Non-clotting factor therapies for preventing bleeds in people with congenital hemophilia A or B

BACKGROUND

Management of congenital hemophilia A and B is by prophylactic or on-demand replacement therapy with clotting factor concentrates. The effects of newer non-clotting factor therapies such as emicizumab, concizumab, marstacimab, and fitusiran compared with existing standards of care are yet to be systematically reviewed.

OBJECTIVES

To assess the effects (clinical, economic, patient-reported, and adverse outcomes) of non-clotting factor therapies for preventing bleeding and bleeding-related complications in people with congenital hemophilia A or B compared with prophylaxis with clotting factor therapies, bypassing agents, placebo, or no prophylaxis.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group's Coagulopathies Trials Register, electronic databases, conference proceedings, and reference lists of relevant articles and reviews. The date of the last search was 16 August 2023.

SELECTION CRITERIA

Randomized controlled trials (RCTs) evaluating people with congenital hemophilia A or B with and without inhibitors, who were treated with non-clotting factor therapies to prevent bleeds.

DATA COLLECTION AND ANALYSIS

Two review authors independently reviewed studies for eligibility, assessed risk of bias, and extracted data for the primary outcomes (bleeding rates, health-related quality of life (HRQoL), adverse events) and secondary outcomes (joint health, pain scores, and economic outcomes). We assessed the mean difference (MD), risk ratio (RR), 95% confidence interval (CI) of effect estimates, and evaluated the certainty of the evidence using GRADE.

MAIN RESULTS

Six RCTs (including 397 males aged 12 to 75 years) were eligible for inclusion. Prophylaxis versus on-demand therapy in people with inhibitors Four trials (189 participants) compared emicizumab, fitusiran, and concizumab with on-demand therapy in people with inhibitors. Prophylaxis using emicizumab likely reduced annualized bleeding rates (ABR) for all bleeds (MD -22.80, 95% CI -37.39 to -8.21), treated bleeds (MD -20.40, 95% CI -35.19 to -5.61), and annualized spontaneous bleeds (MD -15.50, 95% CI -24.06 to -6.94), but did not significantly reduce annualized joint and target joint bleeding rates (AjBR and AtjBR) (1 trial; 53 participants; moderate-certainty evidence). Fitusiran also likely reduced ABR for all bleeds (MD -28.80, 95% CI -40.07 to -17.53), treated bleeds (MD -16.80, 95% CI -25.80 to -7.80), joint bleeds (MD -12.50, 95% CI -19.91 to -5.09), and spontaneous bleeds (MD -14.80, 95% CI -24.90 to -4.71; 1 trial; 57 participants; moderate-certainty evidence). No evidence was available on the effect of bleed prophylaxis using fitusiran versus on-demand therapy on AtjBR. Concizumab may reduce ABR for all bleeds (MD -12.31, 95% CI -19.17 to -5.45), treated bleeds (MD -10.10, 95% CI -17.74 to -2.46), joint bleeds (MD -9.55, 95% CI -13.55 to -5.55), and spontaneous bleeds (MD -11.96, 95% CI -19.89 to -4.03; 2 trials; 78 participants; very low-certainty evidence), but not target joint bleeds (MD -1.00, 95% CI -3.26 to 1.26). Emicizumab prophylaxis resulted in an 11.31-fold increase, fitusiran in a 12.5-fold increase, and concizumab in a 1.59-fold increase in the proportion of participants with no bleeds. HRQoL measured using the Haemophilia Quality of Life Questionnaire for Adults (Haem-A-QoL) physical and total health scores was improved with emicizumab, fitusiran, and concizumab prophylaxis (low-certainty evidence). Non-serious adverse events were higher with non-clotting factor therapies versus on-demand therapy, with injection site reactions being the most frequently reported adverse events. Transient antidrug antibodies were reported for fitusiran and concizumab. Prophylaxis versus on-demand therapy in people without inhibitors Two trials (208 participants) compared emicizumab and fitusiran with on-demand therapy in people without inhibitors. One trial assessed two doses of emicizumab (1.5 mg/kg weekly and 3.0 mg/kg bi-weekly). Fitusiran 80 mg monthly, emicizumab 1.5 mg/kg/week, and emicizumab 3.0 mg/kg bi-weekly all likely resulted in a large reduction in ABR for all bleeds, all treated bleeds, and joint bleeds. AtjBR was not reduced with either of the emicizumab dosing regimens. The effect of fitusiran prophylaxis on target joint bleeds was not assessed. Spontaneous bleeds were likely reduced with fitusiran (MD -20.21, 95% CI -32.12 to -8.30) and emicizumab 3.0 mg/kg bi-weekly (MD -15.30, 95% CI -30.46 to -0.14), but not with emicizumab 1.5 mg/kg/week (MD -14.60, 95% CI -29.78 to 0.58). The percentage of participants with zero bleeds was higher following emicizumab 1.5 mg/kg/week (50% versus 0%), emicizumab 3.0 mg/kg bi-weekly (40% versus 0%), and fitusiran prophylaxis (40% versus 5%) compared with on-demand therapy. Emicizumab 1.5 mg/kg/week did not improve Haem-A-QoL physical and total health scores, EQ-5D-5L VAS, or utility index scores (low-certainty evidence) when compared with on-demand therapy at 25 weeks. Emicizumab 3.0 mg/kg bi-weekly may improve HRQoL measured by the Haem-A-QoL physical health score (MD -15.97, 95% CI -29.14 to -2.80) and EQ-5D-5L VAS (MD 9.15, 95% CI 2.05 to 16.25; 1 trial; 43 participants; low-certainty evidence). Fitusiran may result in improved HRQoL shown as a reduction in Haem-A-QoL total score (MD -7.06, 95% CI -11.50 to -2.62) and physical health score (MD -19.75, 95% CI -25.76 to -11.94; 1 trial; 103 participants; low-certainty evidence). The risk of serious adverse events in participants without inhibitors also likely did not differ following prophylaxis with either emicizumab or fitusiran versus on-demand therapy (moderate-certainty evidence). Transient antidrug antibodies were reported in 4% (3/80) participants to fitusiran, with no observed effect on antithrombin lowering. A comparison of the different dosing regimens of emicizumab identified no differences in bleeding, safety, or patient-reported outcomes. No case of treatment-related cancer or mortality was reported in any study group. None of the included studies assessed our secondary outcomes of joint health, clinical joint function, and economic outcomes. None of the included studies evaluated marstacimab.

AUTHORS' CONCLUSIONS

Evidence from RCTs shows that prophylaxis using non-clotting factor therapies compared with on-demand treatment may reduce bleeding events, increase the percentage of individuals with zero bleeds, increase the incidence of non-serious adverse events, and improve HRQoL. Comparative assessments with other prophylaxis regimens, assessment of long-term joint outcomes, and assessment of economic outcomes will improve evidence-based decision-making for the use of these therapies in bleed prevention.

Pharmacological interventions for the prevention of bleeding in people undergoing definitive fixation or joint replacement for hip, pelvic and long bone fractures

BACKGROUND

Pelvic, hip, and long bone fractures can result in significant bleeding at the time of injury, with further blood loss if they are treated with surgical fixation. People undergoing surgery are therefore at risk of requiring a blood transfusion and may be at risk of peri-operative anaemia. Pharmacological interventions for blood conservation may reduce the risk of requiring an allogeneic blood transfusion and associated complications.

OBJECTIVES

To assess the effectiveness of different pharmacological interventions for reducing blood loss in definitive surgical fixation of the hip, pelvic, and long bones.

SEARCH METHODS

We used a predefined search strategy to search CENTRAL, MEDLINE, PubMed, Embase, CINAHL, Transfusion Evidence Library, ClinicalTrials.gov, and the WHO International Clinical Trials Registry Platform (ICTRP) from inception to 7 April 2022, without restrictions on language, year, or publication status. We handsearched reference lists of included trials to identify further relevant trials. We contacted authors of ongoing trials to acquire any unpublished data.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) of people who underwent trauma (non-elective) surgery for definitive fixation of hip, pelvic, and long bone (pelvis, tibia, femur, humerus, radius, ulna and clavicle) fractures only. There were no restrictions on gender, ethnicity, or age. We excluded planned (elective) procedures (e.g. scheduled total hip arthroplasty), and studies published since 2010 that had not been prospectively registered. Eligible interventions included: antifibrinolytics (tranexamic acid, aprotinin, epsilon-aminocaproic acid), desmopressin, factor VIIa and XIII, fibrinogen, fibrin sealants, and non-fibrin sealants.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial eligibility and risk of bias, and extracted data. We assessed the certainty of the evidence using GRADE. We did not perform a network meta-analysis due to lack of data.

MAIN RESULTS

We included 13 RCTs (929 participants), published between 2005 and 2021. Three trials did not report any of our predefined outcomes and so were not included in quantitative analyses (all were tranexamic acid versus placebo). We identified three comparisons of interest: intravenous tranexamic acid versus placebo; topical tranexamic acid versus placebo; and recombinant factor VIIa versus placebo. We rated the certainty of evidence as very low to low across all outcomes. Comparison 1. Intravenous tranexamic acid versus placebo Intravenous tranexamic acid compared to placebo may reduce the risk of requiring an allogeneic blood transfusion up to 30 days (RR 0.48, 95% CI 0.34 to 0.69; 6 RCTs, 457 participants; low-certainty evidence) and may result in little to no difference in all-cause mortality (Peto odds ratio (Peto OR) 0.38, 95% CI 0.05 to 2.77; 2 RCTs, 147 participants; low-certainty evidence).  It may result in little to no difference in risk of participants experiencing myocardial infarction (risk difference (RD) 0.00, 95% CI -0.03 to 0.03; 2 RCTs, 199 participants; low-certainty evidence), and cerebrovascular accident/stroke (RD 0.00, 95% CI -0.02 to 0.02; 3 RCTs, 324 participants; low-certainty evidence).  We are uncertain if there is a difference between groups for risk of deep vein thrombosis (Peto OR 2.15, 95% CI 0.22 to 21.35; 4 RCTs, 329 participants, very low-certainty evidence), pulmonary embolism (Peto OR 1.08, 95% CI 0.07 to 17.66; 4 RCTs, 329 participants; very low-certainty evidence), and suspected serious drug reactions (RD 0.00, 95% CI -0.03 to 0.03; 2 RCTs, 185 participants; very low-certainty evidence). No data were available for number of red blood cell units transfused, reoperation, or acute transfusion reaction. We downgraded the certainty of the evidence for imprecision (wide confidence intervals around the estimate and small sample size, particularly for rare events), and risk of bias (unclear or high risk methods of blinding and allocation concealment in the assessment of subjective measures), and upgraded the evidence for transfusion requirement for a large effect.  Comparison 2. Topical tranexamic acid versus placebo We are uncertain if there is a difference between topical tranexamic acid and placebo for risk of requiring an allogeneic blood transfusion (RR 0.31, 95% CI 0.08 to 1.22; 2 RCTs, 101 participants), all-cause mortality (RD 0.00, 95% CI -0.10 to 0.10; 1 RCT, 36 participants), risk of participants experiencing myocardial infarction (Peto OR 0.15, 95% CI 0.00 to 7.62; 1 RCT, 36 participants), cerebrovascular accident/stroke (RD 0.00, 95% CI -0.06 to 0.06; 1 RCT, 65 participants); and deep vein thrombosis (Peto OR 1.11, 95% CI 0.07 to 17.77; 2 RCTs, 101 participants).  All outcomes reported were very low-certainty evidence. No data were available for number of red blood cell units transfused, reoperation, incidence of pulmonary embolism, acute transfusion reaction, or suspected serious drug reactions. We downgraded the certainty of the evidence for imprecision (wide confidence intervals around the estimate and small sample size, particularly for rare events), inconsistency (moderate heterogeneity), and risk of bias (unclear or high risk methods of blinding and allocation concealment in the assessment of subjective measures, and high risk of attrition and reporting biases in one trial). Comparison 3. Recombinant factor VIIa versus placebo   Only one RCT of 48 participants reported data for recombinant factor VIIa versus placebo, so we have not presented the results here.

AUTHORS' CONCLUSIONS

We cannot draw conclusions from the current evidence due to lack of data. Most published studies included in our analyses assessed the use of tranexamic acid (compared to placebo, or using different routes of administration).  We identified 27 prospectively registered ongoing RCTs (total target recruitment of 4177 participants by end of 2023). The ongoing trials create six new comparisons: tranexamic acid (tablet + injection) versus placebo; intravenous tranexamic acid versus oral tranexamic acid; topical tranexamic acid versus oral tranexamic acid; different intravenous tranexamic acid dosing regimes; topical tranexamic acid versus topical fibrin glue; and fibrinogen (injection) versus placebo.

Postoperative Bleeding Following Preoperative Clopidogrel Administration in Patients with Haemoglobin Level Above 110 g/L Undergoing Urgent CABG

INTRODUCTION

Patients with acute coronary syndrome usually receive dual antiplatelet therapy (DAPT) (usually clopidogrel + aspirin) prior to coronary catheterization, and approximately 10% of these patients require coronary artery bypass grafting (CABG). DAPT has favorable effects on prevention of thrombus formation, but it can have deleterious effects on surgical hemostasis. Anaemia, if present, gives additional risk to such patients. The aim of this study was to examine if DAPT affects postoperative bleeding in patients with haemoglobin levels above 110 g/L, who underwent urgent or emergent CABG, less than five days after stopping DAPT therapy.

METHODS

Data were collected prospectively on 122 CABG patients, operated by a surgical team from March 2008 to August 2013. Patients were stratified into two groups: group 1 received DAPT within 5 days of CABG (n=65), and group 2 where DAPT was discontinued for more than 5 days prior to CABG (n=57). All patients were diagnosed with acute coronary syndrome preoperatively, and all of them had haemoglobin levels above 110 g/L. Patients who needed reoperation, combined procedures, or off-pump revascularization were excluded.

RESULTS

There was no hospital mortality. Mean chest tube losses after the surgical revascularization did not differ significantly, but group 1 received a higher quantity of transfused red blood cells and platelets.

CONCLUSION

Urgent and emergent surgical revascularization using extracorporeal circulation in patients with acute coronary syndrome whose preoperative haemoglobin levels are above 110 g/L is a safe and effective procedure. We suggest that, where indicative, one may perform CABG in less than 5 days after the clopidogrel discontinuation.

Pathogen-reduced platelets for the prevention of bleeding

BACKGROUND

Platelet transfusions are used to prevent and treat bleeding in people who are thrombocytopenic. Despite improvements in donor screening and laboratory testing, a small risk of viral, bacterial, or protozoal contamination of platelets remains. There is also an ongoing risk from newly emerging blood transfusion-transmitted infections for which laboratory tests may not be available at the time of initial outbreak.One solution to reduce the risk of blood transfusion-transmitted infections from platelet transfusion is photochemical pathogen reduction, in which pathogens are either inactivated or significantly depleted in number, thereby reducing the chance of transmission. This process might offer additional benefits, including platelet shelf-life extension, and negate the requirement for gamma-irradiation of platelets. Although current pathogen-reduction technologies have been proven to reduce pathogen load in platelet concentrates, a number of published clinical studies have raised concerns about the effectiveness of pathogen-reduced platelets for post-transfusion platelet count recovery and the prevention of bleeding when compared with standard platelets.This is an update of a Cochrane review first published in 2013.

OBJECTIVES

To assess the effectiveness of pathogen-reduced platelets for the prevention of bleeding in people of any age requiring platelet transfusions.

SEARCH METHODS

We searched for randomised controlled trials (RCTs) in the Cochrane Central Register of Controlled Trials (CENTRAL) (the Cochrane Library 2016, Issue 9), MEDLINE (from 1946), Embase (from 1974), CINAHL (from 1937), the Transfusion Evidence Library (from 1950), and ongoing trial databases to 24 October 2016.

SELECTION CRITERIA

We included RCTs comparing the transfusion of pathogen-reduced platelets with standard platelets, or comparing different types of pathogen-reduced platelets.

DATA COLLECTION AND ANALYSIS

We used the standard methodological procedures expected by Cochrane.

MAIN RESULTS

We identified five new trials in this update of the review. A total of 15 trials were eligible for inclusion in this review, 12 completed trials (2075 participants) and three ongoing trials. Ten of the 12 completed trials were included in the original review. We did not identify any RCTs comparing the transfusion of one type of pathogen-reduced platelets with another.Nine trials compared Intercept® pathogen-reduced platelets to standard platelets, two trials compared Mirasol® pathogen-reduced platelets to standard platelets; and one trial compared both pathogen-reduced platelets types to standard platelets. Three RCTs were randomised cross-over trials, and nine were parallel-group trials. Of the 2075 participants enrolled in the trials, 1981 participants received at least one platelet transfusion (1662 participants in Intercept® platelet trials and 319 in Mirasol® platelet trials).One trial included children requiring cardiac surgery (16 participants) or adults requiring a liver transplant (28 participants). All of the other participants were thrombocytopenic individuals who had a haematological or oncological diagnosis. Eight trials included only adults.Four of the included studies were at low risk of bias in every domain, while the remaining eight included studies had some threats to validity.Overall, the quality of the evidence was low to high across different outcomes according to GRADE methodology.We are very uncertain as to whether pathogen-reduced platelets increase the risk of any bleeding (World Health Organization (WHO) Grade 1 to 4) (5 trials, 1085 participants; fixed-effect risk ratio (RR) 1.09, 95% confidence interval (CI) 1.02 to 1.15; I2 = 59%, random-effect RR 1.14, 95% CI 0.93 to 1.38; I2 = 59%; low-quality evidence).There was no evidence of a difference between pathogen-reduced platelets and standard platelets in the incidence of clinically significant bleeding complications (WHO Grade 2 or higher) (5 trials, 1392 participants; RR 1.10, 95% CI 0.97 to 1.25; I2 = 0%; moderate-quality evidence), and there is probably no difference in the risk of developing severe bleeding (WHO Grade 3 or higher) (6 trials, 1495 participants; RR 1.24, 95% CI 0.76 to 2.02; I2 = 32%; moderate-quality evidence).There is probably no difference between pathogen-reduced platelets and standard platelets in the incidence of all-cause mortality at 4 to 12 weeks (6 trials, 1509 participants; RR 0.81, 95% CI 0.50 to 1.29; I2 = 26%; moderate-quality evidence).There is probably no difference between pathogen-reduced platelets and standard platelets in the incidence of serious adverse events (7 trials, 1340 participants; RR 1.09, 95% CI 0.88 to 1.35; I2 = 0%; moderate-quality evidence). However, no bacterial transfusion-transmitted infections occurred in the six trials that reported this outcome.Participants who received pathogen-reduced platelet transfusions had an increased risk of developing platelet refractoriness (7 trials, 1525 participants; RR 2.94, 95% CI 2.08 to 4.16; I2 = 0%; high-quality evidence), though the definition of platelet refractoriness differed between trials.Participants who received pathogen-reduced platelet transfusions required more platelet transfusions (6 trials, 1509 participants; mean difference (MD) 1.23, 95% CI 0.86 to 1.61; I2 = 27%; high-quality evidence), and there was probably a shorter time interval between transfusions (6 trials, 1489 participants; MD -0.42, 95% CI -0.53 to -0.32; I2 = 29%; moderate-quality evidence). Participants who received pathogen-reduced platelet transfusions had a lower 24-hour corrected-count increment (7 trials, 1681 participants; MD -3.02, 95% CI -3.57 to -2.48; I2 = 15%; high-quality evidence).None of the studies reported quality of life.We did not evaluate any economic outcomes.There was evidence of subgroup differences in multiple transfusion trials between the two pathogen-reduced platelet technologies assessed in this review (Intercept® and Mirasol®) for all-cause mortality and the interval between platelet transfusions (favouring Intercept®).

AUTHORS' CONCLUSIONS

Findings from this review were based on 12 trials, and of the 1981 participants who received a platelet transfusion only 44 did not have a haematological or oncological diagnosis.In people with haematological or oncological disorders who are thrombocytopenic due to their disease or its treatment, we found high-quality evidence that pathogen-reduced platelet transfusions increase the risk of platelet refractoriness and the platelet transfusion requirement. We found moderate-quality evidence that pathogen-reduced platelet transfusions do not affect all-cause mortality, the risk of clinically significant or severe bleeding, or the risk of a serious adverse event. There was insufficient evidence for people with other diagnoses.All three ongoing trials are in adults (planned recruitment 1375 participants) with a haematological or oncological diagnosis.