Relypsa Lost Major Ground; Feuerstein Tweets Favus Report Said 'Nothing New'

Shares of

were trading higher by more than 8 percent early Friday morning. The stock plunged more than 13 percent on Thursday following a bear research report by Elliot Favus of Favus Institutional Research. Adam Feuerstein, a senior columnist with The Street and known biotech expert, took to Twitter and said that the Favus' bear thesis contained "nothing new" and "echoes" a similar thesis presented by Andrew Berens, a biotechnology analyst at FBR Capital Markets.

The stock was in a downtrend before Thursday's steep selloff; Shares opened the new year around the $29 level. The stock traded recently at $22.28, up 5 percent in Friday's pre-market session.