Arrowhead Pharma Shares Plummet 60% On Discontinued Drug Development

Arrowhead Pharmaceuticals Corp. shares plummeted in the extended session Tuesday after the drug developer said it was discontinuing the development of some drug candidates and refocusing resources. Arrowhead shares dropped 60% to $1.77 after hours. The company said it would no longer pursue the development of three hepatitis treatments that use its "EX1" delivery vehicle because of substantial delays foreseen in regulatory approval. Arrowhead also said it would trim its workforce by 30%. Arrowhead said it would focus on hepatitis B treatments and others, especially those where the company is partnered with biotech giant Amgen Inc. .