The trial used genetically modified cells taken from the patient's own immune system, known as CAR-T therapy. After six months, cancer had shrunk by at least half in 82 percent of patients with non-Hodgkin lymphoma.
'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.'
The treatment, developed by US pharmaceutical company Kite Pharma, involves filtering immune T cells from the patient's blood to make a 'living drug'. The T cells are modified using a gene which enables them to better identify tumour cells. After being multiplied in the lab, the cells are injected back into the patient, where they continue to multiply and enable the patient's immune system to find and destroy the cancer cells.
The therapy was tested in 101 patients with one of three types of non-Hodgkin lymphoma for which other treatments had been unsuccessful. Six months after a single treatment, 36 percent of patients were in complete remission and tumours had shrunk by at least half in 41 percent of patients.
'This seems extraordinary... extremely encouraging,' said Dr Roy Herbst, cancer medicines chief at the Yale Cancer Center, who was not involved in the study. Dr Herbst said that follow-up beyond six months is still needed to see if the benefit wanes, but added, 'this certainly is something I would want to have available.'
Two patients died from the treatment, although this is fewer than has been seen in other tests of CAR-T therapy. Thirteen percent developed a dangerous immune system overreaction, 28 percent of patients developed temporary neurological problems, and about a third developed treatable anaemia or other blood-count related problems.
Median survival for such patients had been about six months, but after nine months more than half of the trial patients are still alive. The full results of the trial will be presented at the American Association for Cancer Research conference in April.
Kite Pharma plans to seek approval of the treatment from the FDA by the end of March, and in Europe later this year.
Martin Ledwick, Cancer Research UK's head cancer information nurse, said: 'These results are promising and suggest that one day CAR-T cells could become a treatment option for some patients with certain types of lymphoma. But, we need to know more about the side effects of the treatment and long-term benefits.'