NEW YORK (TheStreet) -- Shares of Arrowhead Research  (ARWR - Get Report) fell 6.63% to $7.47 in afternoon trading Tuesday after Jefferies downgraded the biopharmaceutical company to "Hold" from "Buy" and slashed its price target to $9 from $30.

The stock closed at $8 on Monday.

Arrowhead rose Monday after the company announced a new permission from the Food and Drug Administration.

The FDA informed Arrowhead that it can now proceed with a multiple-dose Phase 2b clinical study of ARC-520, the company's clinical candidate for the treatment of chronic hepatitis B infection, under an investigational new drug (IND) application previously filed with the FDA, Arrowhead said in a statement.

"This notification from the FDA allows us to begin a multiple-dose Phase 2b study of ARC-520, and we are working diligently to get treatment sites up and running," said Chief Operating Officer and Head of Research and Development Bruce Given, M.D.

"Our goal is to gain site IRB approvals and perform site initiation visits to begin recruiting and enrolling patients for this study in about a month," he continued. "We are also working with various regulatory agencies outside of the United States to initiate additional Phase 2b studies."

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