A combination of immunotherapies may increase the formation of memory T cells and lead to a more lasting response, according to findings from a study presented at the American Association for Cancer Research’s 2018 annual meeting.

Memory T cells, a subset of regular T cells, “remember” responding to a previously encountered invader such as cancer and are able to more quickly and efficiently mount a response if cancer relapses.

Researchers found that in the case of anti-CTLA-4 and anti-
PD-1 immunotherapies, combining the treatments was more effective than using anti-PD-1 alone, thanks to anti-CTLA-4’s ability to increase memory T cell levels.

Patients who receive anti-PD-1 have an average response rate of 30% but a two-year relapse rate of 25% after treatment ends. Those treated with anti-CTLA-4 have a response rate of 11%, and 22% are likely to survive at least 10 years.

The researchers said that the findings may help future studies identify immunotherapy treatment regimens that enhance both response rates and generation of memory T cells to prevent relapse.