Hubert Chen has been appointed chief medical officer of San Diego biotech Metacrine. Chen most recently worked as chief medical officer of Pfenex (NYSE American: PFNX). Metacrine develops drugs for liver and gastrointestinal diseases. Last year, Metacrine raised $22 million in Series B financing. The company plans to test its lead drug, MET409, as a treatment for the fatty liver disease nonalcoholic steatohepatitis.