"Does BPs' sudden enthusiasm in ADCs have anything to do with DCVax-L?"
Forgive my ignorance but what makes you think there is a connection? Any kind of immuno-therapy is potentially more effective in combination with DcVax but do you know of any papers or trials linking any ADC with DcVax?
Merck investing billions in ADC's tells you that Merck has chosen a different path a for cancer treatment. Different and at the same time similar to DCVAXs MOA. Merck investing many billions in ADCs makes it more unlikely that they will choose DCVAX as their path of a new cancer treatment generation.
Ofcourse there are many other big pharma out there