New Blood Test for Cancer Patients Makes Treatment Safer and More Effective

Scientists from RMIT University and the Doherty Institute in Australia have developed a new blood test that could screen cancer patients to help make their treatment safer and more effective. The first-of-its-kind test can rapidly assess how effective different polyethylene glycol (PEG)-based nanomedicines are at killing cancer cells and minimizing side effects using just a drop of blood from people with leukemia, a type of blood cancer.

Nanomedicines comprise tiny particles, much smaller than a cell, that interact with the body in precise ways. These tiny particles are designed to carry drugs directly to diseased cells, such as cancer cells, with the aim of sparing healthy ones. Nanomedicines, including Doxil, Onpattro (patisiran) and Vyxeos, have been approved for clinical use in Australia and the United States, while others are emerging but not yet being used in healthcare settings.

The test was developed based on a study that evaluated three different PEG-based nanomedicines on the blood of 15 people with leukemia. The researchers added the nanomedicines separately to blood samples, which were incubated at 37 degrees Celsius for one hour.

“We assessed how well the different nanomedicines targeted cancers in the blood, as well as healthy cells,” said Yi (David) Ju, PhD, an Australian Research Council DECRA Fellow at RMIT University. “That way we could determine which therapies were most effective for different people.”

Findings showed that differences in people’s immune systems affect how well these therapies worked against cancer cells, as well as side effects. Specifically, the researchers observed the difference in anti-PEG antibodies present in each individual’s blood samples. “The greater the presence of anti-PEG antibodies in people’s blood, the less effective these therapies were at killing cancer cells — in fact, these therapies were more toxic to healthy cells.”

Doxil, which is a common nanomedicine used to treat ovarian cancer, AIDS-related Kaposi’s sarcoma and multiple myeloma, was found to be affected strongly by the anti-PEG antibodies. This means that for some people, the therapy was targeting healthy cells involved in the blood’s immune response more than cancer cells. The researchers note that Doxil is not used to treat leukemia in clinical settings. The experiments showed that Doxil was still the most suitable option for some of the individuals tested compared to the other nanomedicines. The most effective targeted nanoparticle against leukemia was the team’s own formulation of pure PEG nanoparticles.

This study will help guide the development of next-generation cancer nanomedicines and improve the selection of patients for personalized treatments.