# EDGAR Filing Document

**Accession Number:** 0001069308
**File Stem:** 0001564590-23-001755
**Filing Date:** 2023-2
**Character Count:** 13794
**Document Hash:** 98e2d4dd33004b5d500c2953c61f9c33
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001564590-23-001755.hdr.sgml**: 20230213

**ACCESSION NUMBER**: 0001564590-23-001755

**CONFORMED SUBMISSION TYPE**: 8-K

**PUBLIC DOCUMENT COUNT**: 14

**CONFORMED PERIOD OF REPORT**: 20230213

**ITEM INFORMATION**: Other Events

**ITEM INFORMATION**: Financial Statements and Exhibits

**FILED AS OF DATE**: 20230213

**DATE AS OF CHANGE**: 20230213

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Acer Therapeutics Inc.
- **CENTRAL INDEX KEY:** 0001069308
- **STANDARD INDUSTRIAL CLASSIFICATION:** PHARMACEUTICAL PREPARATIONS [2834]
- **IRS NUMBER:** 320426967
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** 8-K
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-33004
- **FILM NUMBER:** 23615010

**BUSINESS ADDRESS:**
- **STREET 1:** ONE GATEWAY CENTER (300 WASHINGTON ST.)
- **STREET 2:** SUITE 356
- **CITY:** NEWTON
- **STATE:** MA
- **ZIP:** 02458
- **BUSINESS PHONE:** (844) 902-6100

**MAIL ADDRESS:**
- **STREET 1:** ONE GATEWAY CENTER (300 WASHINGTON ST.)
- **STREET 2:** SUITE 356
- **CITY:** NEWTON
- **STATE:** MA
- **ZIP:** 02458

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** Opexa Therapeutics, Inc.
- **DATE OF NAME CHANGE:** 20060616

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** PharmaFrontiers Corp.
- **DATE OF NAME CHANGE:** 20051011

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** PHARMAFRONTIERS CORP
- **DATE OF NAME CHANGE:** 20040816

?xml version="1.0" encoding="utf-8"? acer-8k_20230213.htm

### UNITED STATES

### SECURITIES AND EXCHANGE COMMISSION

#### WASHINGTON, D.C. 20549

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### FORM 8-K

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#### CURRENT REPORT

#### Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

#### Date of Report (date of earliest event reported): February 13, 2023

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### ACER THERAPEUTICS INC.

#### (Exact name of registrant as specified in its charter)

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| | | |
|:---|:---|:---|
| **Delaware** | **001-33004** | **32-0426967** |
| (State or other jurisdiction of<br>incorporation) | (Commission File Number) | (IRS Employer Identification No.) |

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| | |
|:---|:---|
| **One Gateway Center, Suite 356 <br>300 Washington Street**<br> **Newton, Massachusetts** | **02458** |
| (Address of principal executive offices) | (Zip Code) |
| <br> Registrant's telephone number, including area code: **(844) 902-6100** | <br> Registrant's telephone number, including area code: **(844) 902-6100** |
| **N/A** | **N/A** |
| (Former name or former address, if changed since last report) | (Former name or former address, if changed since last report) |

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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)) 

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| | | |
|:---|:---|:---|
| Securities registered pursuant to Section 12(b) of the Act: | Securities registered pursuant to Section 12(b) of the Act: | Securities registered pursuant to Section 12(b) of the Act: |
| <u>Title of Each Class</u> | <u>Trading Symbol</u> | &nbsp;&nbsp;&nbsp;&nbsp;<u>Name of Each Exchange on Which Registered</u> |
| **Common Stock, $0.0001 par value per share** | **ACER** | **The Nasdaq Stock Market LLC** |

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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-2 of the Securities Exchange Act of 1934 (§ 240.12b-2 of 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. ☐

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#### Item 8.01. Other Events.
On February 13, 2023, Acer Therapeutics Inc. issued a press release entitled "Acer Therapeutics Announces Full Enrollment of Phase 2a Trial of ACER-801 (Osanetant) for Treatment of Moderate to Severe Vasomotor Symptoms Associated with Menopause," a copy of which is attached as Exhibit 99.1 hereto and is incorporated herein by reference.

#### Item 9.01. Financial Statements and Exhibits.
(d) Exhibits

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| | |
|:---|:---|
| Exhibit<br> No. | Description |
| 99.1 | [<u>Press release issued by Acer Therapeutics Inc. dated February 13, 2023, entitled</u>](acer-ex991_6.htm) "<u>Acer Therapeutics Announces Full Enrollment of Phase 2a Trial of ACER-801 (Osanetant) for Treatment of Moderate to Severe Vasomotor Symptoms Associated with Menopause.</u>" |
| 104 | Cover page interactive data file (embedded within the inline XBRL document). |

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**SIGNATURES**

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.

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| | | |
|:---|:---|:---|
| Dated: February 13, 2023 | ACER THERAPEUTICS INC. | ACER THERAPEUTICS INC. |
|  | By: | /s/ Harry S. Palmin  |
|  |  | Harry S. Palmin |
|  |  | Chief Financial Officer |

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## Exhibit 99.1

#### Exhibit 99.1

#### Acer Therapeutics Announces Full Enrollment of Phase 2a Trial of ACER-801 (Osanetant) for Treatment of Moderate to Severe Vasomotor Symptoms Associated with Menopause
*Topline trial results expected mid-March 2023*

**NEWTON, MA – February 13, 2023 – Acer Therapeutics Inc. (Nasdaq: ACER), a pharmaceutical company focused on the acquisition, development and commercialization of therapies for serious, rare and life-threatening diseases with significant unmet medical needs, today announced full enrollment of its Phase 2a proof of concept trial of ACER-801 (osanetant), a novel, non-hormonal, neurokinin 3 receptor (NK3R) antagonist, being investigated as a potential treatment option for moderate to severe Vasomotor Symptoms (VMS) associated with menopause. Topline results from this trial are expected in mid-March 2023.** 

The Phase 2a randomized, double-blind, placebo-controlled, dose-ranging trial of ACER-801 is designed to evaluate the safety, pharmacokinetics (PK) and efficacy of ACER-801 in 48 postmenopausal women aged 40-65 who experience moderate to severe hot flashes. Subjects were randomized 1:1:1:1 and receive twice daily doses of either 50mg, 100mg, 200mg of ACER-801 or placebo over a 14-day treatment period, followed by a 14-day safety follow-up assessment. Results from this trial could provide proof of concept data in postmenopausal women and could inform ACER-801 dosing and a development path forward in patients with induced Vasomotor Symptoms (iVMS).

#### About VMS, iVMS and ACER-801
VMS are caused by a disruption in sex hormone signaling in the brain, resulting in menopausal-like symptoms (hot flashes, night sweats, etc.) and most often occur in women during menopausal transition or in menopause (MR-VMS). VMS leads to significant impact on patient quality of life, including sleep deprivation, lack of focus, and anxiety/depression. VMS can also be induced (iVMS) by anti-androgen and anti-estrogen cancer therapies and surgical procedures altering sex hormone production.<sup>1</sup><sup>,</sup><sup>2</sup> VMS are caused by low estrogen levels leading to increased stimulatory signaling of NKB on the Kisspeptin/Neurokinin B/Dynorphin (KNDy) neurons in the hypothalamus. A non-hormonal treatment to manage VMS is needed, especially in patients where estrogen is contraindicated or not well tolerated.

iVMS are well documented with the use of cancer therapies and certain surgical procedures. Symptoms such as hot flashes can appear immediately and be severe. Cancer therapy side effects can lead to treatment non-adherence which increases the mortality risk and/or shortens

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the time to recurrence. Acer also believes a treatment for iVMS is needed to help certain cancer patients to be more likely to start and stay on critical cancer therapies.

ACER-801 (osanetant) is a novel, non-hormonal, NK3R antagonist that could offer a potential treatment option with meaningful improvement of VMS for patients with iVMS by blocking the stimulatory signaling of NKB on the KNDy neurons. Direct human safety evidence is available from 23 completed Phase 1 and 2 studies in which approximately 400 healthy subjects and 820 patients were treated with osanetant for schizophrenia, depression and other indications. Data from these studies indicated no major safety concerns after single-dose and repeat-dose administration.<sup>3</sup> ACER-801 is orally bioavailable<sup>4</sup> and readily crosses the blood-brain barrier.<sup>5</sup> Acer believes that several disorders involving the hypothalamus-pituitary-gonadal axis could be investigated for potential benefit from treatment with an NK3R antagonist.

ACER-801 is an investigational product candidate which has not been approved by FDA or any other regulatory authority. There is no guarantee that this product candidate will receive regulatory authority approval in any territory or become commercially available for any indications.

#### About Acer Therapeutics
Acer is a pharmaceutical company focused on the acquisition, development and commercialization of therapies for serious rare and life-threatening diseases with significant unmet medical needs. In the U.S., OLPRUVA™ (sodium phenylbutyrate) is approved for the treatment of urea cycle disorders (UCDs) involving deficiencies of carbamylphosphate synthetase (CPS), ornithine transcarbamylase (OTC), or argininosuccinic acid synthetase (AS). Acer is also advancing a pipeline of investigational product candidates for rare and life-threatening diseases, including: OLPRUVA™ (sodium phenylbutyrate) for treatment of various disorders, including Maple Syrup Urine Disease (MSUD); ACER-801 (osanetant) for treatment of Vasomotor Symptoms (VMS), Post-traumatic Stress Disorder (PTSD) and prostate cancer; EDSIVO™ (celiprolol) for treatment of vascular Ehlers-Danlos syndrome (vEDS) in patients with a confirmed type III collagen (COL3A1) mutation; and ACER-2820 (emetine), a host-directed therapy against a variety of viruses, including cytomegalovirus, Zika, dengue, Ebola and COVID-19. For more information, visit www.acertx.com.

#### References
1. Kotsopoulos J, Huzarski T, Gronwald J, Moller P, Lynch HT, Neuhausen SL, et al. Hormone replacement therapy after menopause and risk of breast cancer in BRCA1 mutation carriers: a case-control study. Breast Cancer Research and Treatment 2016;155(2):365–73.

2. Guidozzi F. Hormone therapy after prophylactic risk-reducing bilateral salpingo-oophorectomy in women who have BRCA gene mutation. Climacteric 2016;19(5): 419–22.

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3. Meltzer H, et al. Placebo-controlled evaluation of four novel compounds for the treatment of schizophrenia and schizoaffective disorder. June 2004; 161(6):975-84.

4. Single and Repeated Ascending Oral Dose Tolerability Study of SR142801 in Healthy Male Subjects. Sanofi Clinical Study Report February 2001.

5. Gueudet C, et al. Blockade of neurokinin3 receptors antagonizes drug-induced population response and depolarization block of midbrain dopamine neurons in guinea pigs. Synapse. 1999 Jul;33(1):71-9.

#### Acer Forward-Looking Statements
This press release contains "forward-looking statements" that involve substantial risks and uncertainties for purposes of the safe harbor provided by the Private Securities Litigation Reform Act of 1995. All statements, other than statements of historical facts, included in this press release are forward-looking statements. Examples of such statements include, but are not limited to, statements about the continued development of ACER-801 for treatment of iVMS and our expected 2023 milestones. Our pipeline products (including ACER-801) are under investigation and their safety and efficacy have not been established and there is no guarantee that any of our investigational products in development will receive health authority approval or become commercially available for the uses being investigated. We may not actually achieve the plans, carry out the intentions or meet the expectations or projections disclosed in the forward-looking statements and you should not place undue reliance on these forward-looking statements. Such statements are based on management's current expectations and involve risks and uncertainties. Actual results and performance could differ materially from those projected in the forward-looking statements as a result of many factors, including, without limitation, the availability of financing to fund our pipeline product development programs and general corporate operations as well as risks related to drug development and the regulatory approval process, including the timing and requirements of regulatory actions. We disclaim any intent or obligation to update these forward-looking statements to reflect events or circumstances that exist after the date on which they were made. You should review additional disclosures we make in our filings with the Securities and Exchange Commission, including our Annual Report on Form 10-K and Quarterly Reports on Form 10-Q. You may access these documents for no charge at http://www.sec.gov.

#### Corporate and IR Contact
Jim DeNike

Acer Therapeutics Inc.

jdenike@acertx.com

+1-844-902-6100

Nick Colangelo

Gilmartin Group

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nick@gilmartinIR.com

+1-332-895-3226