Haemophilia treatment: Successful long road to being ‘functionally cured’

Forty years after their members were infected by blood products provided by the State, the haemophilia community in Ireland is making news again for altogether better reasons.

That scandal saw hundreds of people with the condition contract the HIV and hepatitis C viruses from contaminated anti-clotting products they were administered. More than 100 died.

Now, the community is celebrating the success of the first gene therapy to provide an “effective cure” for the condition.

Ironically, the treatment uses another virus to deliver the therapy intravenously to the liver of the haemophilia B patient, where it provides a new “working copy” of the genes for clotting factor protein.

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In another irony, one of the three Irish patients who took part in a worldwide trial to test the gene therapy is Brian O'Mahony, long-time head of the Irish Haemophilia Society.

For years, O’Mahony has needed regular intravenous injections to ensure his blood clots; twice a week until recently, when a new product pushed out the time interval to a week to 10 days.

“Often there’d be no cause for a bleed; I could be just sitting at a desk and it could happen, spontaneously. With the injections, you’d suffer peaks and troughs, as your levels went up and then down again and you needed a fresh jab.”

Nine months into the trial, he describes himself as “functionally cured”. “It has worked very well. I haven’t had a single bleeding episode since February and I haven’t had an injection since then.”

Dr Niamh O’Connell from the National Coagulation Centre in St James’s Hospital says the problem with current treatments is that they require intravenous injection and their effects start wearing off immediately. In contrast, gene therapy provides a constant and lasting level of protection.

The potential of gene therapy for curing the condition has taken 20 years to be realised, she says.

The trial uses so-called adeno-associated virus (AAV) to get the gene into the body. AAV are small viruses that are not currently known to cause disease but can cause a very mild immune response.

Severity levels

There are 860 people with haemophilia in Ireland, 60 of whom have a deficiency in factor IX (haemophilia B).

The severity of haemophilia is categorised according to the percentage of blood clotting factor the person can produce. Severe cases produce less than 1 per cent of the normal level, moderate cases between 2 and 5 per cent and mild cases anywhere between 5 and 40 per cent.

In the trial, factor IX levels in patients rose from under 2 per cent to an average of over 37 per cent after six weeks. Most reported no bleeding.

Although patients on the trial are functionally cured they can still pass on the genetic condition to their children, Dr O’Connell points out.

Referring to the “horrendous events” of the 1980s and 1990s, when people with haemophilia were infected with contaminated blood products, she says the new therapy shows “good things can come from tragedies” with services better-organised as a result of what had happened.

“This could not have been achieved without our partnership with the patient community, the clinical research facilities which have been developed at St James’s and the support of the hospital over 50 years.”

“It’s been a long journey,” O’Mahony says of his work for the community since the tragedies of the 1980s. “If you’d told me 38 years ago I’d still be here, I don’t think I would have believed it.”