A groundbreaking gene therapy that treats cancer patients by manipulating their immune system has "cured" more than a third of patients, scientists claim.
After being given the treatment, 36 per cent of advanced blood cancer patients showed no sign of the disease, the Daily Mail reports.
Slightly more than half were still alive nine months on, despite sufferers only being expected to live for six months before succumbing to the disease.
And 82 percent of the patients had their cancer shrink by at least half at some point in the study, the researchers found.
Dubbed a "living drug" by experts, the treatment, called CAR-T therapy, removes key fighting cells called T-cells from the immune system.
Scientists then insert a gene that directly targets cancer into them, before giving them back to the patient through a drip.
Despite cancerous cells being well-equipped to evade detection from the immune system, the treatment helps the body battle the disease.
"The numbers are fantastic," said Dr Fred Locke, a blood cancer expert at Moffitt Cancer Center in Tampa who co-led the study.
"These are heavily treated patients who have no other options."
Kite Pharma, a US-based pharmaceutical company, released the results from the first six months of its trial. However, the findings have yet to be reviewed by other experts.
Patients in the study had one of three types of non-Hodgkin lymphoma, a blood cancer, and had failed all other treatments.
Dimas Padilla, 43, was one of the 101 patients who underwent the experimental treatment.
He was told his cancer was slowly worsening, chemotherapy was no longer working and there was no match to enable a second try at a stem cell transplant.
But after undergoing the CAR-T therapy in August, he saw his tumours ''shrink like ice cubes'' and is now in complete remission.
"They were able to save my life," he said.
However, there are still concerns that the treatment has significant side effects and could even be deadly.
During the trial, two people died from the therapy, not their cancer, after their immune systems were placed into a state of overdrive.
Thirteen per cent developed a dangerous condition where the immune system over-reacts in fighting the cancer.
Roughly a third of patients developed anaemia or other blood-related issues, according to the researchers.
Nearly one-third also reported neurological problems such as sleepiness, confusion, tremor or difficulty speaking, but these typically lasted just a few days.
Full results will be presented at the American Association for Cancer Research conference in April and the company plans to seek approval from European regulators later this year.
Company officials would not say what the treatment might cost, but other types of immune system therapies have been very expensive.