ArticleBlood advances2023
Differences in wild-type- and R338L-tenase complex formation are at the root of R338L-factor IX assay discrepancies.
Article in Blood advances, 2023. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 7 papers.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
7 citing papers in PubMed, 14 citations in OpenAlex.
- Field Study and Correlative Studies of Factor IX Variant FIX-R338L in Participants Treated with Fidanacogene Elaparvovec.Thrombosis and haemostasis · 2024Trial
- Laboratory Challenges in the Era of Novel Haemophilia Therapies.Transfusion medicine and hemotherapy : offizielles Organ der Deutschen Gesellschaft fur Transfusionsmedizin und Immunhamatologie · 2026Review
- Nine areas with outstanding challenges for hemophilia B research.Therapeutic advances in hematology · 2026Review
- Evaluation of One-Stage Assays for the Monitoring of Recombinant Human Factor IX Padua Activity After Etranacogene Dezaparvovec Gene Therapy.Haemophilia : the official journal of the World Federation of Hemophilia · 2025Article
- UKHCDO gene therapy taskforce: Guidance for implementation of haemophilia gene therapy into routine clinical practice for adults.Haemophilia : the official journal of the World Federation of Hemophilia · 2025Article
- CRISPR-Mediated In Situ Introduction or Integration ofInternational journal of molecular sciences · 2023Article
- Gene therapy for hemophilia: looking beyond factor expression.Experimental biology and medicine (Maywood, N.J.) · 2022Review
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
13 authors at 3 institutions in 1 country.
Funding
No grant is acknowledged in the PubMed record.
Abstract
Adeno-associated virus (AAV) gene therapy has the potential to functionally cure hemophilia B by restoring factor (F)IX concentrations into the normal range. Next-generation AAV therapies express a naturally occurring gain-of-function FIX variant, FIX-Padua (R338L-FIX), that increases FIX activity (FIX:C) by approximately eightfold compared with wild-type FIX (FIX-WT). Previous studies have shown that R338L-FIX activity varies dramatically across different clinical FIX:C assays, which complicates the monitoring and management of patients. To better understand mechanisms that contribute to R338L-FIX assay discrepancies, we characterized the performance of R338L-FIX in 13 1-stage clotting assays (OSAs) and 2 chromogenic substrate assays (CSAs) in a global field study. This study produced the largest R338L-FIX assay dataset to date and confirmed that clinical FIX:C assay results vary over threefold. Both phospholipid and activating reagents play a role in OSA discrepancies. CSA generated the most divergent FIX:C results. Manipulation of FIX:C CSA kits demonstrated that specific activity gains for R338L-FIX were most profound at lower FIX:C concentrations and that these effects were enhanced during the early phases of FXa generation. Supplementing FX into CSA had the effect of dampening FIX-WT activity relative to R338L-FIX activity, suggesting that FX impairs WT tenase formation to a greater extent than R338L-FIX tenase. Our data describe the scale of R338L-FIX assay discrepancies and provide insights into the causative mechanisms that will help establish best practices for the measurement of R338L-FIX activity in patients after gene therapy.
Indexed as
Identifiers
What OpenQuestion holds
Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.