Biohaven tumbles as migraine drug efficacy fails to impress investors
Biohaven Pharmaceutical Holding said its migraine treatment met the main goals in two late-stage studies but the efficacy data failed to differentiate when compared with rival treatments in a crowded field.
Shares fell as much as 50 percent in light premarket trading on Monday but pared losses to trade down 23 percent at $19 as volume picked up.
The stakes are high for Connecticut-based Biohaven, which entered a competitive field late and hopes to rival a treatment from Allergan Plc that reported strong efficacy data…