Gritstone bio Inc. (NASDAQ:GRTS) shares are trading lower by 64.2% to $0.07 during Thursday’s session after the company announced it voluntarily filed for Chapter 11 restructuring. What Else: Gritstone Bio says the company plans to use the court-supervised restructuring to preserve value while exploring strategic alternatives. Gritstone is in talks with a potential bidder or plan sponsor and hopes to present a deal to the court soon. The company also says it remains focused on developing next-generation vaccines and immunotherapies, including its promising GRANITE cancer treatment, while conti…