Roche stays mum about FTC, CMA reviews as $4.3B Spark deal faces yet another delay. What's up?

Just what exactly is holding up Roche’s $4.3 billion acquisition of Spark Therapeutics?

That’s the question that Spark investors are pondering as the Swiss drugmaker announced extension #6 of their tender offer to let antitrust watchdogs from both sides of the Atlantic complete their reviews.