Merck was already a customer of the contract manufacturer that specializes in making biologics produced in yeast and bacteria, so at least it has some experience with what it's buying.
Assuming Merck didn't overpay -- terms weren't disclosed -- the purchase seems like a good idea. It could have built its own plant, but that would have taken time and money. This way, Merck gets manufacturing capabilities that are up and running, staffed by people who know what they're doing. Not to mention, Avecia is a contract manufacturer, so it has probably become efficient at manufacturing so it can win outsourcing bids.
Merck says it'll "engage in discussions with individual customers relating to their specific ongoing and future biological process development and manufacturing needs after the transaction is closed." I'm not sure if that means it plans to try to retain customers like Dyax
I understand Merck's and Pfizer's
The push further into branded biologics has to make you wonder, though. Genentech and Amgen