CAR-T cell therapy is effective in mice with ovarian cancer, according to a study published in The Journal for ImmunoTherapy of Cancer.
The study authors, who work at Karolinska Institutet, hope that the discovery will pave the way for a clinical trial to see how effective the treatment is for women with the disease.
“This therapy is currently available for patients with blood cancer, and we want to investigate if we can use the method to treat ovarian cancer,” says the study’s joint last author Isabelle Magalhaes, docent at the Department of Oncology-Pathology at Karolinska Institutet. “Despite many improvements to the available therapy, the prognosis for women with ovarian cancer is still poor.”
Until now, CAR-T cell therapy has proved largely ineffective against solid tumours. “Tumours often arise in an environment that’s unfavourable for T cells, in part due to a low oxygen level,” says Jonas Mattsson, visiting professor at Karolinska Institutet, and the second joint last author. “This can cause attacking T cells to be neutralised, which impairs the therapeutic effect. So we wanted to examine if it would still work.”
Mice lived longer or were cured
Many ovarian tumours contain mesothelin, and the researchers tested three types of CAR molecule programmed to attack this particular protein.
All three CAR-T cells significantly prolonged the lives of the mice with cancer compared to those in the control group, with the type called M1xx CAR-T cells proving the most efficacious. The mice that were injected with T cells that express that particular molecule saw a reduction in tumour size and lived even longer than the others. Several of the mice were even cured.
“In several mice, there were no tumour cells left that we could detect, and the effect lasted just over three months after the treatment started. This is evidence that immunotherapy involving CAR-T cells that attack the mesothelin protein is a promising one for ovarian cancer,” says Professor Mattsson.
“Hopefully, this discovery will pave the way for a clinical study. Our goal is to predict the optimal conditions for producing CAR-T cells able to infiltrate and attack the tumour and survive in the bodies of women with ovarian cancer.”