A ‘miracle’ new gene therapy could effectively cure people with haemophilia, doctors claimed today.
Researchers say a one-off transfusion could stop people with the rare condition that prevents their blood from clotting having to take weekly injections to manage it.
The Phase 1-2 trial of 10 patients with haemophilia B found nine no longer had to take jabs to replace clotting agents more than two years after having the treatment, known as FLT180a.
Lead author Professor Pratima Chowdary, a haematologist at University College London, said curing the condition ‘will be a reality for the majority of the adults in the next one to three years’.
Gene therapies have already been shown to hold promise with treating haemophilia A patients, who make up 85 per cent of those with the condition.
But this new treatment is one of the first to be trialled for people with haemohilia B, which is caused by a missing protein called a clotting factor.
None are yet available on the NHS and there have been concerns about price, with a haemopilia A treatment that displayed similar results earlier this month estimated to cost between £1.5million and £2.5million per dose.
Current clotting factor injections can cost between £150,000 to £200,000 per year.
A new gene therapy has dramatically cut the risk of bleeding in people with the rare condition haemophilia B, experts have said (David Davies/PA)
WHAT IS THE DIFFERENCE BETWEEN HAEMOPHILIA A AND HAMEOPHLIA B?
Haemophilia is a rare condition that affects the blood’s ability to clot. It’s usually inherited, and most people who have it are male.
Normally, when you cut yourself, substances in the blood known as clotting factors combine with blood cells called platelets to make the blood sticky. This makes the bleeding stop eventually.
People with haemophilia don’t have as many clotting factors as there should be in the blood. This means they bleed for longer than usual.
There are two types of haemophilia: haemophilia A, which makes up 85 per cent of cases, and the less common haemophilia B.
Hameophilia B is caused by a deficiency of clotting factor IX, while haemophilia A patients are missing factor VIII.
There’s no cure for haemophilia, but treatment usually allows a person with the condition to enjoy a good quality of life.
Genetically engineered clotting factor medicines are used to prevent and treat prolonged bleeding. These medicines are given as an injection.
Around 6,000 people in Britain have haemophilia, while there are 20,000 in the US with the condition.
It is usually inherited and mostly affects men, because the missing protein is on the X chromosome.
Normally, when a person cuts themselves, clotting factors mix with blood cells called platelets to make the bleeding stop.
But people with haemophilia are lacking clotting factors and are at risk of heavy bleeding. This can be deadly and also causes severe joint pain in some sufferers.
Professor Chowdary, who also works at Royal Free Hospital in London, told the BBC: ‘We have a lot of young patients in excruciating agony and there’s nothing we can do to reverse the joint damage.’
The study, published in the New England Journal of Medicine, was led by experts from UCL, the Royal Free Hospital and biotech company Freeline Therapeutics.
The ten patients chosen for the study all had ‘severe or moderately severe’ haemophilia B — the rarer form of the condition that makes up 15 per cent of cases.
It is caused by a deficiency of clotting factor IX, while haemophilia A patients are missing factor VIII.
They were given one of four different doses of the therapy at the start of the study and doctors measured their factor IX levels at the end to see how it affected their long-term condition.
After an average of 27 months, five patients had normal factor IX levels (from 51 to 78 per cent), three patients had levels from 23 to 43 per cent, and one had a level of 260 per cent.
Nine patients no longer had to take weekly injections. Professor Chowdary said: ‘We’re very excited by the results.
‘Removing the need for haemophilia patients to regularly inject themselves with the missing protein is an important step in improving their quality of life.
‘The long-term follow up study will monitor the patients for durability of expression and surveillance for late effects.’
FLT180a works by using a small part of a virus to deliver a copy of a gene directly to patient tissues to compensate for one that is missing.
This new gene can then generate the missing FIX proteins which allows the blood to clot as normal.
Patients on the trial had to take immune suppressing drugs over several weeks to several months, to prevent their immune systems from rejecting the therapy.
While the treatment was generally well tolerated, all patients experienced some form of side-effects, with an abnormal blood clot in one who received the highest FLT180a dose and had the highest levels of the protein.
Freeline co-founder Professor Amit Nathwani, a haematologistat UCL, who co-authored the study, said: ‘Gene therapy is still a young field that pushes the boundaries of science for people with severe genetic diseases.’
He said the new trial adds to ‘the growing body of evidence that gene therapy has the potential to free patients from the challenges of having to adhere to lifelong therapy or could provide treatment where none exists today.’