It could actually be good for Moderna. The "dreaded" comes from getting all the way into a phase 3 and the numbers come out ineffective.
Imagine the hit to Moderna's stock price if they reported the P2 trial was stopped because Moderna added to Keytruda was ineffective at the first read.
This kind of headline is dreaded because it flushes hundreds of millions down the drain.
Moderna and MRK appear to be balls to the wall moving on other indications before they even start P3 on melanoma. Lotsa guts spending lotsa bucks before they know they have a winner......or maybe they have so far undisclosed data on the P2 (like 2 year plus survival) that they are convinced melanoma is a slam dunk.