UPDATE: Piper Jaffray Downgrades Isis Pharma to Underweight

Piper Jaffray earlier downgraded Isis Pharmaceuticals, Inc.

from Neutral to Underweight and raised the price target from $12.00 to $20.00. The firm's Ted Tenthoff believes the company's current valuation cannot be justified given the limited ownership of a majority of the pipeline. With shares of Isis Pharma down 4.5 percent to $29.54 at last check, Tenthoff's new price target implies potential downside of about 32 percent.