Hemophilia B Gene Therapy with a High-Specific-Activity Factor IX Variant.
N Engl J Med
; 377(23): 2215-2227, 2017 12 07.
Article
em En
| MEDLINE
| ID: mdl-29211678
ABSTRACT
BACKGROUND:
The prevention of bleeding with adequately sustained levels of clotting factor, after a single therapeutic intervention and without the need for further medical intervention, represents an important goal in the treatment of hemophilia.METHODS:
We infused a single-stranded adeno-associated viral (AAV) vector consisting of a bioengineered capsid, liver-specific promoter and factor IX Padua (factor IX-R338L) transgene at a dose of 5×1011 vector genomes per kilogram of body weight in 10 men with hemophilia B who had factor IX coagulant activity of 2% or less of the normal value. Laboratory values, bleeding frequency, and consumption of factor IX concentrate were prospectively evaluated after vector infusion and were compared with baseline values.RESULTS:
No serious adverse events occurred during or after vector infusion. Vector-derived factor IX coagulant activity was sustained in all the participants, with a mean (±SD) steady-state factor IX coagulant activity of 33.7±18.5% (range, 14 to 81). On cumulative follow-up of 492 weeks among all the participants (range of follow-up in individual participants, 28 to 78 weeks), the annualized bleeding rate was significantly reduced (mean rate, 11.1 events per year [range, 0 to 48] before vector administration vs. 0.4 events per year [range, 0 to 4] after administration; P=0.02), as was factor use (mean dose, 2908 IU per kilogram [range, 0 to 8090] before vector administration vs. 49.3 IU per kilogram [range, 0 to 376] after administration; P=0.004). A total of 8 of 10 participants did not use factor, and 9 of 10 did not have bleeds after vector administration. An asymptomatic increase in liver-enzyme levels developed in 2 participants and resolved with short-term prednisone treatment. One participant, who had substantial, advanced arthropathy at baseline, administered factor for bleeding but overall used 91% less factor than before vector infusion.CONCLUSIONS:
We found sustained therapeutic expression of factor IX coagulant activity after gene transfer in 10 participants with hemophilia who received the same vector dose. Transgene-derived factor IX coagulant activity enabled the termination of baseline prophylaxis and the near elimination of bleeding and factor use. (Funded by Spark Therapeutics and Pfizer; ClinicalTrials.gov number, NCT02484092 .).
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Fator IX
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Terapia Genética
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Hemofilia B
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Transgenes
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Vetores Genéticos
Tipo de estudo:
Clinical_trials
Limite:
Adolescent
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Adult
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Humans
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Male
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Middle aged
Idioma:
En
Ano de publicação:
2017
Tipo de documento:
Article