What happened Shares of biotech company ArQule (NASDAQ: ARQL) rocketed 108% higher last month, according to data from S&P Global Market Intelligence. December's jump brought ArQule stock's 2019 gain up to a whopping 621%. For context, the S&P 500 returned 31.5% last year. Image source: Getty Images. So what We can attribute ArQule stock's powerful performance last month to Merck's (NYSE: MRK) Dec. 9 announcement that it plans to acquire ArQule. Shares surged to a closing gain of 104% that day. The all-cash, $2.7 billion deal values ArQule at $20 per share, representing a fat 107% premium over the stock's closing price of $9.66 on the previous trading day, Friday, Dec. 6. What does Merck want with ArQule? The main prize is its drug candidate ARQ 531, which is in a phase 2 clinical study as a treatment for B-cell malignancies. (B-cell malignancies include non-Hodgkin lymphomas and chronic lymphocytic leukemia.) In the press release, Merck Research Laboratories president Roger Perlmutter said, "This acquisition strengthens Merck's pipeline with the addition of these strategic assets including, most notably, ARQ 531, a compelling candidate for the treatment of B-cell malignancies." Now what The deal is expected to close in the first quarter of 2020. 10 stocks we like better than ArQuleWhen investing geniuses David and Tom Gardner have a stock tip, it can pay to listen. After all, the newsletter they have run for over a decade, Motley Fool Stock Advisor, has tripled the market.* David and Tom just revealed what they believe are the 10 best stocks for investors to buy right now... and ArQule wasn't one of them! That's right -- they think these 10 stocks are even better buys. See the 10 stocks *Stock Advisor returns as of December 1, 2019 Beth McKenna has no position in any of the stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. The Motley Fool has a disclosure policy.Source