The findings
Earlier research by the team indicated that if people developed high levels of anti-PEG antibodies from mRNA vaccines then future mRNA treatments for conditions including cancer may be less effective, as their bodies would clear the therapeutics more quickly. PEG is a commonly used compound in mRNA vaccines.
They also found individual immune responses played a significant role.
“In this latest study, we explored how different nanomedicine formulations work with blood from patients,” Ju said.
“We found that differences in people’s immune systems affects how well these therapies worked against cancer cells, as well as side effects.”
The team observed the difference in anti-PEG antibodies present in each individual’s blood samples, Ju said.
“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.