This bad boy went berserk in April 2013 , flied away from this and entered into a channel, which by the way, it broke exactly one year later, April 2014. Since then Regeneron had fallen back to this , and it tested the high 270s support 3 times in the past month and successfully rebounded. I do believe the biotech selloff is over, however, a further selloff of other momo ( TWTR , TSLA , etc.)this week spoiled the party and botched this long anticipated revocery. But this doesn't mean the party is over, it just means it's postponed.
Plus, a big plus, Sanofi bought god knows how many shares of REGN at 310 in March and now owns a big chunk(30% ?) of the company. If Sanofi thought 310$ a share was fair, what's holding us back from snapping up REGN 280$ a share? And given the current M&A frenzy, who knows right?