POWER OF ATTORNEY

            We, the undersigned, under the authority granted to each of us to
sign jointly on behalf of Novartis AG, hereby grant powers to Simon Zivi,
Laurieann Chaikowsky, Michael Jones, David Middleton, Bartosz Dzikowski,
Reinhard Ambros and Campbell Murray and constitute and appoint any two of them
jointly as our true and lawful attorneys and representatives and to act on our
behalf and to sign filings to be made with the U.S. Securities and Exchange
Commission (the "SEC") relating to the shares of Aerpio Therapeutics, Inc. held
by Novartis Bioventures Ltd, an indirect subsidiary of Novartis AG, as required
by the SEC (the "SEC Filings"), and to undertake and carry out all tasks and
formalities on our behalf which may be required in connection with giving effect
to the SEC Filings.

            We, the undersigned, undertake to ratify and confirm whatever our
true and lawful attorneys do or purport to do in good faith in the exercise of
any power conferred by this Power of Attorney.

            We, the undersigned, declare that a person who deals with our true
and lawful attorneys in good faith may accept a written statement signed by such
attorneys to the effect that this Power of Attorney has not been revoked as
conclusive evidence of that fact.

            The authority granted by this Power of Attorney shall expire
immediately after the date on which the SEC Filings are no longer required.

            IN WITNESS WHEREOF, this Power of Attorney is duly signed on this 17
day of March 2017.

                                            Novartis AG


                                            By:   /s/ Christian Rehm
                                               --------------------------------
                                            Name: Christian Rehm
                                            Title: Authorized Signatory


                                            By:   /s/ Katja Roth Pellanda
                                               --------------------------------
                                            Name: Katja Roth Pellanda
                                            Title: Authorized Signatory