Gene therapy breakthrough for haemophilia

Today researchers at Royal Prince Alfred Hospital in Sydney and their international collaborators announced a breakthrough in gene therapy for haemophilia B.

Gene therapy press conference group
Mark Lee and family, Prof John Rasko and Daniel Credazzi at the press conference today

In a study of 10 men with haemophilia B who were treated with a single injection of gene therapy, all had a substantial increase in their clotting factor IX (9) levels. As a result of this treatment nearly all had no further bleeding episodes. 8 out of 10 have not used clotting factor replacement therapy since then.

For RPA’s Professor John Rasko and the research team from Children’s Hospital in Philadelphia, this is the culmination of 20 years’ work.

“We are very excited about the results, as those people in our trial have previously had to live with the risks of spontaneous bleeding every day. To prevent potentially life-threatening bleeds they have typically had to inject themselves with clotting factors every few days,” said Professor Rasko. “This trial has targeted haemophilia B, which affects about 500 males in Australia – with about 100 experiencing a severe form of the condition, but our next focus is targeting haemophilia A, which affects more than 2300 people.”

Before receiving the experimental gene therapy treatment, clinical trial participant Mark Lee, 38, had severe haemophilia and clotting factor infusions up to three times a week since birth. Since the gene therapy injection his factor levels are in the normal range and he has not had any bleeds.

 “This is life-changing for me. I spent my childhood wrapped up in cotton wool, unable to play football or do any of the things my mates could. I would always remind myself that there were people worse off than me, but it was still disappointing,” said Mark Lee. “I have two daughters who are carriers for haemophilia, but now I know that if they have affected children, it will be one injection and they can live normal lives. This goes beyond our little family currently. It will have a positive impact on all generations to come.”

Daniel Credazzi, Vice-President of Haemophilia Foundation Australia, who has a son with haemophilia, welcomed the breakthrough, saying: “The real potential of a cure with safe and effective gene therapy is very exciting for people living with this chronic condition, and for their families. My wife and I have been looking forward to this news since our son was diagnosed with haemophilia 13 years ago. We are grateful to all the courageous people who have participated in gene therapy trials.” 


Although this was a small study and has not yet had long-term follow-up, Professor Rasko sees this as a major step in haemophilia treatment. “We now know how to beat the immune response to achieve what may be a permanent cure,” he said.

Before the study started, all 10 participants had very low factor levels, below 2%. After treatment their factor levels were sustained at a mean of approximately 30%. Only one participant needed to use factor replacement therapy for bleeds after treatment, but used 91% less factor than before. There were no serious side effects.

The results of the clinical trial were published in today’s New England Journal of Medicine


Professor Rasko explained that the success of this small clinical trial can now pave the way for a larger study in haemophilia B with long-term monitoring for at least 15 years to confirm the results. His team at RPA and their collaborators in Philadelphia will also be commencing a similar small experimental clinical trial in haemophilia A in 2018. This forms part of the international work currently underway to investigate gene therapies for haemophilia that are safe and effective.

For people with haemophilia in Australia, these are exciting times, with a range of new ground-breaking haemophilia treatments coming on to the market as well as the first indications of success in these experimental gene therapy treatments. If you have haemophilia and are interested in more information about experimental gene therapy, talk to your Haemophilia Treatment Centre.

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