Table 2.
Summary of factor IX activity, administered doses, and treatment response for gene therapies with published results.
| Therapy and Sponsor | Factor IX Activity | Doses, vg/kg | Patients Responded to Therapy | Reference |
|---|---|---|---|---|
| AMT-060, UniQure | 7.0–7.4% at 4 years | 5 × 1012, 2 × 1013 | 10/10 | [24] |
| AMT-061/Etranacogene dezaparvovec, UniQure | 34.3% ± 4.8% at 18 months | 2 × 1013 | 52/54 | [19] |
| SPK-9001/PF-06838435/Fidanacogene elaparvovec, Spark Therapeutics, Pfizer | 22.9% ± 9.9% at 5 years | 5 × 1011 | 15/15 | [25] |
| FLT180a/Verbrinacogene setparvovec, Freeline Therapeutics | 51–78% in 5 patients, 23–43% in 3 patients, 1 patient with 260% | 3.84 × 1011; 6.4 × 1011; 8.32 × 1011; 1.28 × 1012 | 9/10, 1 participant continued prophylaxis | [21] |
| BBM-H901, Institute of Hematology and Blood Diseases Hospital, China | 36.9% ± 20.5% at 58 weeks | 5 × 1012 | 10/10 | [23] |
| DTX101, Ultragenyx Pharmaceutical Inc (previously Dimension Therapeutics) | 5–20% at 8–14 weeks but loss of FIX levels at 32 weeks in all patients except one with ~20% activity | 1.6 × 1012; 5.0 × 1012 | 6/6 | [26] |
| AskBio009/BAX 335, Baxalta (Shire), Takeda | 2.8–58.5% in different dose cohorts at 11 weeks | 2 × 1011; 1 × 1012; 3 × 101 | 7/8 had measurable factor IX activity up to 11 weeks; only 1/7 had 20% expression for 4 years |
[22] |
| scAAV2/8-LP1-hFIXco, St. Jude Children’s Research Hospital | 1–6% at 3.2 years; 5.1 ± 1.7% in a high-dose cohort | 2 × 1011; 6 × 1011, 2 × 1012 | 6/10, 90% reduction of bleeding episodes and in factor IX prophylaxis use in high-dose cohort | [27,28] |
| AAV2-FIX, Avigen | Transient at a maximum level of 1.6% | 2 × 1011 to 1.8 × 1012 | All 8 participants with a severe form had only local factor IX expression in muscles | [20] |