The treatment, called Kymriah (tisagenlecleucel), is also the first gene therapy to be approved in the USA by the Food and Drug Administration (FDA).
'We're entering a new frontier in medical innovation with the ability to reprogram a patient's own cells to attack a deadly cancer,' said FDA commissioner Dr Scott Gottlieb. 'New technologies such as gene and cell therapies hold out the potential to transform medicine and create an inflection point in our ability to treat and even cure many intractable illnesses.'
The drug is a treatment for acute lymphoblastic leukaemia (ALL), a type of cancer which causes the bone marrow to produce abnormal B or T lymphocytes (white blood cells). The National Cancer Institute estimates that approximately 3,100 patients aged 20 and younger are diagnosed with ALL each year.
Produced by Novartis, Kymriah is made from the patient's own T lymphocytes, which are filtered from the patient's blood and then genetically modified to include a gene coding for a protein called chimeric antigen receptor (CAR). The so-called CAR-T cells are then injected back in the patient, where they are able to recognise and destroy leukaemic B cells.
Kymriah has an advantage over traditional chemotherapy as it does not attack the patient's healthy cells and weaken the body's natural defences. Clinical trials with 63 paediatric and young adult patients with relapsed ALL showed an 83 percent overall remission rate within three months of treatment.
Subsequently, the FDA has approved Kymriah for ALL patients over 25 who have relapsed or have not responded to other treatments.
'Not only does Kymriah provide [patients] with a new treatment option where very limited options existed, but a treatment option that has shown promising remission and survival rates in clinical trials,' said Dr Peter Marks, director of the FDA's Centre for Biologics Evaluation and Research.
However the drug does have potentially life-threatening side effects, including inflammation and destruction of normal B cells which leaves patients prone to infections. The FDA requires hospitals that dispense Kymriah be specially certified to treat such side effects.
Although delivered as a one-time dose, Kymriah is priced at US $475,000. Dr Craig Devoe of Northwell Health Cancer Institute, New York, told AFP that he did not think the price was reasonable, and questioned how long treatment would be effective. 'Not just responding but staying in response long term is what patients want,' he said. 'We really don't know how long these cells are going to stay active.'
An application with the European Medicines Agency is expected to be filed by the end of the year, and the FDA may also approve Kymriah to treat lymphoma.