Management here - nothing is going to happen this year & who knows about next year. There are many variables which will dictate how things pan out. Layoffs will almost always occur toward the end of a year because budgets are done on a calendar year worldwide. The US is only a portion of a company that employs 116,000 people.
Novartis will always need someone to call on their customers. There will probably be fewer in the long run, but we will always need some salespeople. If you choose to ride it out all you can do is to do your job everyday and try not to worry. Of course you should have "plan B", but you can't dwell on whether or not we will have layoffs.