Aerpio Pharmaceuticals, Inc. filed SEC Form 8-K: Entry into a Material Definitive Agreement, Completion of Acquisition or Disposition of Assets, Unregistered Sales of Equity Securities, Material Modification to Rights of Security Holders, Changes in Control of Registrant, Leadership Update, Amendments to Articles of Incorporation or Bylaws; Change in Fiscal Year, Amendments to the Registrant’s Code of Ethics, or Waiver of a Provision of the Code of Ethics, Regulation FD Disclosure, Financial Statements and Exhibits, Other Events