Yes, Prins's group did do a small DCVax/ICI combo study, but I can't recall if that was first in man or first in mouse.
If they do embark on the long-promised Nivo/DCVax combo in recurrent, at least they plan a DCVax only arm, which I suspect would do at least as well, without any toxicity that the other arm may experience.
Nivo has already failed abysmally in recurrent, with PFS of 1.5 months...