It’s not uncommon for partnership talks focused on one drug to escalate into a full-on buyout. And that's just what happened with Merck & Co.’s $2.7 billion deal for ArQule. ArQule started looking for a co-development, profit-sharing partnership for its BTK inhibitor ARQ 531 around 2018. But after Merck decided it wanted “greater control,” the industrious New Jersey pharma instead negotiated an acquisition deal in 20 days. Initially, it wasn’t just Merck interested in ARQ 531. At least six companies—and we have a few guesses who—were intrigued enough to dig into due diligence at some point between 2018 and 2019, according to a securities filing.