If a patient with MSI-H endometrial cancer slowly progresses on single-agent pembrolizumab, would you add lenvatinib?

This is an important question without a defined answer at this time. In a prior phase 2 trial examining cabozantinib + nivolumab in endometrial cancer, a small exploratory cohort of patients treated with prior IO was included. Of 20 patients who received prior IO, six patients responded and eight had SD when treated with combination TKI + IO (Lheureux et al., JCO 2020). This preliminary data suggests that patients who receive single agent IO, and progress after response, may benefit from addition of a TKI, such as lenvatinib. It will be important for us to design appropriate trials that will better inform the above question.