Actavis and Allergan are merging in a cash-and-stock transaction worth around $66 billion, or $219 per share. The companies said in a joint statement on Monday that the merger will double sales of Actavis’s North American Specialty Business. The deal quashes Valeant’s months-long attempt to takeover Allergan. “We have seen the announcement that Allergan and Actavis have made . . . Valeant cannot justify to its own shareholders paying a price of $219 or more per share for Allergan,” Valeant’s CEO J. Michael Pearson said in a statement.

Improve-IT clinical trial results show that Merck’s cardiovascular drug Vytorin works. Analysts have been waiting for the results with a bit of dread – Forbes titled a November 13 story “A Day of Reckoning Approaches for Merck and its Critics,” giving a brief drug history, which boiled down to questions about whether the drug, which combines cholesterol-lowering Vytorin (Zocor) and Zetia, which lowers LDL cholesterol, prevented heart attacks, even though Merck had not supported Zetia claims. Monday’s news caps 10 years of anticipation, boosting Merck, and possibly the emerging class of PCSK9 cholesterol fighters: Regeneron’s CEO Leonard Schleifer told Bloomberg in an earlier interview that a positive Merck result would be “good news for us if people have further confidence in the LDL pathway . .  .  suppose this didn’t work and people lost confidence. That would be a disaster.” The company unveiled the results at the American Heart Association Scientific Sessions Monday.

Pfizer is coughing up $850 million to scoop up rights to Merck KGaA’s experimental cancer drug MSB001718C, with the possibility of paying a total of $2 billion to the German pharmaceutical company if the immuno-oncology drug hits its regulatory milestones. Bloomberg reports that the deal signals Pfizer is no longer interested in pursuing AstraZeneca.

The FDA has done a 180, approving Genzyme’s Lemtrada (alemtuzumab) as a third-line treatment for relapse-remitting multiple sclerosis. Friday’s approval includes a boxed warning about “serious, sometimes fatal autoimmune conditions,” and will be available through a restricted distribution program. The drug requires two doses a year, and the approval means Genzyme now has two FDA-approved MS drugs: the infusion Lemtrada and the daily oral Aubagio (teriflunomide).

Phase-III trials of Bristol-Myers Squibb’s cancer drug Opidvo (nivolumab) show that the anti-PD-1 drug increased the survival rates of treatment-naïve melanoma patients compared to chemotherapy, with a one-year survival rate of 73% compared to 42%, and a 58% decrease in risk of death. The company said in a statement that the CheckMate-066 clinical trial results “represent the first time a PD-1 immune checkpoint inhibitor has shown a survival benefit in a randomized Phase III trial.” The WSJ notes that previous nivolumab tests have been “single arm” studies in which all patients received the experimental treatment.