Anti-tumour activity

A recent early-phase clinical trial has found that combining an anti-angiogenesis agent – which blocks blood vessel formation – with an immunotherapy agent in patients with advanced kidney cancer showed promising anti-tumour activity and no unexpected side effects.

The study, involving the combination of xitinib (Inlyta) and pembrolizumab (Keytruda), was presented as part of the ASCO Genitourinary Cancers Symposium in San Francisco, US, and context and additional information about the primary endpoint will be published in The Lancet Oncology.

Axitinib inhibits the process of blood vessels forming to feed a tumour, and Inlyta was approved by the US Food and Drug Administration (FDA) in 2012 for the treatment of patients with advanced kidney cancer in whom one prior systemic therapy has failed. It has also been shown to be selective in how it works, which results in a strong effectiveness to toxicity ratio.

Pembrolizumab is the immunotherapy agent and blocks a self-defence mechanism used by cancer cells to evade attack and destruction by the body's immune cells. It is FDA-approved for the treatment of patients with several cancer types but has only had limited study in patients with kidney cancer.

In contrast to earlier attempts to develop combinations of anti-angiogenesis agents and checkpoint-inhibitor-based immunotherapies to treat patients with advanced kidney cancer that resulted in high levels of toxicity, the axitinib-pembrolizumab combination was sufficiently tolerable to enable the agents to be given their FDA-approved single-agent dose levels.

“Our results are unprecedented. The combination doubled the efficacy of the drugs when used alone and the treatment was found to be tolerable,” said Dr Michael B Atkins, Deputy Director, Georgetown Lombardi Comprehensive Cancer Center and Principal Investigator for the study. “Specifically, over 90 per cent of patients exhibited tumour shrinkage and the disease was kept under control for a median of over 20 months.”