Heating up tumours could make CAR T therapy more effective
When a heating technique called photothermal ablation was combined with the infusion of CAR T cells, it suppressed melanoma tumour growth for up to 20 days in mice…
A pre-clinical study led by scientists at the University of California Los Angeles Jonsson Comprehensive Cancer Center suggests that heating solid tumours during CAR T-cell therapy can enhance the treatment’s success.
The researchers found that when a heating technique called photothermal ablation was combined with the infusion of CAR T cells, it suppressed melanoma tumour growth for up to 20 days in mice. Among the mice that were treated with the combination, 33 percent were still tumour free after the 20-day mark.
T cells that have been genetically engineered with chimeric antigen receptor, or CAR, have successfully been used to treat many patients with lymphoma and leukaemia. But CAR T-cell therapy has been less successful for treating solid tumours because the tumours have a protective micro environment, which makes it harder for the CAR T cells to break into the tumour and keep the T cells activated.
The UCLA scientists decided to test whether combining CAR T therapy with photothermal therapy could overcome that obstacle.
Photothermal therapy is a minimally invasive technique that uses heat from laser energy to kill cancer cells; it is already being used to treat a variety of cancers and other medical conditions.
The researchers tested a mild hyperthermia of about 40°C to see if it could help enhance the CAR T cells to better attack the tumour.
The UCLA-led team tested the technique in mice that were injected with human melanoma tumours. A photothermal agent was injected into the tumours and then irradiated with the laser to heat them. Then, CAR T cells were injected intravenously. Raising the temperature of the laser to about 40°C helped expand blood vessels associated with the tumour, enhancing T-cell growth.
By enhancing the power of CAR T-cell therapy, the technique could eventually improve the prognosis for people with hard-to-treat solid tumours. The researchers will continue testing the strategy in animals to optimise the heating duration and temperature before determining whether it can be tested on humans.