'This trial is primarily concerned with three questions: can we edit T cells in this specific way? Are the resulting T cells functional? And are these cells safe to infuse into a patient? This early data suggests that the answer to all three questions may be yes,' said study leader, Dr Edward Stadtmauer at the University of Pennsylvania in Philadelphia.
The therapy was tested in two patients with multiple myeloma (a blood cancer) and one with sarcoma. The team used CRISPR/Cas9 to delete three genes and insert one gene into the patients' T cells.
'Our use of CRISPR editing is geared toward improving the effectiveness of gene therapies, not editing a patient's DNA,' said senior study author Dr Carl June, also at the University of Pennsylvania.
After a short course of chemotherapy, the three patients (who had already been matched for a specific antigen subtype needed for the therapy to work) were given a single infusion of their genome-edited T cells. Blood samples from the patients showed that these altered T cells expanded and survived. None of the patients have yet responded to the treatment but so far no serious adverse reactions have been seen. According to a report by AP, a further 15 patients are scheduled to receive the therapy to assess its safety.
'I'm just so excited about this,' CRISPR pioneer Professor Jennifer Doudna at the University of California, Berkeley, who was not involved in the study, told NPR. 'It's an important step on the path toward using CRISPR/Cas genome editing in patients and shows the potential of this technology to be a safe and effective therapy.'
'It's very early, but I'm incredibly encouraged by this,' Dr Aaron Gerds, a cancer specialist at the Cleveland Clinic in Cleveland, Ohio, also not involved in the study, told AP.
Dr Stadtmauer is due to present the findings at the American Society of Hematology's annual meeting in Orlando, Florida next month.