8-K

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): April 27, 2023

ACER THERAPEUTICS INC.

(Exact name of registrant as specified in its charter)

Delaware 001-33004 32-0426967

(State or other jurisdiction

of incorporation)

(Commission

File Number)

(IRS Employer
Identification No.)

One Gateway Center, Suite 356
300 Washington Street

Newton, Massachusetts

02458
(Address of principal executive offices) (Zip Code)

Registrant's telephone number, including area code: (844)902-6100

N/A

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

Check the appropriate box below if the Form 8-Kfiling 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-12under the Exchange Act (17 CFR 240.14a-12)

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

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

Securities registered pursuant to Section 12(b) of the Act:

Title of Each Class

Trading
Symbol

Name of Each Exchange

on Which Registered

Common Stock, $0.0001 par value per share ACER The Nasdaq Stock Market LLC

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§ 230.405 of this chapter) or Rule 12b-2of the Securities Exchange Act of 1934 (§ 240.12b-2of this chapter).

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 8.01.

Other Events.

On April 27, 2023, Acer Therapeutics Inc. (the "Company") filed a prospectus supplement relating to the offer and sale from time to time of shares (the "Shares") of its common stock, $0.0001 par value per share, with an aggregate offering price of up to $4,100,000 pursuant to the Company's existing at-the-market(ATM) facility and Amended and Restated Sales Agreement, dated March 18, 2020, among the Company, JonesTrading Institutional Services LLC and Roth Capital Partners, LLC. A copy of the opinion of Pillsbury Winthrop Shaw Pittman LLP relating to the legality of the issuance and sale of the Shares is attached as Exhibit 5.1 hereto.

This Current Report on Form 8-Kshall not constitute an offer to sell or the solicitation of an offer to buy any Shares, nor shall there be any sale of Shares in any state or other jurisdiction in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such state or other jurisdiction.

Item 9.01.

Financial Statements and Exhibits.

(d) Exhibits

Exhibit
No.

Description

5.1 Opinion of Pillsbury Winthrop Shaw Pittman LLP.
23.1 Consent of Pillsbury Winthrop Shaw Pittman LLP (included in Exhibit 5.1).
104 Cover Page Interactive Data File (embedded within the Inline XBRL document).

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SIGNATURE

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, thereunto duly authorized.

Dated: April 27, 2023 ACER THERAPEUTICS INC.
By:

/s/ Harry S. Palmin

Harry S. Palmin
Chief Financial Officer

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Acer Therapeutics Inc. published this content on 27 April 2023 and is solely responsible for the information contained therein. Distributed by Public, unedited and unaltered, on 27 April 2023 10:26:00 UTC.