Potential cancer break-through treatment halted after 2 trial patients die

© Jean-Paul Pelissier
Trials of an experimental therapy to treat Leukemia have been halted by US authorities after two patients died last week. The treatment developed by Juno Therapeutics looks to reprogram cells to find and eliminate cancer.

The two patients who passed away died from swelling of the brain, which occurred after the chemotherapy agent fludarbine was added to the treatment program. Doctors began to see an increase in "severe neurotoxicity," said CEO Hans Bishop.

"The last week has been difficult and humbling for everyone involved, in particular, of course, the physicians and the patients' families," Bishop added, according to the AP.

This prompted the US Food and Drug Administration (FDA) to temporarily shut down the CAR-T therapy program known as JCAR015.

A similar death was reported in May, but both the FDA and Juno said there were “compounding factors.” 

The therapy works by looking to extract immune system T cells from a patient, then alter their DNA to help spot and eliminate cancer cells in the person’s body. The modified cells are then returned to the patient. 

"This sort of thing is incredibly common in new drug development. It's unfortunate, but I don't know how you avoid it," Dr Otis Brawley, chief medical officer for the American Cancer Society, told AP. 

Those enrolling in the program normally receive doses of chemotherapy before receiving the CAR-T therapies as this makes the cancerous tumor more vulnerable to the CAR-T cell. The experimental medicines can cause the buildup of toxic debris from the killed-off tumor cells and this can damage healthy tissue. This inflammation is normally controlled through the use of steroids. 

A researcher working on the study says more than 300 patients have been treated with similar therapies in the US without suffering any unwanted side effects. There were 20 patients on the JCAR015 program, and hopes of raising this to 90. Juno Therapeutics is now seeking FDA permission to continue the program without fludarbine. 

"These are relatively rare events, so I don't think it changes the fundamental promise or the long-term plan here," said Dr Jae Park of Memorial Sloan Kettering Cancer Center in New York, AP reports.