Gene therapy developed for babes with severe combined immunodeficiency may have successfully "cured" all of those who received treatment, doctors claimed last night.
Eight infants now have fully functioning immune systems and are living normal lives, US researchers reported in the New England Journal of Medicine.
Not one of the children has developed a life-threatening infection since the treatment and normal numbers of multiple types of immune cell developed within four months of gene therapy in seven cases, the researchers report.
The doctor who led the project, Dr Brian Sorrentino, St. Jude Children’s Research Hospital, Tennessee, USA, died after compiling the latest findings and submitting them for publication late last year.
His colleague Dr Ewelina Mamcarz said: "These patients are toddlers now, who are responding to vaccinations and have immune systems to make all immune cells they need for protection from infections as they explore the world and live normal lives.
"This is a first for patients with SCID-X1."
The treatment involved inserting a correct copy of the IL2RG gene into the genome of patient blood stem cells. The cells were frozen and tested before being returned to the patients.
Before undergoing the autologous stem cell transplant, the babies received two days of low-dose busulfan to make space for the treated cells. One patient needed a second dose of therapy.
The viral vector has "insulators" included to prevent activation of neighbouring genes and reduce the risk of triggering leukaemia.
The doctors said they expected most patients to experience "a complete durable immune response without side effects."
Dr Anthony Fauci, director of the US National Institute of Allergy and Infectious Diseases, said: "These exciting new results suggest that gene therapy may be an effective treatment option for infants with this extremely serious condition, particularly those who lack an optimal donor for stem cell transplant.
"This advance offers them the hope of developing a wholly functional immune system and the chance to live a full, healthy life."
NEJM 18 April 2019
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