Of patients with advanced leukemia who were given immunotherapy for a study, 93 percent went into remission after the procedure, showing that genetically engineering disease-fighting immune system cells has great potential in fighting the disease.

The study involved 29 advanced leukemia patients, all adults who have either relapsed or are not responding to other forms of treatment. It was designed to address challenges the immune system faces when dealing with cancer, introducing genetically engineered T-cells from the patient incorporated with a chimeric antigen receptor (CAR) and giving the T-cells the ability to identify and attack cancer cells bearing CD19, a specific marker.

Carried out by the Fred Hutchinson Cancer Research Center, the study's aim was to assess how safe it was to use genetically engineered cells, laying down the foundations for improvements.

To genetically engineer T-cells from the patients, a special virus was injected into the cells to deliver DNA instructions necessary for producing the CAR within them. The T-cells were then cultivated into billions before being administered back into patients after they received chemotherapy.

After a few weeks, the patients were evaluated, and 27 out of the 29 were found to have zero traces of the cancer. It would appear the CAR T-cells were able to eliminate the disease wherever it appeared in the participants' bodies.

One of the participants that didn't go into complete remission during the first infusion eventually re-enrolled and was given a stronger dose of T-cell infusion before finally also achieving remission. However, not all stayed cancer-free. Some relapsed and received treatment again, while two turned out to have immunity against the CAR T-cells.

According to the researchers, it's too soon to say what kind of long-term effects immunotherapy has. They have learned a few things that would allow them to redesign the treatment to lower adverse side effects.

"Patients who come onto the trial have limited options for treatment ... So the fact that we're getting so many into remission is giving these people a way forward," said study lead Cameron Turtle.

The study, which was published in The Journal of Clinical Investigation, received funding support from the Life Sciences Discovery Fund, Juno Therapeutics, the National Cancer Institute and private philanthropists.

Photo: Phil and Pam Gradwell | Flickr