[Novel treatment strategies for acquired hemophilia A].

Acquired hemophilia A (AHA) is a bleeding disorder caused by autoantibody (inhibitor) production targeting blood coagulation factor VIII (FVIII). It is characterized by sudden onset, and often causes extensive and severe bleeding in soft tissue. Acquired hemophilia A is diagnosed when coagulation tests show normal PT, prolonged APTT, decreased FVIII activity, normal VWF activity, and positive FVIII inhibitor. Hemostatic therapy mainly consists of bypass therapy, which activates the extrinsic coagulation pathway, bypassing the need for FVIII or factor IX. Emicizumab, a bispecific antibody that substitutes for FVIII function, can be used to prevent bleeding. Immunosuppressive therapy is necessary to suppress or eradicate inhibitors. The majority of patients go into remission with treatment, but some die from bleeding symptoms or infections associated with immunosuppressive therapy.

Comparison between the impact of tenofovir alafenamide and that of abacavir on rapid kidney function decline: A retrospective observational study.

OBJECTIVES: To compare the impact of tenofovir alafenamide (TAF) on the slope of the estimated glomerular filtration rate (eGFR) with that of abacavir in Japanese patients living with HIV infection. METHODS: The participants in this single-centre, retrospective, observational study were Japanese patients with HIV infection who started antiretroviral therapy with TAF/emtricitabine or abacavir/lamivudine or were switched from tenofovir disoproxil fumarate/emtricitabine to TAF/emtricitabine or abacavir/lamivudine (anchor drugs remained constant) between January 2012 and December 2020. The eGFR slope was defined as the regression coefficient between eGFR and time. The study outcome was rapid kidney function decline (RKFD; eGFR slope < -5 mL/min/1.73 m2 /year). The adjusted effect of TAF on the eGFR slope was compared with that of abacavir using multivariate logistic regression analysis. RESULTS: The study included 184 patients (with 2835 eGFR data points). The median duration of exposure to TAF or abacavir was 2.6 years [interquartile range (IQR): 1.7-3.3], and the median eGFR slope was -4.1 mL/min/1.73 m2 /year (IQR: -6.4 to -1.2). In all, 72 patients (39%) experienced RKFD. Patients receiving TAF were more likely to experience RKFD (adjusted odds ratio = 3.74) than those receiving abacavir. There was a significant independent association between baseline eGFR and RKFD. CONCLUSIONS: These findings suggest that renal function should be monitored carefully after the initiation of TAF in Japanese patients with HIV infection.

Haemophilia and cardiovascular disease in Japan: Low incidence rates from ADVANCE Japan baseline data.

INTRODUCTION: With the increasing life expectancy of people with haemophilia, the risk of cardiovascular disease (CVD) and thrombotic events has become a growing concern. Longitudinal studies on the incidence and risk factors of CVD in this population are limited, and optimal prevention and treatment strategies are yet to be established. AIM: This study aimed to present the baseline data of a prospective longitudinal study focusing on a subset of Japanese patients with haemophilia, specifically investigated the incidence, risk factors and treatment modalities for CVD and thrombotic diseases in people aged 40 years in Japan over 10 years through the ADVANCE Japan study. METHODS: The ADVANCE Japan study is a prospective multicentre cohort study involving 600 adult individuals with haemophilia A/B aged 40 years in Japan. The primary endpoint was the incidence of CVD, with secondary endpoints encompassing anticoagulant use, mortality rates, and comparison with the general population. RESULTS: Baseline data from the 600 participants revealed that thrombotic events occurred in 13 individuals (2.2%), mostly in those with haemophilia A. Atrial fibrillation was observed in 11 participants (1.8%). Hypertension and dyslipidaemia were identified as the prevalent risk factors. Various prophylactic treatments were employed, and no severe bleeding events were observed during the study period. CONCLUSION: This study provides vital baseline data for a 10-year prospective investigation of CVD and thrombotic disease risk in people with haemophilia. These findings will contribute to refining prevention and treatment approaches and improving patients' quality of life.

Clinical conditions and risk factors for inhibitor-development in patients with haemophilia: A decade-long prospective cohort study in Japan, J-HIS2 (Japan Hemophilia Inhibitor Study 2).

BACKGROUND: Inhibitor-development is a serious complication in patients with haemophilia (PwH). Previous studies reported that therapeutic and genetic factors could be associated with these alloantibodies. Relevant clinical features such as genetic-background and different treatment regimens in Japan remain unclear, however. AIMS: To analyse a nation-wide Japanese registry for PwH, and to examine risk factors for inhibitor-development. METHODS AND RESULTS: Newly diagnosed patients with haemophilia A (PwHA) or haemophilia B (PwHB) without inhibitors after 2007, and with treatment records traceable from 0 to 75 exposure days (ED), were enrolled in the Japan Hemophilia Inhibitor Study 2 (J-HIS2) initiated in 2008. Of 417 patients (340 PwHA, 77 PwHB) from 46 facilities, 83 (76 PwHA, 7 PwHB) were recorded with inhibitors by July 2020. Inhibitors were observed in 31.0% of severe PwHA, 8.0% moderate and 1.6% mild and in 17.1% of severe PwHB. The majority of inhibitors (89.7% in severe PwHA and 71.4% in severe PwHB) were detected on or before 25ED (median 12ED in PwHA and 19ED in PwHB). Genotyping in these severe patients identified an association between inhibitor-development and null variants of F8 (P < .01) or F9 (P < .05). A lower incidence of inhibitors was recorded in severe PwHA treated with prophylaxis than in those treated on-demand (P < .01). A past-history of intracranial-haemorrhage appeared to be associated with inhibitor-development, while FVIII-concentrates infusion and routine vaccination on the same day was not related to inhibitor-development. CONCLUSION: The J-HIS2 study has identified significant clinical variables associated with inhibitor-development in Japanese PwH, consistent with other global studies.

Effect of switching from tenofovir disoproxil fumarate to tenofovir alafenamide on estimated glomerular filtration rate slope in patients with HIV: A retrospective observational study.

INTRODUCTION: There is limited data on the effects of switching from tenofovir disoproxil fumarate (TDF) to tenofovir alafenamide (TAF) on estimated glomerular filtration rates (eGFR) slope in patients with human immunodeficiency virus (HIV) infection. This study aimed to compare the eGFR slope when administering TDF and TAF and to investigate the predictors of improvement in eGFR slope after switching from TDF to TAF. METHODS: We conducted a single-center, retrospective, observational study in Japanese patients with HIV infection who switched the antiretroviral drug from TDF to TAF. eGFR was calculated using serum cystatin C. The eGFR slope was defined as the regression coefficient between eGFR and time. Differences between eGFR slope during TDF and TAF administration were compared using Wilcoxon signed rank test. A stepwise logistic regression model was used to examine the associations between improvement of eGFR slope after switching from TDF to TAF and various parameters. RESULTS: Overall, 63 patients (656 eGFR) were included in the analysis. The median analyzed durations of TDF and TAF exposures were 1.6 and 1.5 years, respectively. There were no significant differences between eGFR slope during TDF and TAF periods (median: 0.6 vs. 4.0 mL/min/1.73 m2/year, p = 0.165). The eGFR slopes during the TDF period and while switching from TDF to TAF were independent predictors of improvement in eGFR slope after switching from TDF to TAF. CONCLUSIONS: The results suggest that patients with poor renal function and those with progressive worsening during TDF administration would benefit from switching to TAF.

Impact of the use of hydroxyethyl starch in granulocyte apheresis using Spectra Optia.

OBJECTIVES: To determine the impact of the use of hydroxyethyl starch (HES) in granulocyte apheresis using Spectra Optia. BACKGROUND: Granulocyte transfusion (GT) is a therapeutic option for neutropenic patients with severe bacterial or fungal infections. Recent studies in emergency medicine have shown the potential risk of using HES, which is routinely used in granulocyte apheresis to increase yield by sedimenting red blood cells. We hypothesized that the use of a newer device (Spectra Optia) would spare the need for HES. METHODS: We retrospectively compared granulocyte apheresis with HES (HES group, n = 89) and without HES (non-HES group, n = 36) using Spectra Optia. RESULTS: The granulocyte yield was significantly higher in the HES group (7.3 × 1010 vs. 2.0 × 10, p < 0.01) and was attributed to the difference in collection efficiency (36% vs. 7.7%, p < 0.01). The absolute neutrophil count on the following morning of GT was significantly higher in the HES group than in the non-HES group (2460/µl vs. 505/µl, p < 0.01). There were no significant differences in the occurrence of adverse events between the HES and non-HES groups. The renal function was unchanged in both groups after apheresis. CONCLUSIONS: We demonstrated that the advantage of using HES remained unchanged in granulocyte apheresis using Spectra Optia.

Ischaemic events are rare, and the prevalence of hypertension is not high in Japanese adults with haemophilia: First multicentre study in Asia.

INTRODUCTION: With the increasing life expectancy of patients with haemophilia (PWH), the number of PWH with age-related comorbidities, such as ischaemic events, is increasing. AIM: We conducted this multicentre observational study to identify the risk factors for major ischaemic events in PWH. METHODS: This study was the first multicentre observational study, conducted with the participation of five haemophilia treatment centres in Japan, conducted in ≥30-year-old adult PWH. The latest data recorded in the medical charts between 1 January and 31 December 2016 were reviewed. Healthcare data collected from the National Health and Nutrition Survey were used as the control data. RESULTS: Data of a total of 711 patients were collected. Only two PWH (0.3%) had a history of ischaemic events. Age-adjusted analysis indicated that the prevalence of hypertension defined as a blood pressure of 140/90 mm Hg or over was similar in the PWH to that in the males of the general population. However, when hypertension was defined more strictly (≥130/85 mm Hg), the prevalence was significantly lower in PWH than in the general male population. The hypertension in PWH was associated with the age, BMI, CKD, HIV infection and inhibitors. In particular, the odds ratio for the presence of inhibitors was high (odds ratio = 7.529). CONCLUSION: Whether the present results can be attributed to Japanese ethnicity or to the presence of haemophilia per se remains uncertain. We propose to initiate a prospective study for further investigation.

11ß-hydroxysteroid dehydrogenase type 1 is associated with antiretroviral therapy-induced increase in low-density lipoprotein cholesterol
.

OBJECTIVE: To investigate the association between 11ß-hydroxysteroid dehydrogenase type 1 (11ß-HSD1) activity and antiretroviral therapy (ART)-induced increase in low-density lipoprotein cholesterol (LDL). MATERIALS AND METHODS: We enrolled 62 patients and used liquid chromatography-tandem mass spectrometry to measure 11ß-HSD1 activity, which was expressed as a ratio of the sum of urinary tetrahydrocortisol and allo-tetrahydrocortisol concentrations to urinary tetrahydrocortisone concentration. Patient data, including baseline laboratory values, were extracted from medical records for logistic regression analyses of factors associated with LDL increase during ART. The cutoff 11ß-HSD1 activity ratio associated with the LDL increase during ART was determined using receiver operator characteristic (ROC) curve analysis. RESULTS: The LDL level increased significantly from 88.8 mg/dL before ART to 106.7 mg/dL during ART (p = 0.04). Additionally, patients with increased LDL tended to have a higher 11ß-HSD1 activity ratio (1.59 vs. 1.21, p = 0.06) and longer duration of ART (13.9 vs. 10.2 months, p = 0.07) than patients with unchanged or decreased LDL. The cutoff 11ß-HSD1 activity ratio was 1.226. Results of the univariate logistic regression analysis suggested that 11ß-HSD1 activity ratio ≥ 1.226 was associated with LDL increase during ART (p = 0.011), with an odds ratio of 8.000. CONCLUSION: This study revealed the possible association between 11ß-HSD1 activity and ART-induced LDL increase. The findings of this study suggest that 11ß-HSD1 could be a useful drug target for the treatment of ART-induced hyperlipidemia.

A potential drug interaction between phenobarbital and dolutegravir: A case report.

In this report, we describe a human immunodeficiency virus (HIV)-infected patient in whom changes in phenobarbital (PB) dosage resulted in associated changes in plasma concentrations of dolutegravir (DTG). His plasma concentrations of DTG were 0.934, 0.584, 1.003 and 3.25 µg/mL, respectively, with concomitant daily PB doses of 40, 70, 30 and 0 mg, respectively. This case suggests that PB can lead to a remarkable reduction in the plasma concentration of DTG in a dose-dependent manner.

[Diagnosis and management of von Willebrand disease].

von Willebrand disease (VWD) is an inherited bleeding disorder resulting from either a quantitative or a qualitative deficiency in the plasma glycoprotein von Willebrand factor (VWF). A diagnosis of VWD can be made when a patient presents with appropriate bleeding and VWF <30 IU/dl. However, persons with VWF levels of 30-50 IU/dl cannot be precluded from the diagnosis of VWD. Desmopressin acetate (DDAVP) or VWF-containing factor VIII (pdVWF/FVIII) concentrate is used for treating VWD. The effect of DDAVP varies among individuals; a trial should be performed while in a nonbleeding state. For patients in whom DDAVP is invalid or those that require long-term management of hemostasis, pdVWF/FVIII is administered. The treatment of the hype rmenorrhea is the hope of every pregnant patient with VWD. When a patient with VWD becomes pregnant, VWF and FVIII should be regularly monitored throughout pregnancy. During childbirth, pdVWF/FVIII concentrate should be administered to achieve VWF and FVIII levels of ≥50 IU/dl before delivery.

The association between urinary liver-type fatty acid-binding protein and chronic kidney disease classification in HIV-infected Japanese patients.

BACKGROUND: Renal dysfunction is recognized with increasing frequency among the noninfectious comorbidities associated with human immunodeficiency virus (HIV) infection. Urinary liver-type fatty acid-binding protein (L-FABP) has been shown to be a new biomarker to screen for not only tubulointerstitial damage but also kidney dysfunction. METHODS: We performed a cross-sectional study to determine the association between the urinary L-FABP and chronic kidney disease (CKD) among 77 HIV-infected Japanese patients by backward-stepwise multivariable logistic regression. RESULTS: The prevalence of individuals in the low risk was 80 %. Urinary L-FABP level was not associated with antiretroviral therapy and tenofovir disoproxil fumarate. On the other hand, urinary L-FABP level was independently associated with the CKD classification. CONCLUSION: Urinary L-FABP may be used as an adjunct to diagnose the CKD stage.

Quality of life of people living with HIV compared with that of the general population in Japan.

OBJECTIVE: To evaluate the health-related quality of life (HRQOL) of people living with HIV (PLWH) in Japan. METHODS: A cross-sectional comparative study was conducted between June and December 2016 on PLWH. HRQOL was assessed using the Japanese version of the Short Form-36 Health Survey questionnaire (SF-36), and the three-component model of SF-36 scores was used. The values from the present study were compared with the published general Japanese values. Multivariate analysis was performed to identify the independent factors associated with the HRQOL of PLWH. RESULTS: A total of 151 PLWH were enrolled in the present study. Six out of the eight subscales were significantly lower than the normative data. With respect to the summary scores, compared with those in the general population, the physical component summary score (PCS) was significantly higher in PLWH, although the mental and social/role component summary scores (MCS and RCS, respectively) were lower. Older Age was independently related to lower PCS; formal employment and higher CD4 counts were independently related to higher PCS. The factor associated with lower MCS was taking psychoactive drug(s). Formal employment was independently associated with higher RCS; taking psychoactive drug(s) was independently associated with lower RCS. CONCLUSIONS: The physical HRQOL of PLWH was slightly higher; however, the mental and social/role HRQOL were slightly lower than in the general population in Japan.

Diagnosis and treatment of congenital and acquired hemophilia.

In recent years, the treatment of congenital hemophilia is a transition period for treatment using extended half-life clotting factor formulations. Although the half-life of these formulations is longer than that of the standard formulations, the strength and rate of the effect remain unchanged. Therefore, it is thought that we can adapt to any kind of case if we treat various kinds of plans within the insurance adaptation. Furthermore, the factor VIII-mimetic bispecific antibody has also been currently developed as a therapeutic drug for hemophilia A. The antibody has a long half-life of approximately 30 days, is not neutralized by inhibitors, and can be subcutaneously administered. Acquired hemophilia A (AHA) is a disorder characterized by bleeding caused by autoantibodies that are developed against factor VIII. In recent years, the diagnostic method and treatment for AHA have undergone no major change. The major symptoms of AHA-subcutaneous bleeding and muscle hemorrhage-differ from those of congenital hemophilia. In AHA, PT and VWF activities are normal, APTT is extended, factor VIII activity is decreased, and factor VIII inhibitor is positive. Bypassing agents are the mainstay of hemostasis treatment, and immunosuppressive therapy is essential for inhibitor eradication.

The prevalence of neutralizing antibodies against adeno-associated virus capsids is reduced in young Japanese individuals.

Pre-existing antibodies against adeno-associated virus (AAV), caused by natural AAV infections, interfere with recombinant AAV vector-mediated gene transfer. We studied the prevalence of neutralizing antibodies against AAV serotypes 1, 2, 5, 8, and 9 in healthy subjects (n = 85) and hemophilia patients (n = 59) in a Japanese population. For healthy subjects, the prevalence of neutralizing antibodies against AAV serotypes 1, 2, 5, 8, and 9 was 36.5%, 35.3%, 37.6%, 32.9%, and 36.5%, respectively, while that in hemophilia patients was 39.7%, 28.8%, 35.6%, 32.9%, and 27.4%, respectively. There was no difference in the prevalence of neutralizing antibody against each AAV serotype between the healthy subjects and the hemophilia patients. The prevalence of neutralizing antibodies against all AAV serotypes increased with age in both healthy subjects and hemophilia patients. High titers of neutralizing antibodies against AAV2 (≥1:224) and AAV8 (≥1:224) were more evident in older individuals (≥42 years old). Approximately 50% of all screened individuals were seronegative for neutralizing antibodies against each AAV tested, while approximately 25% of individuals were seropositive for each AAV serotype tested. The prevalence of seronegativity for all AAV serotypes was 67.0% (healthy subjects, 68.6%; hemophilia patients, 65.0%) and 18.6% (healthy subjects, 20.5%; hemophilia patients, 15.7%) in young (<42 years old) and older subjects (≥42 years old), respectively. The findings from this study suggested that young subjects are more likely to be eligible for gene therapy based on AAV vectors delivered via an intravascular route because of the low prevalence of antibodies to AAV capsids.

Timing of Assessment of Humoral and Cell-Mediated Immunity after Influenza Vaccination.

Assessment of the immune response to influenza vaccines should include an assessment of both humoral and cell-mediated immunity. However, there is a lack of consensus regarding the timing of immunological assessment of humoral and cell-mediated immunity after vaccination. Therefore, we investigated the timing of immunological assessments after vaccination using markers of humoral and cell-mediated immunity. In the 2018/2019 influenza season, blood was collected from 29 healthy adults before and after vaccination with a quadrivalent inactivated influenza vaccine, and we performed serial measurements of humoral immunity (hemagglutination inhibition [HAI] and neutralizing antibody [NT]) and cell-mediated immunity (interferon-gamma [IFN-γ]). The HAI and NT titers before and after vaccination were strongly correlated, but no correlation was observed between the markers of cell-mediated and humoral immunity. The geometric mean titer and geometric mean concentration of humoral and cellular immune markers increased within 2 weeks after vaccination and had already declined by 8 weeks. This study suggests that the optimal time to assess the immune response is 2 weeks after vaccination. Appropriately timed immunological assessments can help ensure that vaccination is effective.

Final Analysis Results from the AGEHA Study: Emicizumab Prophylaxis for Acquired Hemophilia A with or without Immunosuppressive Therapy.

BACKGROUND: Primary analysis of the phase III AGEHA study suggested a favorable benefit-risk profile for emicizumab prophylaxis in patients with acquired hemophilia A (PwAHA); however, only patients undergoing immunosuppressive therapy (IST) (Cohort 1) were included. OBJECTIVES: To present final analysis results of AGEHA, including data on IST-ineligible patients (Cohort 2) and on long-term prophylaxis with emicizumab. METHODS: For patients in both Cohorts 1 and 2, emicizumab was administered subcutaneously at 6 mg/kg on Day 1, 3 mg/kg on Day 2, and 1.5 mg/kg once weekly from Day 8 onward. RESULTS: Twelve patients (Cohort 1) and 2 patients (Cohort 2) were enrolled. Duration of emicizumab treatment was 8-639 days (median: 44.5 days) in Cohort 1 and 64 and 450 days in Cohort 2. In both cohorts, no major bleeds were observed after initial emicizumab administration. Six patients started their first rehabilitation sessions during emicizumab treatment and no rehabilitation-related bleeds occurred. Twenty-three surgeries were performed under emicizumab prophylaxis and there were no bleeds related to surgeries. Although asymptomatic deep vein thrombosis was reported in 1 patient in the primary analysis, no other thrombotic events occurred thereafter. Two patients developed anti-emicizumab antibodies, 1 of whom showed accelerated emicizumab clearance. Tailored IST approaches (delayed initiation, no use, or reduced dose) were successfully executed in 3 patients undergoing emicizumab prophylaxis. CONCLUSIONS: These results suggest that emicizumab prophylaxis has a favorable benefit-risk profile in PwAHA regardless of eligibility for IST.

Changes in Leptin to Adiponectin Ratio After Antiretroviral Therapy: A Pilot Observational Study.

AIM: Weight gain with the use of dolutegravir, bictegravir, and tenofovir alafenamide for antiretroviral therapy has been reported. However, studies on changes in body composition and the leptin/adiponectin ratio after antiretroviral therapy initiation are limited. These factors are important because they can be used as indicators of metabolic syndrome and cardiovascular disease risk. INTRODUCTION: This study aimed to investigate the changes in waist circumference, body composition, and adipokine levels after the initiation of antiretroviral therapy consisting of dolutegravir, bictegravir, and tenofovir alafenamide and evaluate the relationships between these parameters in Japanese patients living with human immunodeficiency virus. METHODS: This is a single-center, prospective, observational study. Waist circumference, body composition, and adipokine levels were measured at baseline and 12 months after antiretroviral therapy initiation in antiretroviral therapy-naive Japanese patients living with human immunodeficiency virus. Body composition was determined by bioelectrical impedance analysis. RESULTS: We included 11 patients (10 bictegravir/TAF/emtricitabine, 1 dolutegravir/lamivudine) in this study. The results showed no significant changes in waist circumference and body composition among the patients. The leptin/adiponectin ratio and serum leptin levels significantly increased after antiretroviral therapy initiation. Changes in waist circumference, fat mass, and visceral fat area showed a strong positive correlation. CONCLUSION: The leptin/adiponectin ratio increased following antiretroviral therapy initiation. The waist circumference measurement can be a simple, inexpensive, and useful method to identify changes in fat mass and visceral fat area after initiation of antiretroviral therapy.

Diagnostic and treatment guidelines for thrombotic thrombocytopenic purpura (TTP) in Japan 2023.

Thrombotic thrombocytopenic purpura (TTP) can rapidly become a life-threatening condition, and the importance of its appropriate diagnosis and treatment cannot be overstated. Until recently, TTP has mainly been diagnosed by clinical findings such as thrombocytopenia and hemolytic anemia. In addition to these clinical findings, however, reduced activity of a disintegrin-like and metalloprotease with thrombospondin type 1 motif 13 (ADAMTS13) below 10% has become internationally accepted as a diagnostic criterion for TTP. TTP is classified as immune-mediated TTP (iTTP) if the patient is positive for anti-ADAMTS13 autoantibodies, and as congenital TTP (cTTP) if ADAMTS13 gene abnormalities are detected. Fresh frozen plasma (FFP) transfusion is performed in patients with cTTP to supplement ADAMTS13. Plasma exchange therapy using FFP is conducted in patients with iTTP to supplement ADAMTS13 and to remove both anti-ADAMTS13 autoantibodies and unusually large von Willebrand factor (VWF) multimers. To suppress autoantibody production, corticosteroid therapy is administered in conjunction with plasma exchange. The monoclonal anti-CD-20 antibody rituximab is effective in patients with iTTP. In addition, caplacizumab, an anti-VWF A1 domain nanobody, has a novel mechanism of action, involving direct inhibition of platelet glycoprotein Ib-VWF binding. The recommended first-line treatments of iTTP in Japan are plasma exchange and corticosteroids, as well as caplacizumab.

A prospective, multicenter, open-label phase III study of emicizumab prophylaxis in patients with acquired hemophilia A.

BACKGROUND: Emicizumab is a bispecific antibody that mimics the cofactor function of activated factor (F) VIII. It prevents bleeds in patients with congenital hemophilia A regardless of the inhibitor status; however, no prospective clinical studies have been conducted for emicizumab in patients with acquired hemophilia A (PwAHA). OBJECTIVES: To describe the primary analysis results from a prospective, multicenter, open-label phase III study evaluating the efficacy, safety, and pharmacokinetics of emicizumab in PwAHA (AGEHA; JapicCTI-205151). METHODS: Emicizumab was administered subcutaneously at 6 mg/kg on day 1 and 3 mg/kg on day 2, followed by 1.5 mg/kg once weekly from day 8 onward. Predefined criteria for the completion of dosing included FVIII activity of >50 IU/dL. RESULTS: By the cutoff date (April 23, 2021), 12 patients on immunosuppressive therapy were enrolled, and 11 of them (91.7%) completed emicizumab treatment. The mean trough plasma emicizumab concentration rapidly reached a steady state (1 week), achieving the efficacious level that was established in patients with congenital hemophilia A (>30 µg/mL). Before first emicizumab administration, 7 patients (58.3%) experienced 77 major bleeds. During emicizumab treatment, no major bleeds occurred in any patient. Neither death due to bleeding or infection nor any study treatment-related serious adverse event was reported. One asymptomatic, nonserious deep vein thrombosis was discovered with no laboratory findings indicating any trend toward hypercoagulation. CONCLUSION: These results suggest that emicizumab prophylaxis with the tested dosing regimen and completion criteria may have a favorable benefit-risk profile in PwAHA.