Pharma Stock More Than Halved on Drug Trial Flop

The shares are pacing for their worst day ever

The shares of AC Immune SA (NASDAQ:ACIU) are down 68.3% at $3.40, after the company and partner Roche said they're halting late-stage trials of Alzheimer's drug crenezumab. The medical research concern said the drug would likely fail to meet its primary goal. ACIU stock is now plumbing new record lows -- dropping to $3.34 earlier -- and on pace for its worst day ever.

Prior to today, AC Immune shares had been struggling to overtake the $12 area, which is about a 50% Fibonacci retracement from the equity's mid-July peak above $17.40 to its early October lows around $7. The security had been bouncing off the $8 area in recent months, but is trading well below that level today.

In response to today's news, Jefferies cut its price target to $18 from $32. Leerink, meanwhile, slashed its ACIU price target to $11 from $18. However, both new targets still represent steep upside for the shares from current levels.

Other analysts could follow that lead, too, with the stock currently sporting two "strong buy" ratings and one "buy," with not a single "hold" or "sell" in sight. Plus, the consensus 12-month target price of $17.50 -- an area ACIU hasn't hit since it first began trading in 2016 -- represents a whopping 422% premium to current levels. Should ACIU continue to struggle, a round of potential downgrades and additional price-target cuts could translate into more headwinds.