Trial of stem-cell therapy in the womb to begin

Researchers have announced the first clinical trial of stem-cell therapy for fetuses still in the womb, as a treatment for brittle bone disease.

The trial team, led by the Karolinska Institutet in Stockholm, Sweden, has previously treated two children before birth with stem cells that target fractures in bones and help produce collagen.

'The oldest child to have received the treatment is now 13 and is performing better than expected and is still growing,' said Dr Cecilia Götherström, lead researcher on the trial. 'But we believe that we can improve the treatment for other patients by administering it to the unborn baby and again in repeated doses during the child's first years of life.'

Babies with Osteogenesis Imperfecta, which is caused by a mutation in the gene that produces collagen, are born with multiple fractures and are vulnerable to repeated bone fractures and growth problems throughout life. The disease can ultimately be fatal. Signs of the condition can be detected on antenatal ultrasound scans and it can be confirmed by genetic testing.

The trial, called BOOSTB4 ('Boost Brittle Bones Before Birth'), aims to involve 30 children with the condition; fifteen will be given the stem-cell treatment before birth and in the first few years of life and fifteen will be given the treatment only after birth. The number of fractures in both groups will be compared to determine whether in-utero stem-cell therapy is more effective than treatment after birth alone. The stem cells will be obtained from donated aborted fetuses.

Researchers have previously trialled the method in mice, with good results, but this is the first trial of its kind in humans. 'In preclinical mouse studies [the stem cells] honed to the site of bone fractures and improved the bone healing,' Dr Anna David, one of the collaborators from University College London, told BioNews.

Dr Dusko Ilic, a researcher from King's College London who is not involved in the trial, told BBC News that he welcomed the trial but cautioned that it could be difficult to interpret the results: 'How will we know whether a milder phenotype in a child that received the treatment is natural or is a result of the treatment?'

Dr David explained that the current trial will principally determine whether the treatment is safe. If it is then it would be followed by a full-scale randomised trial. If successful, the researchers hope it will lead the way to stem-cell therapies for other severe prenatal diseases, such as Duchenne muscular dystrophy or thalassaemia. 'This is a major step for fetal therapy for congenital disease,' she told BioNews.