It looks to me like MM is expecting Merck to continue running...

It looks to me like MM is expecting Merck to continue running with VLA into phase 3. I just revisited the ABC interview in June 2016 (http://www.abc.net.au/news/2016-06-03/extended-interview-with-dr-malcolm-mccoll/7476824) and he says at the 6 minute point "and of course if we saw the results we were hoping to see in the Merck collaboration then we know Merck would want to continue to fund and increase investment". My interpretation is that Merck would push forward, and pay for, Phase 3 trials. I also note that at the AGM MM said something like "and the price just went up" - talking about the results publicised in October, so my take is that Cavatak has exceed "there results we were hoping to see".

He also says that the differentiator for the big IO drugs (Keytruda, Opdivo, Yervoy, etc) is the best combination, and it seems to be a conscious effort to not have partnered with everybody, so as to own as much as possible of the IP.

It seems the future is rosy, just need to be patient!