Experience with Emicizumab Among People with Hemophilia A in the Canadian Hemophilia Bleeding Disorders Registry
Bibliographic record
Abstract
Background: The use of emicizumab as prophylaxis to prevent bleeding or reduce the frequency of bleeding episodes in congenital hemophilia A (HA) was approved by Health Canada for the treatment of people living with HA (PwHA) with FVIII inhibitors in 2018, and without inhibitors in 2019. Here we present the results of a non-interventional, cohort study, using data routinely collected by the Canadian Bleeding Disorders Registry (CBDR) to evaluate treatment patterns of emicizumab in Canada and the associated safety and effectiveness outcomes, including quality of life. Methods: De-identified data were extracted from the CBDR database for all registered PwHA who had received emicizumab at least once prior to December 31, 2022. Baseline demographic characteristics were stratified by disease severity (defined by the level of endogenous FVIII activity) and age. Effectiveness outcomes were measured by the proportion of patients with zero, traumatic, spontaneous, or joint bleeds as well as annualized bleeding rates (ABR) for any treated bleed. Intra-patient comparisons of bleeding were performed for all patients and for those with at least six months follow-up in both pre- and post-emicizumab periods as a sensitivity analysis. Effectiveness outcomes also included patients' Hemophilia Joint Health Score (HJHS), Patient Reported Outcomes, Burdens and Experiences (PROBE), and EQ-5D index and visual analog scale (VAS) scores. We performed a complete data analysis, without imputation. This study was approved by the research ethics board of McMaster University and other participating centers, and abides by the guiding principles of the Declaration of Helsinki. Results: In total, 533 PwHA received at least one dose of emicizumab (PwHA E) in the CBDR database. Overall, 498 (93.4%) PwHA E had severe disease, 28 (5.3%) had moderate disease, and 7 (1.3%) had mild disease. At start of emicizumab exposure, 220 (41.3%) PwHA E were <18 years old; 78 (14.6%) PwHA E had current FVIII inhibitors, 82 (15.4%) had a history of FVIII inhibitors, and 373 (70%) had no history of inhibitors ( Table 1). A total of 13 adverse events were reported in the entire observation period, including one event of thrombosis (occurring in one person with COVID-19), seven allergic reactions, two FVIII Inhibitor development, two neurological events (headache; and headache, nausea, and vomiting) and one case of large hematoma developed at operative site following removal of port-a-cath. Moreover, nine COVID-19 cases were reported as adverse events. Over a median (first quartile, third quartile) follow-up time of 249 (136, 395) days, 388 (72.8%) PwHA E had no recorded bleeds. Out of 145 PwHA E with recorded bleeds, 106 had joint bleeds, 87 had traumatic bleeds, 69 had spontaneous bleeds and 46 had other bleeds (Table 2). An intra-patient comparison in all PwHA E (n=533) showed a decrease in mean (95% confidence interval [CI]) annualized bleeding rate (ABR) from 1.22 (1.06, 1.42), pre-emicizumab (2018, prior to first dose) to 0.50 (0.41, 0.60) post-emicizumab (rate ratio (95% CI) 0.41 (0.33, 0.50), p-value <0.001). The Intra-patient comparison in PwHA E without current inhibitor (n=455) showed a decrease in mean ABR (95% CI) from 1.02 (0.87, 1.19) to 0.54 (0.44, 0.66) (rate ratio (95% CI) 0.53 (0.43, 0.65), p-value <0.001). The Intra-patient comparison in PwHA E with current inhibitor (n=78) showed a decrease in mean ABR (95% CI) from 5.03 (3.30, 7.66) to 0.41 (0.26, 0.65) (rate ratio (95% CI) 0.08 (0.04, 0.15), p-value <0.001). Conclusions: This analysis describes the baseline characteristics, safety and effectiveness outcomes of Canadian PwHA treated with emicizumab before December 31, 2022. A total of 387 new patients were included in this analysis compared to the previous one (data cut: December 31, 2021, n=146). The data shows that 72.8% PwHA E had no recorded bleeds since they started emicizumab and that there was a substantial decrease in bleeds post-emicizumab in both PwHA with and without current FVIII inhibitor. The safety profile of emicizumab was consistent with previous reports. The CBDR allows for a longitudinal follow-up of the Canadian hemophilia A population, which can inform healthcare practitioners and regulatory authorities of the safety and efficacy outcomes of treatments in routine clinical practice.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.002 | 0.008 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.003 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".