Fidanacogene Elaparvovec for Hemophilia B — A Multiyear Follow-up Study
Bibliographic record
Abstract
BACKGROUND: Treatment with fidanacogene elaparvovec, a recombinant adeno-associated virus (AAV) vector developed for the treatment of hemophilia B, led to sustained expression of the high-activity factor IX variant (FIX-R338L, or FIX-Padua) in a phase 1-2a study. The long-term safety and efficacy of this treatment are not known. METHODS: vector genomes (vg) per kilogram of body weight; thereafter, participants could enroll in a 5-year follow-up study. Safety end points included adverse events and changes in laboratory measures. Efficacy end points included the annualized rate of treated bleeding events (annualized bleeding rate) and factor IX activity. RESULTS: A total of 14 participants provided consent and completed at least 3 years of follow-up (median, 5.5; range 3 to 6); participation was ongoing among 8 at the data cutoff. None of the participants reported treatment-related adverse events after year 1. Throughout follow-up, nine serious adverse events were noted in 4 participants; none were thrombotic or treatment-related. No factor IX inhibitors were detected. Throughout follow-up, mean factor IX activity was in the mild hemophilia range; the mean annualized bleeding rate was less than 1, and 10 participants had no treated bleeding episodes. Surveillance liver ultrasounds obtained from year 1 onward showed no evidence of cancer but showed steatosis in 4 participants who had weight gain and elevated aminotransferase levels (maximum alanine aminotransferase level, 77 U per liter). One participant with a history of hepatitis C, hepatitis B, human immunodeficiency virus infection, and an elevated body-mass index had progression of underlying advanced liver fibrosis. A total of 13 surgical procedures were performed in 8 participants; exogenous factor IX was administered for 10 procedures, and no associated unexpected bleeding complications occurred. CONCLUSIONS: vg per kilogram, one of the lowest intravenous doses of AAV used for any indication. (Funded by Pfizer; ClinicalTrials.gov number, NCT03307980.).
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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 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
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".