Auckland Clinical Trial Aims To Make Cancer Drug Safer

Three women are running a cancer clinical trial with a difference at the University of Auckland and Auckland City Hospital.

While most cancer research focuses on discovering new treatments, Dr Nicky Lawrence and Professor Nuala Helsby from Waipapa Taumata Rau, University of Auckland, and Auckland Hospital oncologist Dr Jane So are pooling their research talent to investigate a chemotherapy drug that has been widely used for about 50 years.

Patients are being recruited for a clinical trial that has a long-term goal of uncovering the reasons the chemotherapy drug, 5-fluorouracil (5FU), causes serious side effects in some patients.

“It’s a really old drug, but there are still all these undiscovered things about it.

“No one has put all the information together to say ‘ah, this is why we might be seeing the side effects',” says molecular medicine and pathology professor Helsby.

About five percent of patients suffer symptoms of cardiotoxicity, and in rare cases this side effect can be fatal.

Nevertheless, 5FU remains the “backbone” of chemotherapy treatment for stomach and bowel cancers, because it’s the most effective drug currently available, says Lawrence, who is a senior lecturer in medical oncology, an oncologist at Auckland Hospital, and director of Cancer Trials New Zealand.

The research team has received $149,421 from the Gut Cancer Foundation and $28,968 from the University's Te Aka Mātauranga Matepukupuku – Centre for Cancer Research for the two-year study. The Cancer Society and Canopy Cancer Care also provided funding.

This has launched with a pilot trial, which aims to find 10 patients who are willing to wear a Holter monitor for 48 hours, undergo three blood tests and provide urine samples. The data collected will help clarify what happens when 5FU affects the heart.

“We’re asking patients out of the goodness of their hearts to give their time for this research, on top of the shock of diagnosis and the rigours of their very first cycle of chemotherapy.

“It’s a lot to ask, but this research could help make this drug safer for patients in the long term,” says Helsby.

At present, patients go home from the hospital wearing a bag on their waist containing their 5FU infusion. The researchers are asking them to add the Holter monitor, which includes circles stuck on the skin with wires leading to a small device that records heart activity in an electrocardiogram (ECG).

Some people suffer chest pains while receiving 5FU and treatment is then stopped, because the risk of serious side effects is too high.

“If we could understand more about who is at risk, there might be ways to keep them on this treatment, rather than taking them off 5FU, which is the most effective drug available,” says Helsby.

The study could help oncologists predict when serious side effects are likely, says Lawrence.

“There’s no way of predicting it at the moment.”

Helsby suspects the side effects caused by 5FU could be associated with the way the body breaks down the drug.

“With chemotherapy, you’re trying to poison the cancer cells, but sometimes the person’s cells are poisoned too.

“We think there might be products people’s bodies make as they break down 5FU that could be causing these side effects, so we want to know who is making too much of these products,” says Helsby.

New software designed to pick up more subtle changes in ECGs from the Holter monitor will be tested by the research team.

If 10 patients can be found for the pilot study, the researchers hope to carry out a larger, national study.

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