Response to Cancer Immunotherapy May Be Affected By Commonly Used Medications

Bladder cancer patients treated with atezolizumab may face worse outcomes if they also take proton pump inhibitors.

Commonly used medications for acid reflux, heartburn, and ulcers may be associated with worse outcomes for patients with bladder cancer who are treated with the immunotherapeutic atezolizumab, according to a study published in the AACR journal Clinical Cancer Research

About 30 percent of patients with cancer take the medications, known as proton pump inhibitors (PPI). Researchers in Australia investigated whether PPIs influence the effectiveness of atezolizumab (Tecentriq), a type of cancer medication known as an immune checkpoint inhibitor. 

The scientists found that in patients with urothelial carcinoma – commonly referred to as bladder cancer — who were being treated with atezolizumab and were also taking PPIs, the risk of death was 68 percent higher than in those not taking PPIs. They also had a 47 percent greater risk of the cancer progressing to a more advanced state and a 54 percent lower rate of responding to treatment. 

“PPIs are overused, or inappropriately used, in patients with cancer by up to 50 percent, seemingly from a perspective that they will cause no harm,” said Ashley Hopkins, PhD, an early-career research fellow at Flinders University in Adelaide, Australia, and first author of the study.  

“The findings from this study suggest that non-critical PPI use needs to be approached very cautiously, particularly when an immune checkpoint inhibitor is being used to treat urothelial cancer,” he said.