Successful Long Term Therapeutic Expression of Factor VIII in Hemophilia A Dogs After Administration of AAV-cFVIII Using a Two-Chain or Single Chain Delivery Approach.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 546-546
Author(s):  
Denise E. Sabatino ◽  
Ekaterina Altynova ◽  
Amy M. Lange ◽  
Shangzhen Zhou ◽  
Elizabeth P. Merricks ◽  
...  
Keyword(s):  
Low Dose ◽  
Hemophilia A ◽  
High Dose ◽  
Dependent Manner ◽  
Igg Antibodies ◽  
Single Chain ◽  
Spontaneous Bleeding ◽  
Aav Vector ◽  
Bleeding Episodes

Abstract Abstract 546 While adeno-associated virus (AAV) is a promising gene delivery vector, it has been challenging to deliver FVIII due to the large size of the FVIII cDNA and the high frequency of FVIII antibody formation in hemophilia A (HA) patients. We used two approaches to overcome the size limitation of AAV for FVIII: (1) two-chain delivery in which the canine FVIII (cFVIII) heavy chain (HC) is delivered in one AAV vector and the cFVIII light chain (LC) is delivered in a second AAV vector and (2) single chain delivery in which the B-domain deleted cFVIII cDNA with minimal regulatory elements is within one AAV vector. In the two-chain approach AAV-HC (4.0 Kb) and AAV-LC (3.9 Kb) with a liver specific promoter was co-injected at a dose of 6×1012 vector genomes/vector/kg or 1.25×1013vg/vector/kg using AAV8 or AAV9 via hepatic infusion. Five hemophilia A dogs treated with AAV-HC and AAV-LC expressed 0.5-11% cFVIII in a dose-dependent manner. The mean cFVIII activity based on Coatest assay for the low dose was 1.3% (>1220d)(Linus)(AAV8) and 0.6% (>1770d)(H19)(AAV9), while for the high dose it was 5.2% (800d)(F24)(AAV8) and 2.4% (>1270d)(Woodstock)(AAV9). One dog (J60) had a splenectomy due to a complication at the time of surgery and has maintained high levels of expression (mean 11.0%; >820d). The WBCT consistently remained at a mean of 17.6 min for low dose dogs and 13.7 min for high dose dogs compared to 8-12 min in normal dogs. Using novel reagents that we generated specific to cFVIII, we developed assays to detect cFVIII antigen levels and IgG antibodies. Despite receiving equal doses of each vector, at day 85 the cFVIII-LC antigen levels (71.7 ± 19.2 ng/ml) were >10-fold higher than would be predicted based on activity while the cFVIII-HC antigen levels (14.6 ± 9.2 ng/ml) were >3-fold higher than activity. Since functional FVIII synthesis relies on the co-transduction of AAV-HC and AAV-LC in the same cell, this suggests that only a portion of the vector co-transduces and expresses cFVIII in the same cell and that the light chain is secreted more efficiently than the HC. No IgG antibodies to cFVIII were detected at any time point in these dogs. Three dogs have maintained FVIII expression for >3.5 years and two dogs for >2 years with ongoing observation. No spontaneous bleeding episodes have been observed in these dogs for a cumulative observation of >16 years while >80 bleeding episodes would be expected during this time period. The second approach, the single chain delivery, overcomes the co-transduction requirement of the two-chain approach by ensuring that each transduced cell expresses functional FVIII. However, it is difficult to efficiently package the large 5.2 Kb single chain construct into an AAV vector. Since no significant differences were observed between AAV8 and AAV9 using the two-chain approach, we used AAV8 to deliver the single chain cFVIII by peripheral vein infusion at 2×1013vg/kg or 4×1013vg/kg. The mean cFVIII activity was 0.7% (>430d) for the low dose dog (L51) and 6.8% (>290d) and 2.2% (>110d) for the high dose dogs (M06, M50). cFVIII HC and LC ELISA showed that cFVIII antigen levels correlated with activity. WBCT was a mean of 19.1 min for L51, 15.3 min for M06 and 11.6 min for M50. No spontaneous bleeding episodes have been observed in these dogs. The high dose dogs had no IgG antibodies to FVIII. L51 had transient IgG antibodies to FVIII until d52 in the absence of a Bethesda titer. A rise in FVIII expression in L51 coincided with the disappearance of anti-cFVIII antibodies. Comparison of single chain and two-chain delivery of FVIII reveals that (1) long term therapeutic levels of cFVIII in a dose-dependent manner can be obtained with both delivery approaches; (2) circulating cFVIII antigen levels are >10-fold higher than activity in the two-chain delivery in contrast to single chain delivery in which antigen correlates with activity; and (3) high antigen levels may facilitate tolerance to FVIII in the setting of liver-directed gene transfer, since a transient non-inhibitory antibody was observed in only one dog with very low FVIII levels. Notably, no cellular toxicity due to continuous expression of various forms of FVIII was found in these animals based on long-term sustained FVIII expression levels and normal liver enzymes in all eight HA dogs. Further studies to characterize the immune responses to the transgene will define the optimal vector approach. These data will form the basis for clinical studies in humans with severe HA. Disclosures: No relevant conflicts of interest to declare.

Long Term Dose-Dependent Correction of Hemophilia A Dogs Using AAV-8 and AAV-9-Mediated FVIII Gene Transfer.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 999-999
Author(s):  
Denise E. Sabatino ◽  
Amy M. Lange ◽  
Melinda Mucci ◽  
Rita Sarkar ◽  
Aaron M. Dillow ◽  
...  
Keyword(s):  
Gene Transfer ◽  
Dose Group ◽  
Low Dose ◽  
Hemophilia A ◽  
Clotting Factor ◽  
High Dose ◽  
Functional Assay ◽  
Dependent Manner ◽  
Aav Vector ◽  
Dose Dependent

Abstract Hemophilia A (HA) is an X-linked bleeding disorder characterized by deficiency in clotting factor VIII (FVIII). Current treatment for hemophilia is protein replacement therapy while a gene-based therapy would provide continuous expression of even low levels of FVIII protein (>1% of normal) that is likely to improve the disease phenotype. It is challenging to utilize an AAV-mediated gene transfer approach for the FVIII cDNA (4.4kb) since the AAV vector can only efficiently accommodate a <5.3kb transgene cassette. The FVIII protein is composed of 2 chains -the heavy chain (HC) and the light chain (LC). FVIII undergoes proteolytic cleavage and processing of the 2 individual chains that form the active FVIII protein. In other studies in HA dogs (n=8), no dose-response and AAV serotype-dependent FVIII expression has been documented, which illustrates the difficulties in using a FVIII single-chain approach. We have utilized a 2-chain approach in which the 2.4kb LC cDNA is packaged in one AAV vector while the 2.5kb HC is packaged into a second AAV vector. Each construct contains a 695bp thyroxine-binding globulin gene promoter/enhancer fused to a 175bp intron along with a 263bp SV40 poly A signal. For this approach the LC and HC vectors packaged into either AAV8 or AAV9 were administered to HA dogs via the hepatic artery. Two male HA dogs received HC and LC in AAV8 and 2 male dogs received HC and LC in AAV9 at doses of 6x1012gc/vector/kg (low dose) or 1.25x1013gc/v/kg (high dose). At 150 days after vector infusion, the high dose group expressed FVIII at levels of 4.8% (AAV8) and 3% (AAV9) as detected by a functional assay (Coatest assay). FVIII remained stable for 797 days (AAV8) and >200 days (AAV9) (the longest time points to date) without any evidence of antibody formation to the transgene. In the low dose group at 150 days, FVIII levels were 1.5% (AAV8) and 0.5% (AAV9) cFVIII activity and were maintained in a follow up period of >150 days (AAV8) and >700 days (AAV9) without formation of antibodies to FVIII. Thus, no major differences between AAV8 and AAV9 vectors were observed. The transgene product is also functional based on shortening of whole blood clotting time (baseline values >50 min), in a dose-dependent manner, 10–15 min and 16–20 min for the high and low dose cohorts, respectively. Interestingly, high dose injection of AAV8 to 2 female HA dogs (1.25x1013 and 3x1013gc/v/kg) results in FVIII levels of 1–2%, which is consistent with data obtained in mice on the poor performance of AAV in mediating gene transfer to liver in female animals. Liver function tests and other blood chemistries were transiently elevated after the surgical procedure and were in normal limits within 4 days. Importantly, all dogs did not develop antibodies to FVIII. These findings suggest that FVIII chains efficiently assemble in vivo without increasing the protein immunogenicity. The 4 male dogs have remained asymptomatic with no spontaneous bleeds, whereas >20 bleeding episodes were expected for this group since untreated dogs require 5.5 plasma infusions/year. These data demonstrate for the first time, dose-dependent sustained expression of functional cFVIII in HA dogs by AAV8 and AAV9 vectors without formation of antibodies to cFVIII.

scholarly journals The Effect of Long-Term Low-Dose Atropine on Refractive Progression in Myopic Australian School Children

2021 ◽  
Vol 10 (7) ◽  
pp. 1444
Author(s):  
William Myles ◽  
Catherine Dunlop ◽  
Sally A. McFadden
Keyword(s):  
Low Dose ◽  
High Dose ◽  
Eye Drops ◽  
Myopia Progression ◽  
At Risk Children ◽  
Slow Group ◽  
Blue Eyes ◽  
Global Population ◽  
Axial Growth

Myopia will affect half the global population by 2050 and is a leading cause of vision impairment. High-dose atropine slows myopia progression but with undesirable side-effects. Low-dose atropine is an alternative. We report the effects of 0.01% or 0.005% atropine eye drops on myopia progression in 13 Australian children aged between 2 and 18 years and observed for 2 years without and up to 5 years (mean 2.8 years) with treatment. Prior to treatment, myopia progression was either ‘slow’ (more positive than −0.5D/year; mean −0.19D/year) or ‘fast’ (more negative than −0.5D/year; mean −1.01D/year). Atropine reduced myopic progression rates (slow: −0.07D/year, fast: −0.25D/year, combined: before: −0.74, during: −0.18D/year, p = 0.03). Rebound occurred in 3/4 eyes that ceased atropine. Atropine halved axial growth in the ‘Slow’ group relative to an age-matched model of untreated myopes (0.098 vs. 0.196mm/year, p < 0.001) but was double that in emmetropes (0.051mm/year, p < 0.01). Atropine did not slow axial growth in ‘fast’ progressors compared to the age-matched untreated myope model (0.265 vs. 0.245mm/year, p = 0.754, Power = 0.8). Adverse effects (69% of patients) included dilated pupils (6/13) more common in children with blue eyes (5/7, p = 0.04). Low-dose atropine could not remove initial myopia offsets suggesting treatment should commence in at-risk children as young as possible.

scholarly journals BAFF signaling drives interstitial transformation of mouse renal tubular epithelial cells in a Pin1-dependent manner

2021 ◽  
Author(s):  
Haiyan Xu ◽  
Dan Song ◽  
Renfang Xu ◽  
Xiaozhou He
Keyword(s):  
Flow Cytometry ◽  
Epithelial Cells ◽  
Biological Activities ◽  
High Dose ◽  
Dependent Manner ◽  
Tubular Epithelial Cells ◽  
Renal Tubular Epithelial Cells ◽  
Aberrant Expression ◽  
Renal Tubular

AbstractAberrant expression of B cell–activating factor belonging to TNF superfamily (BAFF) and its receptors results in abnormal biological activities in hematopoietic and non-hematopoietic cells and is closely associated with the occurrence and development of various diseases. However, the biological significance and potential mechanisms underlying BAFF signaling in renal tubular epithelial cells (RTECs) remain unknown. This study aimed to investigate the biological role of BAFF signaling in RTECs. Mice primary RTECs were applied. The proliferation status and apoptotic rates were examined by MTS assay and flow cytometry, respectively. The expression of BAFF and its receptors was analyzed via flow cytometry and sodium ion transport function, and cytokeratin-18 expression was detected through immunofluorescence staining. In addition, Pin1 was knocked down via siRNA and its expression was assessed through reverse transcription PCR. Lastly, western blotting was performed to analyze E-cadherin, ɑ-SMA, and Pin1 expression. Results suggested that BAFF-R was significantly upregulated upon IFN-γ stimulation, and enhancement of BAFF signaling promoted cell survival and reduced their apoptotic rate, while simultaneously reducing the epithelial phenotype and promoting the interstitial transformation of cells. Furthermore, Pin1 was significantly increased, along with the upregulation of BAFF signaling in the RTECs, and participated in interstitial transformation induced by BAFF signaling. Collectively, the present results elucidate the potential mechanism of loss of normal function of RTECs under long-term high dose of BAFF stimulation provides a potential therapeutic target for renal interstitial fibrosis, and underlining mechanisms of shortening of long-term outcomes of kidney allografts via augmenting of BAFF signaling.

Enlargement of cerebrospinal fluid spaces in long-term benzodiazepine abusers

1987 ◽  
Vol 17 (4) ◽  
pp. 869-873 ◽  
Author(s):  
C. Schmauss ◽  
J.-C. Krieg
Keyword(s):  
Low Dose ◽  
Matched Control ◽  
Control Group ◽  
High Dose ◽  
Withdrawal Therapy ◽  
The Mean ◽  
Dose Dependent ◽  
Dose Dependent Effect ◽  
Age And Sex

SynopsisIn 17 benzodiazepine (BDZ) dependent in-patients a CT scan was performed before initiation of withdrawal therapy. The evaluation of the ventricular to brain ratio (VBR) by standardized and computerized measurements revealed significantly higher mean VBRs for both high-and low-dose BDZ-dependent patients compared to the mean VBR of an age- and sex-matched control group. In addition, the mean VBR of high-dose BDZ-dependent patients (N = 8) was significantly higher than the mean VBR of low-dose BDZ-dependent patients (N = 9). This difference could not be accounted for by the age of the patients or duration of BDZ-dependency and, therefore, suggests a dose-dependent effect of BDZs on the enlargement of internal CSF-spaces. On the other hand, higher values for the width of external CSF-spaces were found to be related to increasing age of the patients and duration of BDZ-dependency.

Effect of gallic acid on the reproduction of adolescent male Brandt’s vole (Lasiopodomys brandtii)

2021 ◽  
Author(s):  
Xin Dai ◽  
Xiao-Feng Sun ◽  
Ai-Qin Wang ◽  
Wanhong Wei ◽  
Sheng-Mei Yang
Keyword(s):  
Gallic Acid ◽  
Low Dose ◽  
Regulatory Protein ◽  
Antioxidant Properties ◽  
Adolescent Male ◽  
Seminiferous Tubules ◽  
High Dose ◽  
Mrna Levels ◽  
Dependent Manner ◽  
Lasiopodomys Brandtii

Gallic acid (GA), a phenol that is present in various plants, potentially contains antioxidant properties. This study aimed to investigate the effects of GA on the reproduction of adolescent male Brandt’s voles (Lasiopodomys brandtii (Radde, 1861)). Antioxidant levels and apoptosis in the testis, as well as reproductive physiology, were evaluated in adolescent males treated with GA. The results showed that a low dose of GA enhanced relative epididymis weight and the sperm density in the epididymis, increased the mRNA levels of steroidogenic acute regulatory protein in the testis, and reduced the percentages of abnormal and dead sperm. In addition, a low dose of GA significantly increased the levels of superoxide dismutase, catalase, and glutathione peroxidase, and decreased the level of malondialdehyde in the testis, as well as the mRNA and protein levels of the apoptosis related gene, caspase-3. However, a high dose of GA sharply reduced the average diameter of the seminiferous tubules compared to a low dose. Collectively, these findings demonstrate that GA treatment during puberty affects the reproductive responses of male Brandt’s voles in a dose-dependent manner by regulating antioxidant levels and apoptosis.

Comparative Effects of Staphylokinase and Alteplase in Rabbit Bleeding Time Models

1996 ◽  
Vol 75 (05) ◽  
pp. 816-819 ◽  
Author(s):  
Steven Vanderschueren ◽  
Désiré Collen
Keyword(s):  
Thrombolytic Therapy ◽  
Low Dose ◽  
Bleeding Time ◽  
Tissue Type ◽  
High Dose ◽  
Time Model ◽  
Spontaneous Bleeding ◽  
Tissue Type Plasminogen Activator ◽  
Type Plasminogen Activator ◽  
Combined Administration

Summary Background: The pathogenesis of bleeding associated with thrombolytic therapy remains largely unknown, although spontaneous bleeding appears to correlate with bleeding time prolongation. Here, the comparative effects on cuticle bleeding times (CBT) and ear puncture bleeding times (EBT) of recombinant staphylokinase (Sak) and alteplase (recombinant tissue-type plasminogen activator, rt-PA) at equivalent doses, alone and in combination with aspirin and heparin, were studied in rabbits. Methods and Results: Groups of 4 to 9 rabbits were allocated to one of the 8 following intravenous infusions: saline; aspirin 15 mg/kg and heparin - 100 IU/kg bolus and 10 IU/kg infusion over one hour; 1.5 mg/kg rt-PA; 1.5 mg/kg rt-PA plus aspirin and heparin; 4.5 mg/kg rt-PA; 0.5 mg/kg Sak; 0.5 mg/kg Sak plus aspirin and heparin and 1.5 mg/kg Sak. Bleeding times were determined 30 and 15 min before and 5,15,30 and 60 min after the administration over one min of saline, rt-PA or Sak, by simultaneously severing a nail cuticle (CBT) and by puncturing the ear (EBT). Bleeding times were unaffected by saline and by both doses of Sak in monotherapy. Heparin-aspirin and low dose rt-PA significantly lengthened EBT but not CBT. Both CBT and EBT were significantly prolonged (to a mean of >4 times pretreatment at 5 min) after high-dose rt-PA and after the combined administration of heparin and aspirin with either Sak or rt-PA. rt-PA provoked significantly longer bleeding than Sak in the CBT (p = 0.001; mean estimated difference = 23 min), but not in the EBT. rt-PA but not Sak degraded plasma fibrinogen dose-dependently. CBT correlated inversely with fibrinogen (r = −0.66, p = 0.001) but EBT did not. Conclusions: At equivalent doses Sak displays a significantly higher fibrin specificity and prolongs bleeding time less than rt-PA, particularly in the nail cuticle bleeding time model in which larger vessels are injured that require fibrinogen for hemostasis.

scholarly journals Vedolizumab Treatment for Ulcerative Colitis in an Elderly Multimorbid Patient with Hemophilia A

2017 ◽  
Vol 11 (3) ◽  
pp. 774-779 ◽  
Author(s):  
Holger Schäffler ◽  
Astrid Huth ◽  
Georg Lamprecht ◽  
Olaf Anders
Keyword(s):  
Ulcerative Colitis ◽  
Factor Viii ◽  
Hemophilia A ◽  
Point Of View ◽  
Recurrent Bleeding ◽  
St Segment Elevation ◽  
Primary Hemostasis ◽  
Bowel Diseases ◽  
Bleeding Episodes

The treatment of inflammatory bowel diseases (IBD) can be challenging, especially in elderly multimorbid patients. Since incidence and prevalence rates of IBD are rising steadily, treatment of older patients with relevant and also rare comorbidities will be of increasing relevancy for caregivers. Here we report on a 74-year-old multimorbid patient with severe ulcerative colitis (UC) and hemophilia A. Because of the chronic active disease, therapy with a tumor necrosis factor-α inhibitor was started. He suffered from a severe infectious complication (pneumonia) under therapy with infliximab. The therapy was changed to vedolizumab, with which the patient stayed in long-term clinical and endoscopic remission. Because the patient had a non-ST-segment elevation myocardial infarction in April 2016, he received dual platelet inhibitor therapy with aspirin and clopidogrel. Because of consecutive aspirin intolerance, the therapy was changed to clopidogrel monotherapy. Although the UC was treated appropriately with vedolizumab and the patient was in endoscopic mucosal remission, recurrent bleeding episodes from multiple inflammatory pseudopolyps occurred. The bleeding episodes resolved quickly after immediate treatment with factor VIII (Kogenate®). In conclusion, we describe the first patient in the literature with UC and hemophilia A who stayed in long-term remission under therapy with vedolizumab. From our point of view, vedolizumab can be safely administered in the setting of UC and hemophilia A. Antiplatelet drugs which inhibit primary hemostasis must be used with caution in this setting. Bleeding episodes can be treated safely and effectively with factor VIII (Kogenate®).

scholarly journals Efficacy and safety of the drug Octofactor in prophylactic treatment in patients with severe haemophilia A

2018 ◽  
Vol 5 (3) ◽  
pp. 60-73 ◽  
Author(s):  
T. A. Andreeva ◽  
V. Yu. Zorenko ◽  
I. L. Davydkin ◽  
V. N. Konstantinova ◽  
O. E. Zalepukhina ◽  
...  
Keyword(s):  
Hemophilia A ◽  
Bleeding Episode ◽  
Coagulation Factor ◽  
Preventive Treatment ◽  
Haemophilia A ◽  
Severe Haemophilia ◽  
Efficacy And Safety ◽  
Spontaneous Bleeding ◽  
Bleeding Episodes ◽  
Blood Coagulation Factor Viii

Relevance.The development of a new recombinant blood coagulation factor VIII preparation is a promising step towards optimizing the treatment of hemophilia A. An introduction of a new medication into clinical practice precedes a clinical trials to evaluate the efficacy and safety.Materials and methods.The efficacy and safety of the domestic recombinant B-domain deleted blood coagulation factor VIII (FVIII) (moroctocog alfa, Octofactor®, JSC “GENERIUM”) were studied in the preventive treatment of 31 patients aged 21 to 52 years with severe haemophilia A. The Octofactor was administered in doses of 40 ± 5 IU/kg 3 times per week at intervals of at least 48 hours for 21 ± 1 weeks.Results.The efficacy of therapy was evaluated in 30 patients, since 1 patient refused to participate in the trial after the first injection of the study medication. There were registered 43 episodes of bleeding among 11 patients in the course of the preventive treatment with Octofactor. The average number of bleeding episodes was 1.4 ± 2.58. There were 43 bleeding episodes, 9 (20.9 %) of them were posttraumatic, 34 (79.1 %) of them were spontaneous. The average number of the spontaneous bleeding episodes (a major criterion of the efficacy) was 1.13 ± 2.19, which showed a low incidence of exacerbations of the hemorrhagic syndrome in the course of preventive treatment with Octofactor. Among all registered bleeding episodes there were 6 (14 %) mild episodes, 37 (86 %) moderate episodes. Among all spontaneous bleedings there were 6 mild episodes (17.6 %), 28 (82.4 %) moderate episodes. All posttraumatic bleedings were moderate. The vast majority (36, or 83.7 %) of bleeding episodes were stopped with administration of the Octofactor. The average number of administrations of the Octofactor for arresting 1 bleeding episode was 1.2 ± 0.56, for 1 spontaneous bleeding episode – 1.2 ± 0.59. On average, it was required to administer 3534.9 ± 2329.02 IU of the Octofactor to stop 1 episode of bleeding. In the vast majority of patients with severe hemophilia A (83.3–86.7 %),  the remaining activity FVIII was 1 % or more after the administration of the Octofactor in 48 hours. The total amount of the Octofactor, introduced for the prevention of bleeding, was 6,107,000 IU, to stop bleeding – 152,000 IU. The safety of therapy was evaluated in 31 patients. There were recorded 25 adverse events (AE) in 17 patients. Among them the laboratory ones prevailed in 23 (92 %) cases, which is not associated with the use of the trial medication. There were noted nausea and an unpleasant aftertaste in the mouth in 1 patient during the first administration of the Octofactor, and therefore he refused to continue to participate in the trial. Causality 2 AE with the study drug was regarded as definite. Such AE are expected and described in the instructions to the preparation. All AE were not serious and mild and resolved without outcomes. There were no presented thromboembolic events and immunogenic reactions.Conclusions.The obtained data testify to the efficacy and safety of the Octofactor both for preventive measures and for stopping bleeding in adult patients with severe hemophilia A.

scholarly journals Effects of replacement therapies with clotting factors in patients with hemophilia: A systematic review and meta-analysis

PLoS ONE ◽  
2022 ◽  
Vol 17 (1) ◽  
pp. e0262273
Author(s):  
Carolina J. Delgado-Flores ◽  
David García-Gomero ◽  
Stefany Salvador-Salvador ◽  
José Montes-Alvis ◽  
Celina Herrera-Cunti ◽  
...  
Keyword(s):  
Low Dose ◽  
Prophylactic Treatment ◽  
Hemophilia A ◽  
Clotting Factor ◽  
High Dose ◽  
Bleeding Rate ◽  
Episodic Treatment ◽  
Grade Methodology ◽  
Inform Decision Making ◽  
Intermediate Dose

Background Different prophylactic and episodic clotting factor treatments are used in the management of hemophilia. A summarize of the evidence is needed inform decision-making. Objective To compare the effects of factor replacement therapies in patients with hemophilia. Methods We performed a systematic search in PubMed, Central Cochrane Library, and Scopus. We included randomized controlled trials (RCTs) published up to December 2020, which compared different factor replacement therapies in patients with hemophilia. Random-effects meta-analyses were performed whenever possible. The certainty of the evidence was assessed using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) methodology. The study protocol was registered in PROSPERO (CRD42021225857). Results Nine RCTs were included in this review, of which six compared episodic with prophylactic treatment, all of them performed in patients with hemophilia A. Pooled results showed that, compared to the episodic treatment group, the annualized bleeding rate was lower in the low-dose prophylactic group (ratio of means [RM]: 0.27, 95% CI: 0.17 to 0.43), intermediate-dose prophylactic group (RM: 0.15, 95% CI: 0.07 to 0.36), and high-dose prophylactic group (RM: 0.07, 95% CI: 0.04 to 0.13). With significant difference between these subgroups (p = 0.003, I2 = 82.9%). In addition, compared to the episodic treatment group, the annualized joint bleeding rate was lower in the low-dose prophylactic group (RM: 0.17, 95% CI: 0.06 to 0.43), intermediate-dose prophylactic group (RM of 0.14, 95% CI: 0.07 to 0.27), and high-dose prophylactic group (RM of 0.08, 95% CI: 0.04 to 0.16). Without significant subgroup differences. The certainty of the evidence was very low for all outcomes according to GRADE methodology. The other studies compared different types of clotting factor concentrates (CFCs), assessed pharmacokinetic prophylaxis, or compared different frequencies of medication administration. Conclusions Our results suggest that prophylactic treatment (at either low, intermediate, or high doses) is superior to episodic treatment for bleeding prevention. In patients with hemophilia A, the bleeding rate seems to have a dose-response effect. However, no study compared different doses of prophylactic treatment, and all results had a very low certainty of the evidence. Thus, future studies are needed to confirm these results and inform decision making.

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