Immunotherapy shows promise against advanced leukemia: study

An experimental therapy called immunotherapy has shown promise in treating some patients with advanced chronic lymphocytic leukemia (CLL), the most common form of adult leukemia,U.S. researchers reported Wednesday.

In an early clinical trial, eight of 14 patients with advanced CLL responded to the therapy that trains their own immune cells to attack tumor cells, with some complete remissions continuing past four and a half years, according to results published in the U.S. journal Science Translational Medicine.

"The durability of the remissions we have observed in this study are remarkable and have given us great hope that personalized cell therapies are going to be important options for patients whose cancers are no longer treatable with standard approaches," lead author David Porter, professor at the University of Pennsylvania, said in a statement.

The therapy, known as CTL019, begins with each patient's own T cells, which are collected through a procedure similar to dialysis and then reprogrammed to contain an antibody-like protein known as a chimeric antigen receptor (CAR) that can target and destroy leukemia cells.

For the study, all patients had cancer that had relapsed or continued to progress after receiving multiple conventional therapies, and few were eligible for bone marrow transplants.

The therapy proved effective in eight patients, four of whom achieved a complete remission without relapse, they said.

Of these four patients, one died while in remission at 21 months after the therapy due to infectious complications that occurred after removal of a basal cell carcinoma on his leg.

The three other patients remained alive at the time of this analysis with no evidence of leukemia at 28, 52, and 53 months after receiving the therapy.

An additional four patients achieved partial responses to the therapy, with responses lasting a median of seven months.

Analysis of patients who experienced complete remissions showed that the modified T cells can multiply and persist in the body for years.

"This suggests that at least some of the CTL019 cells retain their ability to hunt for cancerous cells for long periods of time," said senior author Carl June, professor at the University of Pennsylvania.

Side effects for those patients who responded to the therapy included varying degrees of flu-like symptoms, and some required intensive care, but all of them recovered in the end.

"The patients in this study are pioneers, whose participation has given us a foundation of knowledge and experience on which to build this new approach to help more patients," Porter added. Endit