Although thalassemia can cut short life expectancy, with regular blood transfusions – combined with iron-chelating drugs, which prevent an iron overload from these transfusions – many patients live long lives, with several of Dr Kittiphong’s patients in their late 70s.
Thalassemia can be cured through a stem cell transplant. But although many Thai hospitals can perform this procedure, it is only offered for severe cases of beta-thalassemia, and even then rarely, because of the risks involved – Dr Kittiphong says that there is a two per cent risk your body will reject the transplant, leading to death.
A company called Bluebird Bio has also developed a gene therapy for people with beta-thalassemia. But this is a challenging process – thalassemia can be caused by one of hundreds of mutations; the specific faulty gene needs to be identified before it can be corrected. It also costs 30 to 40 million baht – between £680,000 and £910,000 – making it prohibitively expensive in most of southeast Asia, says Dr Kittiphong.
There are clinical trials ongoing for newer gene editing tools – in the UK, there was excitement in August when it was announced that the first of these to use Crispr-technology would be available to beta-thalassemia patients through the NHS. It comes after Britain became the first country in the world to authorise Crispr therapy for use in patients last November.
Called Casgevy and developed by the company Vertex, this process does not target specific gene mutations in stem cells, but tells the body to stop producing adult haemoglobin and start producing fetal haemoglobin. This is what our bodies use when in the womb, but the genetic switch is flipped once we’re born.
But because beta-thalassemia only affects adult haemoglobin, disabling this switch cures the disorder. In international clinical trials, 93 per cent of patients with beta thalassaemia did not need a blood transfusion for at least a year after having the treatment.
“I think this is a better approach because it is universal,” says Dr Kittiphong. “But these sorts of cures are only available in Thailand through clinical trials.”
