Radiation and chemotherapy treatments for cancers destroy tumours and healthy tissue alike, often leading to severe side effects.

Cancer immunotherapy approaches, which stimulate the immune system to selectively attack tumour cells, represent an opportunity to treat cancer without harming healthy cells.

While immunotherapy approaches have been successful against haematological malignancies, they have been less effective in eradicating solid tumours.

This is partially due to the ability of tumours to suppress local immune responses.

A major goal of cancer immunotherapies that are in development has been to improve the targeting of solid tumours.

A team led by Matthias Stephan at the Fred Hutchinson Cancer Research Center has developed a biopolymer delivery system that combines two synergistic immunotherapy approaches: CAR T cells and STING agonists, which stimulate the innate immune system.

In a study published this week in the JCI, they show that this method of activating the immune system at the site of CAR T cell delivery eliminates tumours more effectively than CAR T cell therapy alone.

The researchers implanted a biopolymer scaffold to co-deliver STING agonists and CAR T cells to tumour sites in a mouse model of pancreatic cancer and melanoma.

The STING agonists improved the function of CAR T cells compared to CAR T cells that were delivered alone.

However, the STING agonists also triggered anti-tumour responses within the mice that prevented tumour metastasis.

These findings provide promising support for combined immunotherapy approaches for treating solid cancers.

Source: JCI