Researchers at the University of Turku, Finland, have taken a step towards more personalised and effective cancer treatments. A new study has identified the conditions under which the antibody drug bexmarilimab can activate the body's own defence system against cancer, and how to identify patients who will benefit from the drug.

Bexmarilimab has the ability to “wake up” macrophages, a type of immune cell, to act against cancer. The study found that this activation occurs especially when the tumour microenvironment is immunologically silent. Moreover, in the healthy tissue adjacent to the tumour, bexmarilimab was shown to trigger B cell–mediated immune responses, regardless of how sensitive the neighbouring tumour was to the treatment. This suggests that the drug may have immunological effects beyond the tumour itself.

New tool for patient selection

By utilising previous knowledge about the changes bexmarilimab causes in tumours, researchers were able to demonstrate the benefit of bexmarilimab by measuring the upregulation of five different genes (gene signature). In the future, this could enable more accurate patient selection and improved treatment outcomes.

“This gene signature gives us a tool to identify patients whose tumours are likely to respond to bexmarilimab. Supporting treatment decisions with gene signatures measured from the tumour may help target therapies to those who are most likely to benefit. The next step is clinical validation of the signature, which could enable its use in more precise patient profiling”, explains Jenna Rannikko, Doctoral Researcher and lead author of the study.

The study utilised patient-derived tissue samples that closely mimic the interaction between tumours and the immune system. By measuring treatment response in these tissues, the researchers observed similar patterns to those seen in clinical trials of bexmarilimab.

Promising future for Finnish immunotherapy

Bexmarilimab, developed in Finland, has shown promising results in several types of solid tumours. This new study adds important insights into how bexmarilimab can be used most effectively in the future.

“Our findings suggest that by better understanding the tumour microenvironment, we can tailor immunotherapies to the patients who are most likely to benefit”, says Associate Professor Maija Hollmén, the study’s principal investigator. “In addition, understanding the factors that influence treatment efficacy may help expand its use to new patient groups in the future.”