Reducing the dose of cancer drugs could open tumors to immunotherapy

Research at the Harry Perkins Institute of Medical Research in Perth has shown that administering cancer drugs at a dose 100 times lower than standard protocols can improve the tumor's response to immunotherapy.

Perkins' head of the cancer microenvironment department, Professor Ruth Ganss of the University of Western Australia (UWA), said the new research had shown an alternative route to high-dose cancer drugs in the fight against stubborn cancers such as melanoma, brain tumor or pancreatic cancer.

Prof. Ganss has dedicated her life to studying the microenvironment around solid tumors. This microenvironment consists of “sticky” supportive tissue and blood vessels that feed the cancer and make the tumor impenetrable to cancer drugs and immunotherapy.

Prof. Ganss’s latest research, published this week in the Journal of Clinical Investigationsshowed that when the dose of cancer drugs was significantly reduced, the tumor initially grew, but then the blood vessels surrounding the tumor returned to normal, allowing the immunotherapy to penetrate the tumor and be more effective.

“The cancer drugs we are interested in are already clinically approved. This gives us the opportunity to propose new dosing and timing protocols for patients,” said Prof. Ganss.

“Our clinical staff were excited by the results, which demonstrate an alternative method for co-administering drugs and immunotherapy.

“The next phase of our research is a clinical trial in which we will analyze tissue samples from patients with these difficult-to-treat cancers.

“My team and I are excited that we have found new ways to modulate cancer blood vessels using drugs that are already in clinical use. Now we can hopefully achieve a result that will lead to better, more effective treatments for the most seriously ill patients and prolong their lives.”

Two other researchers from Perkins, Professor Jonas Nilsson, Head of the Melanoma Research Department, and Professor Alistair Forrest, Head of the Systems Biology and Genomics Department, were part of the research team, as were scientists from the United States and Germany.