Mannkind pressures drug stocks By: MarketWatch February 11, 2011 at 11:39 AM EST Shares of Mannkind Corp. sank 20% on news that it was laying off 41% of its workforce in order to focus its resources on its troubled inhaled insulin product Afrezza. Read More >> Related Stocks: Abbott Laboratories Biocryst Pharma Inc Neurocrine Bioscienc