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New Data From uniQure's Gene Therapy for Hemophilia B is Impressive

JUNE 11, 2016
James Radke, PhD
At the 21st Congress of the European Hematology Association (EHA) in Copenhagen, Denmark this weekend, data from a phase 1/2  trial looking at the safety and efficacy of uniQure’s gene therapy in patients with hemophilia B was presented. The study involving 5 people with severe or moderately severe hemophilia B found that 4 of the patients were able to be free of any prophylactic infusions 6 months after receiving the gene therapy.

Hemophilia B

Hemophilia B is a genetic disorder caused by missing or defective factor IX, a clotting protein. Although it is passed down from parents to children, about 1/3 of cases are caused by a spontaneous mutation, a change in a gene.2
 
Current standard of care for patients with hemophilia B involves chronic replacement of FIX protein through intravenous infusion. In 2013, the World Federation of Hemophilia estimated there were more than 28,000 hemophilia B patients worldwide, including 4,000 patients in the United States.
 
Numerous gene therapies are in development for hemophilia B, including ones being developed Baxalta, BioMarin, Biogen, Dimension Therapeutics, Spark Therapeutics, and many more.

Phase 1/2 Study

Five patients received a single administration of AMT-060 gene therapy, at the initial low dose of 5x1012 gc/kg. The AMT-060 gene therapy consists of a codon-optimized wild type FIX gene cassette, the LP1 liver promoter and an AAV5 viral vector. All patients were receiving rFIX prophylaxis weekly or twice-weekly prior to treatment.
 
As of 6 months following gene therapy, all patients saw improvements in their disease phenotype and achieved sustained increases in FIX activity (see table).
 
      
                 Pre Gene Therapy                             Post Gene Therapy
 Patient 
age
FIX
Activity
Hemophilia
severity
Prophy-
laxis
FIX
Activity
Hemophilia
severity
Prophy-
laxis

34

< 1%

Severe

Yes

6.3%

Mild

No
54 < 1% Severe Yes 5.4% Mild No
72 < 1% Severe Yes < 2% Moderate Yes
71 < 1% Severe Yes 2.9% Moderate No
69 1.5% Mod-severe Yes 6.2% Mild No

Prior the therapy, all 5 patients required chronic, prophylactic (precautionary) infusions of Factor IX concentrate to manage bleeding. After treatment with AMT-060, total usage of Factor IX concentrate declined substantially, with four patients remaining free of any prophylactic infusions through the April 26, 2016 cut-off date.
 
Dr. Frank Leebeek, Professor of Hematology at Erasmus University Medical Center in Rotterdam said in a press release, "After six months of follow-up, I can say as a clinician who regularly treats hemophilia patients that the impact on the quality of life for these patients treated with AMT-060 is very positive." Dr Leebeek added, "The increases in FIX activity and the overall stability of the activity observed over a 6-month period are cause for optimism, as they are associated with meaningful clinical benefits as well as reduced need for ongoing infusions of recombinant FIX therapy."

Safety

One patient experienced a mild, transient and asymptomatic elevation of alanine aminotransferase (ALT) 10 weeks after treatment. No cellular immune response was evident. None of the five patients developed inhibitory antibodies against FIX.

Looking Ahead

A second cohort of 5 patients have been given a higher dose of AMT-060 (2x1013 gc/kg). Data from those patients is expected by the end of the year.

Conference Call Monday Morning

uniQure will discuss the data in a webcast conference call at 8:00 am EST on Monday, June 13, 2016. For more information on the webcast, click here.

Reference

Leebeek FWG, Schwaeble J, Meijer K, et al. First results from a dose-escalating study with AAV5 vector containing wild type human factor IX gene therapy in patients with severe of moderately-severe haemophilia B. poster presented at 21st Congress of the European Hematology Association; Copenhagen, Denmark; June 9-12, 2016. Abstract S467.



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