Scientists from The Institute of Cancer Research, London, have successfully tested whether a cancer treatment is working or not by measuring the metabolic changes in the blood as "testable indicators."

"We have shown that assessing a patient's metabolites can be a quick and simple way of assessing whether a cancer drug is specifically hitting its intended target in the body. Our study is an important step in the development of new precision cancer therapies, and is the first to show that blood metabolites have real potential to monitor the effects of novel agents," said Dr Florence Raynaud, Senior Researcher in the Clinical Pharmacology and Trials Team at The Institute of Cancer Research, London, in a statement.

The study, published in the journal Molecular Cancer Therapeutics, suggests that measuring the effects of cancer treatment in the levels of metabolites can be used to assess whether a certain cancer drug is hitting its intended target.

For the study, researchers conducted a preclinical trial on mice with cancers that had defects in the PI3K pathway, a molecular pathway in cancer cells, and a clinical trial involving 41 patients with advanced cancers.

For the preclinical trial, researchers analyzed the metabolite levels in the blood of mice using a sensitive technique called mass spectrometry. The researcher discovered 26 blood metabolites that were low before the therapy have risen considerably after being treated with pictilisib, a drug designed to specifically target PI3 kinase.

On the other hand, researchers measured the levels of 180 blood markers in each participant during the Phase I of the clinical trials. Researchers found out that 22 out of the 26 blood metabolites found in the mouse models have once again rose in response with the treatment.

Researchers noted an increase in the blood metabolites in both the mouse and human model after a single dose pictilisib. And when the treatment was stopped, the blood metabolites began to decrease again. This suggests the increase and decrease of blood metabolites are related with the drug.

Researchers believe that blood metabolites has great potential to be used to test if a certain drug is working, despite its natural variations depending on the time of the day and food consumed.

"By monitoring metabolic signals in the blood, we could make informed decisions about drug development without having to wait years to see the final results of large clinical trials. And our method could eventually be used to monitor patients routinely during the course of treatment, as a quick and easy way of assessing whether a drug is still working, or whether treatment needs to be adapted," Professor Paul Workman, Chief Executive of The Institute of Cancer Research, London, and co-author of the study, explained in a press release.