Filed pursuant to Rule 424(b)(3)

Registration No. 333-217320

PROSPECTUS SUPPLEMENT NO. 13

(To Prospectus Dated June 23, 2017)

Aerpio Pharmaceuticals, Inc.

27,367,117 Shares

Common Stock

This prospectus supplement no. 13 supplements the prospectus dated June 23, 2017, relating to the offering and resale of up to 27,367,117 shares of our common stock, par value $0.0001 per share, that were privately issued to selling stockholders in connection with a merger transaction and a private placement.

This prospectus supplement incorporates into our prospectus the information contained in our attached current report on Form 8-K, which was filed with the Securities and Exchange Commission on June 21, 2018.

You should read this prospectus supplement in conjunction with the prospectus, including any supplements and amendments thereto. This prospectus supplement is qualified by reference to the prospectus except to the extent that the information in the prospectus supplement supersedes the information contained in the prospectus.

This prospectus supplement is not complete without, and may not be delivered or utilized except in connection with, the prospectus, including any supplements and amendments thereto.

Our common stock is presently quoted for trading on the OTC Markets – OTCQB tier, or OTCQB, under the symbol “ARPO.” On June 20, 2018, the closing price of our common stock, as quoted on the OTCQB, was $4.00 per share.

You should carefully consider matters discussed under the caption “Risk Factors” beginning on page 9 of the prospectus.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus supplement or the prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

The date of this prospectus supplement is June 22, 2018.

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d)

of The Securities Exchange Act of 1934

Date of Report (Date of Earliest Event Reported): June 20, 2018

AERPIO PHARMACEUTICALS, INC.

(Exact name of registrant as specified in its charter)

Delaware	000-53057	61-1547850
(State or other jurisdiction of incorporation)	(Commission File Number)	(I.R.S. Employer Identification No.)

9987 Carver Road Cincinnati, OH	45242
(Address of principal executive offices)	(Zip Code)

Registrant’s telephone number, including area code (513) 985-1920

Not Applicable

(Former name or former address, if changed since last report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 or Rule 12b-2 of the Securities Exchange Act of 1934.

Emerging growth company  ☒

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.  ☒

Item 5.07. Submission of Matters to a Vote of Security Holders.

The Company held its Annual Meeting of Stockholders (the “Annual Meeting”) on June 20, 2018. As of April 21, 2018, the record date for the Annual Meeting, there were 27,146,099 outstanding shares of the Company’s common stock. The Company’s stockholders voted on the following matters, which are described in detail in the Company’s Definitive Proxy Statement filed with the U.S. Securities and Exchange Commission (“SEC”) on May 15, 2018: (i) to elect Cheryl Cohen, Caley Castelein and Stephen Hoffman as Class I directors of the Company to each serve for a three-year term expiring at the Company’s annual meeting of stockholders in 2021 and until their successors have been elected and qualified , subject to their earlier resignation or removal (“Proposal 1”); (ii) to ratify the appointment of Ernst & Young, LLP as our independent registered public accounting firm for the fiscal year ending December 31, 2018 (“Proposal 2”); and (iii) to approve the Amended and Restated 2017 Employee Stock Purchase Plan (“Proposal 3”).

The Company’s stockholders approved the Class I director nominees recommended for election in Proposal 1 at the Annual Meeting. The Company’s stockholders voted for Class I directors as follows:

Class I Director Nominee	For	Withhold	Broker Non-Votes
Cheryl Cohen	18,448,242	10,050	995,204
Caley Castelein	18,447,742	10,550	995,204
Stephen Hoffman	18,446,742	11,550	995,204

The Company’s stockholders approved Proposal 2. The votes cast at the Annual Meeting were as follows:

For	Against	Abstain
19,429,410	4,086	20,000

The Company’s stockholders approved Proposal 3. The votes cast at the Annual Meeting were as follows:

For	Against	Abstain
18,348,242	30,050	80,000

No other matters were submitted to or voted on by the Company’s stockholders at the Annual Meeting.

*     *      *

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

Date: June 22, 2018	AERPIO PHARMACEUTICALS, INC.
	By:	/s/ Stephen Hoffman
		Stephen Hoffman Chief Executive Officer