They could never reveal the terms of such an agreement before the terms were met. If they did so, no doubt the share price would be driven up, but it would have to be denied as it would violate the terms of the agreement. If there is a threshold price that Merck agreed to, it's a price that LP must reach without any serious discussion of such an agreement.
Even if LP said that there was a future agreement, it would drive the price up and violate the agreement if no details were released. It's just not done.
On the other hand, if a hostile bid was submitted to acquire the company management must announce it. They can certainly recommend against it, and such an offer will normally send the price up to near the price being offered, but it must be announced. Such offers are rare, but not unheard of, and if made could start a bidding war that would be a thing of beauty to shareholders.
Gary
Bullish