Maybe they do intend to go alone on M-118? Or at least posture that way for negotiations.
I seriously doubt that for the reason you cited: cost.
What is the estimate on how much it would cost to run a phase 2b and phase 3 on M-118?
The short answer is: too much for MNTA to afford on its own, assuming that the point of the trial is to measure adverse clinical outcomes over a meaningful period of time for patients randomized to M118 or an active control regimen.
Thanks to the wonders of modern medicine, ACS trials that seek to show superiority or non-inferiority in clinical outcomes have to be very large because the overwhelming majority of patients in all trial arms will do OK.