New brain cancer therapy showing promise

Researchers at the University of New Mexico Comprehensive Cancer Center say a new two-drug combination is showing promising results in the battle against a deadly brain cancer, glioblastoma.

In a presentation of early clinical trial data to the 20th Annual Scientific Meeting of the Society for Neuro-Oncology, UNM physician scientists reported that a large number of study participants responded well to the drug combination.

The clinical trials test the combination of temozolomide and indoximod. Temozolomide kills cancer cells by damaging their DNA, but cancer cells can become resistant to it. Indoximod is a new immunotherapy drug made by NewLink Genetics, Inc. It disrupts a cellular process that cancer cells use to hide from the immune system and allows the immune system to recognize and attack the cancer. Half to 90 percent of glioblastoma cells use this cellular process so indoximod helps a patient's own immune system to find and attack their tumors.

"This is one of the first clinical trials testing an immune checkpoint inhibitor in glioblastoma," says UNM's Olivier Rixe, MD, PhD, national principal investigator for these clinical trials. "It shows that indoximod is the first such therapy to produce an objective response in glioblastoma, an important milestone in the treatment of this serious condition."

Glioblastoma is a particularly aggressive type of brain cancer - only about one fifth of adults diagnosed with it survive two years or more after their diagnosis.

Rixe and his colleagues reported that four out of the 12 people in the phase 1b clinical trial responded strongly to the drug combination - their cancers did not grow for six months or more. All 12 people in that trial had already become resistant to standard therapies. They also reported that 40 people have joined the phase 2 trial so far, with plans for 132 people to eventually join. Of these 40, nine have been on the drug combination for six months or more, and seven of these nine are responding to the treatment so far.

Rixe, the associate director for clinical research at the UNM Comprehensive Cancer Center, is working closely with a UNM team of physicians on the trial, including M. Omar Chohan, MD, a neurosurgeon who specializes in surgery for tumors of the brain and spinal cord; Gregory Gan, MD, PhD, a radiation oncologist who is an expert in the radiation therapy of brain tumors; and Yanis Boumber, MD, PhD, a newly recruited medical oncologist to the UNM Cancer Center who is an expert in cancers of the lung, brain and spinal cord, as well as early phase clinical trials.