REPURPOSING A COMMON REFLUX DRUG TO EASE CHEMOTHERAPY NAUSEA

As if coping with a breast cancer diagnosis and treatment isn’t enough, some patients are then plagued by nausea that lasts for days, well past the point at which chemotherapy drugs are out of their system.

It’s distressing both for patients and the clinicians committed to making them more comfortable. Medical oncologist Dr Navin Wewala says fear of side effects is so significant for some patients that it makes them consider omitting potentially life-saving treatment.

While drugs are available to manage nausea during chemotherapy, the incidence of delayed chemotherapy-induced nausea and vomiting (CINV) remains high, affecting more than half of all patients.

Starting with the hypothesis that chemotherapy and steroids change the gastric environment and irritate the stomach lining, Dr Wewala and Dr Richard Isaacs collaborated with Cancer Trials New Zealand to run a clinical trial testing whether Pantoprazole, a commonly used medication for treating gastric reflux and heartburn, could ease post-chemotherapy nausea.

Pantoprazole is a proton pump inhibitor, in a class of drugs that work by reducing production of stomach acid. Dr Wewala says some oncologists have been prescribing the drug for patients who report that it reduces symptoms, but a clinical trial was an important step in proving its effectiveness.

“The drug is very safe, but we also needed to know that benefits outweigh risks. We don’t want to give it to everyone without proving that it works and is safe in this specific situation.

“And even though some clinicians believed in it and liked using it, there were others who didn’t think it was helpful.”

The PantoCIN study, conducted from 2019 to 2021, involved 160 patients from 10 cancer centres across New Zealand, with all participants trialling both the medication and a placebo. This was a discretionary funding projects supported by our generous donors to Breast Cancer Trials.

Dr Wewala says the results were encouraging, indicating Pantoprazole completely alleviated delayed CINV for one in every eight people, and that the overall group reported reduced nausea.

“When you tackle the subject of reducing nausea, you have the potential to improve people’s more general health while they’re managing cancer,” he says.

The results will give clinicians more certainty and boost confidence in prescribing Pantoprazole to reduce nausea.

“If we have drugs that can help, that are already available and affordable, and are proven to be safe and well tolerated, then it’s a shame not to establish that they’ve got another use.”

Publication:

Navin Wewala, Katrina Sharples, Yujin Kim, Sarah Benge, Robert Cartwright, Louise Clement, Ying Huang, Richard Isaacs. PantoCIN: Pantoprazole’s effectiveness as prophylaxis against delayed Chemotherapy-Induced Nausea and Vomiting (CINV) in patients receiving adjuvant or neoadjuvant breast cancer chemotherapy [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr PD8-01 https://doi.org/10.1158/1538-7445.SABCS22-PD8-01