996). TheInternational Normalized Ratio (INR) is recommended forlaboratory monitoring of oral anticoagulant therapy and asa guide to warfarin dose adjustment (British Committee forStandards in Haematology, 1998). The risk of bleeding as aresult of oral anticoagulation increases exponentially as theINR rises above 5´0 (Landefield & Beyth, 1993; Cannegieteret al, 1995; Palareti et al, 1996). Overanticoagulatedpatients with major life-threatening bleeding, or whorequire emergency surgery, need immediate effective rever-sal of anticoagulation. The options for reversal include theadministration of vitamin K, fresh frozen plasma (FFP) andcoagulation factor concentrates (Baglin, 1998). The

response to vitamin K is slow and unpredictable. Freshfrozen plasma given at the recommended dosage of 15 ml/kgdoes not completely reverse the anticoagulant effect, andthe calculated volumes required for complete reversal areprohibitive (Makris et al, 1996). Limited studies haveevaluated the role of coagulation factor concentratescontaining factors II, VII, IX and X (Taberner et al, 1976;Makris et al, 1996; Nitu et al, 1998). In the study by Makriset al (1996), most patients treated with prothrombincomplex concentrates were only moderately overanticoagu-lated with a median INR of 5´8. In an audit report (Nitu et al,1998), the severity of overanticoagulation was unknown.The aim of this study was to determine the efficacy andsafety of a single prothrombin complex concentrate contain-ing factors II, VII, IX and X (Beriplex P/N; Aventis Behring)in patients presenting with an INR greater than 8´0 withmajor haemorrhage or requiring urgent surgery. Primaryoutcome variables were clinical response, levels of coagula-tion factors and INR. Safety variables were blood loss andthromboembolic complications. In addition, for the firsttime, the endogenous thrombin potential (ETP) wasmeasured to study thrombin generation in these patientsbefore and after treatment.

PATIENTS AND METHODS

Patients. The study was an open non-randomized cohortstudy. Primary outcome variables were clinical response,

British Journal of Haematology, 2001, 115, 998±1001

Correspondence: Dr Trevor Baglin, Department of Haematology,Addenbrooke's Hospital, Cambridge University Hospitals NHS Trust,

Cambridge CB2 2QQ, UK. E-mail: tpb20@cam.ac.uk

levels of coagulation factors and INR. The study wasapproved by the Local Research Ethics Committee, andwritten informed consent was obtained from all patients orfrom relatives when the patient was unable to give informedconsent. Inclusion criteria were INR greater than 8´0, theneed for urgent reversal of overanticoagulation and age over18 years. Exclusion criteria were pregnancy, breastfeedingand any history of hypersensitivity to coagulation factorconcentrates.

Treatment. Patients were treated with 30 units/kg Ber-iplex P/N given as a slow intravenous injection over 10±15 min. Beriplex P/N is a coagulation factor concentratecontaining 120±280 mg of protein per vial. Vitamin K-dependent coagulation factor content was assayed withreference to World Health Organization (WHO) standards.Each vial contained factor IX 400±620 iu (WHO standard96/854), factor II 400±960 iu (WHO standard 84/683),factor VII 200±500 iu (WHO standard 94/746), factor X440±1200 iu (WHO standard 84/683) and protein C 300±900 iu (WHO standard 86/622). In addition, each vialcontained 4±30 iu of antithrombin, 8±40 iu of heparin and40±80 mg of albumin. In addition, all patients received5 mg of vitamin K intravenously.

Investigation schedule. Clinical and laboratory variableswere evaluated before treatment and 30 min, 6±8 h, 24 hand 48 h after treatment. In addition to the primaryoutcome variables, blood counts and alanine transaminase(ALT) were measured at each time point. A clinicalexamination was performed at each time point. Patientswere also examined specifically for clinical signs of deep-veinthrombosis or pulmonary embolus until discharge fromhospital.

Laboratory methods. Venous blood was collected in0´106 mol/l trisodium citrate (Monovette Sarstedt, Leice-ster, UK). Platelet-poor plasma (PPP) was produced bycentrifugation at 2500 g for 15 min. Aliquots were thenfrozen at 2808C until assay.

Prothrombin times and factor assays were measured onthe MDA180 coagulation analyser (Organon Teknika,Durham, NC, USA). Simplastin Excel S (Organon Teknika)was used for the measurement of prothrombin times withcalculation of INRs by reagent lot-specific InternationalSensitivity Index (ISI) and a locally derived geometric meannormal prothrombin time. Factors II, VII and X wereassayed by a one-stage prothrombin time-based assay withSimplastin Excel S and specific factor-deficient substrateplasmas (Organon Teknika). Factor IX was assayed by a one-stage activated partial thromboplastin time-based assaywith Platelin LS and factor IX-deficient substrate plasmas(Organon Teknika).

The ETP was measured by the method described byHemker et al (1986). Essentially, thrombin generation wasinitiated in a defibrinated plasma sample by the addition of adilute thromboplastin reagent (Simplastin HTF; OrganonTeknika). Subsamples of the reaction mixture were trans-ferred to a thrombin-specific chromogenic substrate (Sub-strate TH-1; Baxter, Vienna, Austria). The endogenousthrombin potential was calculated from the area under thethrombin generation curve. The normal range for the

thrombin potential was determined from 12 healthy adultsnot taking anticoagulant drugs or any other medication.

RESULTS

PatientsTen patients (eight female) were entered into the study.Median age was 73 years, range 39±88 years. Six out of 10patients had an INR greater than 20´0; the remaining fourhad INRs of 8´9, 14´4, 15´8 and 18´0. Bleeding complica-tions were malaena (three), haematuria (two), haematemesis(one), haemoptysis (one), epistaxis (one), retroperitonealbleeding (one) and pulmonary haemorrhage (one).

Clinical response and safety variablesThere were no deaths. All patients had a satisfactory clinicalresponse to Beriplex P/N with cessation of bleeding in everypatient by the 6±8 h assessment. In practice, oncetreatment was given, there was no evidence of freshbleeding. No thromboembolic complications occurred, andthere were no other adverse events.

Two patients developed thrombocytopenia. On admission,platelet counts were 145 and 151 � 109/l and, aftertreatment, these fell to 81 and 110 � 109/l respectively.

Two patients had abnormal ALT levels on admission. Onepatient was subsequently found to have a rectal carcinomawith liver metastases.

Laboratory variablesThe INR, levels of factors II, VII, IX and X and ETPs areshown in Table I. All INRs measured 30 min after treat-ment were less than 1´3. At 30 min, two patients had factorVII levels less than 25 iu/dl (24´4 and 15´4 iu/dlrespectively). All factor II, IX and X levels were greaterthan 50 iu/dl. By 48 h, factor levels were beginning to fallslightly, and five patients had an INR of 1´6 and one an INRof 1´7, indicating that 5 mg of intravenous vitamin K willnot maintain complete correction of overanticoagulation inseverely overanticoagulated patients.

Endogenous thrombin potentialsAt presentation, the ETP was less than 1 nmol/min in ninepatients and only 1 nmol/min in the tenth (normal 124±208 nmol/min). By 30 min, the ETP was completelynormalized. By 24 h, the ETP was falling again, indicatingthat 5 mg of intravenous vitamin K will not maintaincomplete correction of overanticoagulation in this popula-tion of patients.

DISCUSSION

Until recently, FFP has been the treatment choice for theemergency reversal of overanticoagulation resulting fromwarfarin and related oral anticoagulant drugs. Despite thispractice, there was until recently little, if any, data on itsefficacy in normalizing vitamin K-dependent coagulationfactor levels in this situation. Makris et al (1996) showedunequivocally, in a study in Sheffield, that 800 ml of FFP didnot reverse warfarin-induced coagulopathy. Of 12 patients

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Short Report 999

who received FFP, the mean INR before treatment was 10´2,and this was reduced to a mean of 2´3 15 min aftertreatment. Furthermore, the median factor IX level aftertreatment was only 19 iu/dl. This is inadequate for normalhaemostasis. In the same study, 29 patients were treatedwith concentrates containing factors II, VII, IX and X atdoses of 25±50 iu/kg. The mean pretreatment INR was 5´8,and this was reduced to a mean INR of 1´3 after treatment.The median levels of factors II, VII, IX and X in 14 patientsfor whom there was detailed information were 50, 74, 68´5and 72 iu/dl after treatment with factor concentrates. Thestudy was particularly important, as it indicated that therelative changes in levels of coagulation factors in responseto treatment with FFP and concentrates were clinicallyrelevant. It also highlighted the fact that the INR is notaffected by the factor IX level, which was particularly lowafter treatment with FFP. Despite the importance of thisstudy, the patients treated with concentrate were onlymoderately overanticoagulated and, until now, it wasunknown what dose of concentrate would be required toreverse severe overanticoagulation and whether this treat-ment would result in a clinical response. In an audit of 20patients treated, at the Royal Free Hospital in London, witha combination of a factor VII concentrate and a concentrateof factors II, IX and X given in doses ranging from 12 to 50iu/kg, complete reversal did not occur in every patient (Nituet al, 1998). The degree of overanticoagulation in thesepatients was unknown, as INRs were only measured up to6´0. In the present study, we have now shown that BeriplexP/N, which is a single concentrate containing all fourfactors II, VII, IX and X, given at a dose of 30 iu/kg based onfactor IX content will completely and immediately reversesevere overanticoagulation in patients presenting withbleeding. In our study, every patient had an INR greaterthan 14´0 and, in more than half, the INR was greater than20. Despite this severity of overanticoagulation, 30 minafter treatment with Beriplex P/N, the median INR was 1´1(maximum 1´3), and median levels of II, VII, IX and X were94, 30, 66 and 91 iu/dl. In patients with congenital factorVII deficiency, a level of only 10±15 iu/dl is considered to beadequate for haemostasis (Roberts & Eberst, 1994). Incontrast, higher levels of factors II and IX are required forhaemostasis. In our study, post-treatment levels of II and IX

were greater than 50 iu/dl and remained above this level,except in one patient who had a factor II level of 44 iu/dlafter 48 h.

There has been concern regarding the use of prothrombincomplex concentrates in patients with a thrombotictendency after reports of thrombosis and disseminatedintravascular coagulation (DIC) in patients with haemophi-lia B treated with these products. However, these episodestypically occurred in the setting of surgery or liver disease,which are associated with a particularly high risk ofthrombosis, or after frequently repeated treatments. Inthese patients with congenital haemophilia B, repeatedtreatment may result in a cumulative risk of thrombosis.Our study and the previous two studies (Makris et al, 1996;Nitu et al, 1998) include 59 patients. There were nothromboembolic events in any of the studies. Based on 0/59,the upper 95% confidence limit for thromboemboliccomplications is 6%, or 1 in 16. It may of course beconsiderably lower, and possibly close to zero. However, evena risk of 1 in 16 will be considerably lower than the risk ofdeath in patients presenting with intracranial haemorrhageor major gastrointestinal or retroperitoneal bleeding. Thisfigure now permits a degree of benefit:risk analysis whendeciding how to treat patients presenting with bleeding inassociation with a high INR.

This study is the only one in which the ETP has beenmeasured. The ETP reflects hypercoagulability in patientswith heritable thrombophilia (Wielders et al, 1997) andhypocoagulability in patients receiving oral anticoagulanttherapy (Hemker & Beguin, 2000). It has been proposedthat an increase in the ETP to more than 110% of normalindicates a thrombotic tendency, whereas a level between20% and 40% indicates effective anticoagulation (Hemker &Beguin, 2000). In this study, severely overanticoagulatedpatients had an ETP less than 1% of the lower limit of ournormal range. Immediately after treatment, the ETP wasgreater than 50% of the lower limit of normal in everypatient. The ETP exceeded the upper limit of normal by 10%in only one patient. To our knowledge, the ETP has not beenused previously to assess hypercoagulability after reversal ofanticoagulation with prothrombin complex concentrates.Given the ability of the ETP to detect hypercoagulability inpatients with heritable thrombophilia (Wielders et al, 1997),

Table I. Median and range of laboratory variables at each study time point.

Study time points

Pretreatment 30 min 6±8 h 24 h 48 h

INR (, 1´3) . 20 (15´8±. 20) 1´1 (1´0±1´3) 1´1 (1´0±1´4) 1´1 (1´0±1´4) 1´6 (1´0±1´7)

II (. 50) 4´7 (0´8±7´9) 94 (64±112) 79 (56±123) 80 (53±152) 67 (44±126)VII (. 50) 1´6 (0´3±3´0) 30 (15±57) 51 (32±84) 82 (63±126) 45 (37±112)

IX (. 50) 8´5 (4±12) 66 (52±91) 84 (70±176) 119 (78±191) 110 (75±167)

X (. 50) 1´1 (0´5±3´0) 91 (73±126) 80 (59±128) 83 (51±105) 54 (34±96)

ETP (120±208) 0 (0±1) 151 (56±247) 119 (104±229) 90 (22±226) 71 (3±228)

Normal values are indicated in brackets in column 1. Factor levels in iu/dl, ETP in nmol/min.

1000 Short Report

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our results suggest that treatment with Beriplex P/N is notassociated with the development of a significant hypercoa-gulable state.

By 48 h, the INR was significantly elevated again, albeitto a maximum of 1´7, and factor levels were beginning tofall. This is an important observation and indicates that, inthis group of severely overanticoagulated patients, a singledose of 5 mg of intravenous vitamin K will not maintaincomplete reversal beyond 24 h. It is therefore necessary toevaluate the continuing bleeding and thrombotic risk anddecide whether complete reversal should be maintained, inwhich case repeated doses of vitamin K should be given, orwhether a mild hypocoagulable state should be permitted. Itis clear that the INR must be monitored at least daily.

In conclusion, this study indicates that overanticoagula-tion can be completely and immediately reversed by oneinjection of a single concentrate of all four vitamin K-dependent clotting factors. Based on the absence ofthromboembolic complications in this and previouslyreported studies, an analysis of benefit and risk can nowbe made for individual patients depending on the degree ofoveranticoagulation and the severity of bleeding. The studyalso indicates clearly that vitamin K should also be given inan appropriate dosing schedule to maintain complete orpartial reversal, depending on the need for anticoagulation,with regular monitoring of the INR.

ACKNOWLEDGMENTS

We are grateful to Helen Yarranton, Maher Ghandi,Sabapathy Paneerselvam and Emma Morris for recruitingpatients into the study.

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