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): December 30, 2022

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-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))

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-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. ☐

Item 1.01. Entry into a Material Definitive Agreement.

On December 30, 2022, Acer Therapeutics Inc. (the “Company”) entered into an extension agreement (the “Extension Agreement”) with MAM Aardvark, LLC (“Marathon”) and the lenders party thereto (the “Lenders”), which amends that certain Credit Agreement, dated as of March 4, 2022, previously entered into by the parties (the “Marathon Credit Agreement”), as summarized in the Company’s Current Report 8-K filed on March 7, 2022. The effect of the Extension Agreement is (i) to extend the last date for the Company to request funding by the Lenders of the Term Loan Commitment (as defined in the Marathon Credit Agreement) of $42.5 million, from December 31, 2022 to January 16, 2023, and (ii) to extend the last date upon which the Company may pay the Term Loan Commitment fee (as set forth in Section 2.7(b) of the Marathon Credit Agreement), from 12 business days from approval by the U.S. Food and Drug Administration of OLPRUVA™ (sodium phenylbutyrate) for oral suspension in the U.S. for the treatment of certain patients living with urea cycle disorders involving deficiencies of carbamylphosphate synthetase, ornithine transcarbamylase, or argininosuccinic acid synthetase, which the Company previously announced on December 27, 2022, to 12 business days from January 16, 2023. These extensions are intended to provide the Company and Marathon additional time to conclude discussions presently underway, to determine whether they have an agreement to further amend or modify the existing terms and conditions of the Marathon Credit Agreement and/or related agreements.

The Extension Agreement does not amend or apply to the SWK Credit Agreement entered into between the Company and SWK Funding LLC (“SWK”) on March 4, 2022, by which SWK holds a first priority security interest in all of the Company’s assets.

The foregoing descriptions of the Extension Agreement and the Marathon Credit Agreement do not purport to be complete and are subject to and qualified in their entirety by reference to each of the Extension Agreement, a copy of which is attached hereto as Exhibit 10.1 and is incorporated herein by reference, and the Marathon Credit Agreement which is Exhibit 10.2 hereto and is incorporated herein by reference.

Forward-Looking Statements

This Item 1.01 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 Item 1.01 are forward-looking statements. Such statements include statements that the extensions are intended to provide the Company and Marathon additional time to conclude discussions and make determinations regarding the terms and conditions of the Marathon Credit Agreement and/or related agreements. There can be no assurance that the Company and Marathon will reach a definitive written agreement on any terms, or at all, before or after the extended period described above; or that any such amended or revised terms, if agreed, prove to be more favorable to the Company, compared to the terms of the Marathon Credit Agreement as presently structured. In addition, there can be no assurance of the Company’s ability to close upon and obtain the proceeds of the Term Loan Commitment set forth in the Marathon Credit Agreement or any other financing arrangements, or to satisfy the ongoing conditions and requirements for maintaining any current or future financing facilities.

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 Company’s actual operating and capital requirements. The Company disclaims 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. Interested parties should review additional disclosures the Company makes in its filings with the Securities and Exchange Commission, including the Company’s Annual Report on Form 10-K and Quarterly Reports on Form 10-Q. These documents may be accessed for no charge at http://www.sec.gov.

Item 7.01.Regulation FD Disclosure.

The Company has updated its Corporate Presentation that will be available on the Investor Relations page of the Company’s website at https://acertx.com/investor-relations and used at meetings held by the Company with investors and others.  A copy of the updated Corporate Presentation is furnished as Exhibit 99.1 to this Current Report on Form 8-K and is incorporated herein by reference. The Company does not undertake to update this Corporate Presentation except as required by law.

The information in Item 7.01 of this Current Report on Form 8-K, including the Corporate Presentation furnished as Exhibit 99.1, shall not be deemed to be filed for purposes of Section 18 of the Securities Exchange Act of 1934 (the “Exchange Act”), or otherwise subject to the liability of that section, and shall not be incorporated by reference into any registration statement or other document filed under the Securities Act of 1933 or the Exchange Act, except as shall be expressly set forth by specific reference in such filing.

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Item 9.01.Financial Statements and Exhibits.

(d)  Exhibits

Exhibit No.	Description
10.1	Extension Agreement, dated as of December 30, 2022, among Acer Therapeutics Inc., MAM Aardvark, LLC as administrative and collateral agent for the lenders, and the lenders party thereto.
10.2	Credit Agreement dated March 4, 2022, among Acer Therapeutics Inc., the lenders party thereto and MAM Aardvark, LLC, as the agent, sole lead arranger and sole bookrunner (incorporated by reference to Exhibit 10.6 to the Registrant’s Current Report on Form 8-K filed on March 7, 2022).
99.1	Acer Therapeutics Inc. Corporate Presentation, January 2023.
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.

Dated: January 3, 2023	ACER THERAPEUTICS INC.
	By:	/s/ Harry S. Palmin
		Harry S. Palmin
		Chief Financial Officer

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EX-10.1

Exhibit 10.1

EXTENSION AGREEMENT

This Extension Agreement (this “Extension Agreement”) dated as of December 30, 2022, is among Acer Therapeutics Inc., a Delaware corporation (“Borrower”), MAM Aardvark, LLC, not individually, but solely in its capacity as administrative and collateral agent for the Lenders (the “Agent”) and the Lenders party hereto.

WHEREAS, the Borrower, the Lenders and the Agent are party to that certain Credit Agreement, dated as of March 4, 2022 (the “Credit Agreement”), pursuant to which the Lenders agreed to make loans to the Borrower on the terms set forth therein;

WHEREAS, the Borrower has requested that the Agent and the Lenders make a limited amendment to the Credit Agreement, and the Agent and the Lenders are willing to make such amendment to the Credit Agreement on the terms and subject to the conditions set forth herein.

NOW, THEREFORE, in consideration of the mutual agreements herein contained, and for other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, the parties hereto agree as follows:

1.Definitions; Loan Document.  Capitalized terms used herein without definition shall have the meanings assigned to such terms in the Credit Agreement. This Extension Agreement shall constitute a Loan Document for all purposes of the Credit Agreement and the other Loan Documents.

2.Amendment. Upon the effectiveness of this Extension Agreement, the Credit Agreement is hereby amended as follows:

(a)Section 2.2.1 of the Credit Agreement is hereby amended by replacing the reference to “December 31, 2022” in such section with “January 16, 2023”.

(b)Section 2.7(b) of the Credit Agreement is hereby amended to add the following at the end of that section: “; provided that in any case, the Subsequent Commitment Fee Trigger Date shall not be earlier than twelve (12) Business Days following January 16, 2023.”

3.Conditions to Effectiveness.  This Extension Agreement shall become effective on the date on which the Borrower, the Agent and the Lenders receive counterpart signatures to this Extension Agreement duly executed and delivered by the Loan Parties, the Agent and each Lender.

4.No Implied Amendment or Waiver.  This Extension Agreement is limited to the matter specifically set forth herein and shall not, by implication or otherwise, limit, impair, constitute a waiver of or otherwise affect any rights or remedies of the Borrower, the Agent or any Lender under the Credit Agreement and Loan Documents, or alter, modify, amend or in any way affect any of the other terms, obligations or covenants contained in the Credit Agreement and Loan Documents, all of which shall continue in full force and effect. Nothing in this Extension Agreement shall be construed to imply any willingness on the part of the Borrower, the Agent or any Lender to agree to or grant any similar or future amendment, consent or waiver of any of the terms and conditions of the Credit Agreement or any Loan Document. Each of the Administrative Agent, each Lender, and the Borrower hereby reserves all of its rights, remedies and defenses available under the Credit Agreement, the Loan Documents and applicable law, including without limitation as a result of any past, continuing or future Defaults, Events of Default, breaches or other defaults.  Neither the Borrower, the Administrative Agent nor the Lenders have waived, and are not hereby waiving, any Defaults, Events of Default, breaches or other defaults which may have occurred prior to the date hereof or which may be continuing on the date hereof, or any of its rights or

remedies, and neither the Borrower nor the Lenders have agreed to forbear with respect to any of their rights and remedies concerning any Default, Event of Default, breach or other default which may have occurred prior to the date hereof or which may be continuing on the date hereof.  Nothing contained herein, and no delay on the part of the Borrower, the Administrative Agent or the Lenders in exercising any such rights or remedies arising from this Extension Agreement, shall be construed as a waiver of any such rights or remedies.

5.Expenses.  The Loan Parties agree to pay all reasonable out-of-pocket and documented costs and expenses of the Agent and the Lenders in connection with this Extension Agreement (including, without limitation, the reasonable fees and out-of-pocket expenses of counsel to the Agent and the Lenders incurred in connection with the negotiation, preparation, execution and delivery of this Extension Agreement and the other Loan Documents).

6.Counterparts.This Extension Agreement may be executed in any number of counterparts and by different parties on separate counterparts, each of which, when executed and delivered, is an original, and all taken together, constitute one agreement.  Executed copies of the signature pages of this Extension Agreement sent by facsimile or transmitted electronically shall be treated as originals, fully binding and with full legal force and effect, and the parties waive any rights they may have to object to such treatment.  

7.Governing Law.  This EXTENSION AGREEMENT SHALL BE A CONTRACT MADE UNDER AND GOVERNED BY THE INTERNAL LAWS OF THE STATE OF NEW YORK APPLICABLE TO CONTRACTS MADE AND TO BE PERFORMED ENTIRELY WITHIN SUCH STATE, WITHOUT REGARD TO CONFLICT OF LAWS PRINCIPLES (OTHER THAN SECTION 5-1401 OF THE NEW YORK GENERAL OBLIGATIONS LAW).

[Remainder of Page Intentionally Left Blank]

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IN WITNESS WHEREOF, the parties hereto have caused this Extension Agreement to be duly executed as of the date first written above.

Borrower:

Acer Therapeutics inc.

By_/s/ Chris Schelling____________________

Name: Chris Schelling

Title: CEO & Founder

[Signature Page to Extension Agreement]

AGENT AND LENDER:

MAM Aardvark, LLC

By_/s/ Louis Hanover_____________________

Name: Louis Hanover

Title: Authorized Signatory

Lender:

Marathon Healthcare Finance Fund, L.P.

By_/s/ Louis Hanover_____________________

Name: Louis Hanover

Title: Authorized Signatory

[Signature Page to Extension Agreement]

EX-99.1

Corporate Presentation January 2023 Exhibit 99.1

Forward-looking statements This presentation 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 presentation regarding strategy, future operations, timelines for clinical study enrollment or regulatory actions, or otherwise, future financial position, future revenues, projected expenses, regulatory submissions, actions or approvals, cash position, liquidity, prospects, plans and objectives of management are forward-looking statements. Examples of such statements include, but are not limited to, statements relating to the potential for our investigational product candidates to safely and effectively treat diseases and to be approved for marketing; our ability to close upon and obtain the proceeds of any identified financing arrangements as well as to satisfy the ongoing conditions and requirements for maintaining the financing facilities and avoiding default or an accelerated payment requirement; the commercial or market opportunity and potential of OLPRUVA™ for the treatment of patients with UCDs, including the opportunity for approval in territories outside of the United States; the commercial or market opportunity of any of our product candidates in any target indication and any territory; our ability, in addition to the currently identified financings, to secure the additional capital necessary to fund our various product candidate development programs; the adequacy of our capital to support our future operations and our ability to successfully fund, initiate and complete clinical trials and regulatory submissions for OLPRUVA™ in MSUD, ACER-801, EDSIVO™ or our other investigational product candidates; the ability to protect our intellectual property rights; our strategy and business focus; and the development, expected timeline and commercial potential of any of our product candidates. Our pipeline product candidates are under investigation, 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, risks and uncertainties associated with the ability to project future cash utilization and reserves needed for contingent future liabilities and business operations, the ability to launch successfully and sustain commercial viability of OLPRUVA™ for the treatment of patients with UCDs in the United States, the availability of sufficient resources to fund our various product candidate development programs and to meet our business objectives and operational requirements, the fact that the results of earlier studies and trials may not be predictive of future clinical trial results, the protection and market exclusivity provided by our intellectual property, risks related to the drug development and the regulatory approval process, including the timing and requirements of regulatory actions, and the impact of competitive products and technological changes. 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.

To provide transformative treatments with a human touch to underserved or overlooked patients with rare and life-threatening diseases We identify and develop treatments where science can be applied in new ways for use in diseases with high unmet need To develop treatments quickly and more efficiently and deliver them to patients as fast as possible The Acer story Our Mission Our Difference Our Goal Acer is a pharmaceutical company that acquires, develops and commercializes therapies for serious rare and life-threatening diseases with significant unmet medical needs

Acer Management team Chris schelling Chief Executive officer & Founder Adrian quartel, md Chief medical officer Harry palmin Chief financial officer Matt seibt Chief commercial officer Bernie paul Chief people officer Don joseph, Jd Chief legal officer John klopp Chief technical officer Tanya hayden Chief operating officer Jeff davis Chief business officer

pipeline $ Subject to additional capital 1 OLPRUVA™ (sodium phenylbutyrate) for oral suspension approved in the U.S. for the treatment of certain patients living with urea cycle disorders (UCDs) involving deficiencies of carbamylphosphate synthetase (CPS), ornithine transcarbamylase (OTC), or argininosuccinic acid synthetase (AS) 2 University of North Carolina investigator-sponsored trial

Full Prescribing Information: https://www.acertx.com/OLPRUVA/PI.pdf OLPRUVATM (sodium phenylbutyrate) for oral suspension

UCDs: DISEASE Overview Urea Cycle Disorders (UCDs) are a group of rare, genetic disorders caused by mutations that result in a deficiency of one of the six enzymes or two transporters of the urea cycle These enzymes are responsible for removing ammonia from the bloodstream Reproduced from:   http://upload.wikimedia.org/wikipedia/commons/7/76/Symptoms_of_hyperammonemia.svg. Elevated ammonia levels in both symptomatic and asymptomatic patients can be neurotoxic leading to neurocognitive damage, among other symptoms Cytoplasm Mitochondrion HCO3+NH4+2ATP CPS1 Glutamate NAGS N-acetylglutamate (CPS1 cofactor) Carbamyl Phosphate OTC Carbamyl Aspartate Orotic Acid Ornithine Urea ARG H2O Arginine Citrulline ASS Argininosuccinate ASL Fumarate Ammonia enters the liver A healthy urea cycle converts ammonia into urea, which is excreted from the body NAGS = N-acetylglutamate synthase CPS1 = Carbamoyl phosphate synthase OTC = Ornithine transcarbamylase AS = Argininosuccinate synthase AL = Argininosuccinate lyase ARG = Arginase Liver cell With a Urea Cycle Disorder (UCD), ammonia is not converted to urea, and ammonia builds up in the body. H N Symptoms of Hyperammonemia General – Growth retardation – Hypothermia Central – Combativeness – Lethargy – Coma Eyes – Papilledema Pulmonary – Shortness of breath Liver – Enlarge-ment Muscular/Neurologic – Poor coordination – Dysdiadochokinesia – Hypotonia or hypertonia – Ataxia – Tremor – Seizures – Decorticate or decerebrate posturing

UCDs: Mechanism of action Berry S, et al. Molecular Genetics and Metabolism 125 (2018) 251–257. NH4+ α-Ketoglutarate Glutamate Glutamine PAGN Nitrogen Binding Agents β-oxidation PAA Urine Excretion Fig. 1. Metabolizing pathway and mechanism of action of GPB. GPB (glycerol phenylbutyrate); PAA (phenylacetic acid); PBA (phenylbutyric acid); PAGN (phenylacetylglutamine).

NOVEL Formulation OLPRUVA™ is a proprietary and novel formulation of NaPB powder that has shown bioequivalence to existing NaPB powder but with a pH-sensitive polymer coating that is designed to minimize dissolution of the coating for up to 5 minutes after preparation1 Polymer Coat (inactive pH-sensitive polymer) Designed to minimize dissolution of the coating over 5 minutes after preparation Drug Layer (NaPB) Delivers the proven ammonia control of NaPB powder1 Seal Coat (inactive ingredients) Seed Core (inactive core) 1 Acer Therapeutics. Data on File. 2021.

Nitrogen Scavenger Differentiation1 1 No head-to-head studies have been conducted with OLPRUVA™ and any of the other products named, other than the bioequivalence study undertaken for 505(b)(2) pathway RAVICTI®, BUPHENYL®, PHEBURANE® information sourced from prescribing information OLPRUVA™, RAVICTI®, BUPHENYL®, and PHEBURANE® are the registered trademarks of their respective owners

Commercial Strategy Significant unmet need and desire for new treatment options OLPRUVA™ is differentiated, dual coated, packaged in portable single dose envelopes Robust patient services program to support patients & caregivers Customized exclusive pharmacy approach to facilitate patient access to care Best in class team of rare disease professionals with deep relationships in UCD centers Commercial Launch Strategy = Positive Patient Experience + Exceptional Support NAVIGATOR by acertherapeutics

DISRUPTING AN ESTABLISHED UCD MARKET in U.S. 1 https://www.drugs.com/slideshow/top-10-most-expensive-drugs-1274 2 HealthVerity Payer claims data analysis 3 https://ir.horizontherapeutics.com/static-files/47f395cb-4d8e-47a7-ba20-2f3c6f433e62; Represent North American sales

Intellectual property (IP) Issued patents: US Patent 11,154,521 covering claims re: formulation compositions of matter (expires in 2036) US Patent 11,202,767 covering claims re: certain methods of use (expires in 2036) US Patent 10,092,532 covering claims re: methods of modulation of branched chain acids Licensed from Baylor College of Medicine relating to MSUD Notice of Allowance: US patent application No. 16,624,834 for claims re: a kit comprising a combination therapeutic product composed of sodium phenylbutyrate or glycerol phenylbutyrate and sodium benzoate Licensed from Baylor College of Medicine Continuing to pursue new patents and exclusivity possibilities, based on development plans and product attributes

Acer intends to explore additional lifecycle opportunities for OLPRUVA™ (sodium phenylbutyrate) in various disorders where proof of concept data exists: Maple Syrup Urine Disease (MSUD) Pyruvate Dehydrogenase Complex Deficiency (PCDC) Rare pediatric epilepsies Various liver disorders Lifecycle Opportunities

A novel, non-hormonal, Neurokinin 3 receptor (NK3R) antagonist Acute Stress & PTSD Induced Vasomotor Symptoms Prostate Cancer ACER-801 (osanetant)

Peripheral Vasodilation (Hot Flash, VMS) Targeting Key Pathways of NKB/NK3R Signaling PTSD / Fear Consolidation Vasomotor Symptoms Estrogen - Low Estrogen/High progesterone dysregulates NKB signaling in the hypothalamus leading to VMS Blocking NK3R prevents this dysregulation - + - + NK3R over-expression in the amygdala increases fear sensation signaling to dACC and hippocampus. This dysregulation causes inappropriate and exaggerated fear consolidation and PTSD Progesterone + Hypothalamus / KNDy neuron + ACER-802-201 Study NK3r ER PR NKB Amygdala + NK3r dorsal anterior cingulate cortex (dACC) and hippocampus medial prefrontal cortex Inappropriate Fear Consolidation OASIS Study NKB

VMS and ivms 50% of women during menopause transition experience mod-severe hot flashes iVMS is a prevalent side-effect of various cancer treatments, with 60-80% reporting hot flashes1,2,3 EPIDEMIOLOGY Moderate to Severe VMS Eligible Patients: 5.3M-7.1M in US (moderate-severe)2 iVMS Eligible Patients: 47,000 BRCA+ women in US that had PBSO2 120,000 women in US w/HR+ breast cancer receiving Tamoxifen2 1 Johnson L, et al. American Society for Reproductive Medicine, 2014 Vol 102 No. 3, Supplement, e249 2 Nichols H, et al., JNCI J Natl Cancer Inst, 2015, 1–8 3 Challapalli A, et al., Clinical and Translational Radiation Oncology 10 (2018) 29–35

MOA: Neurokinin-B (NKB) and NK3 Receptor Neurokinin B (NKB;TAC2 gene) is stimulatory molecule that activates the neurokinin 3 receptor (NK3R) found in the arcuate nucleus (ARC) of the hypothalamus and the central amygdala regions of the brain The hypothalamus controls body homeostasis and the kisspeptin/ neurokinin B/dynorphin (KNDy) neurons in the ARC are responsible for thermoregulation The central amygdala is critical for the perception of emotions, including fear memory consolidation Thermoregulation (hot flashes) is mediated by a balance between estrogen (inhibitory/protective) and neurokinin B (stimulatory) signaling in KNDy neurons Hypothalamus Amygdala Dyn NKB ERα PF + - POA/Infundibular nucleus Kiss1 GnRH neurone ME Pituitary LH/FSH Gonads Sex Steroids

Three different NK3R antagonists have been associated with reductions of hot flashes in clinical studies in menopausal related vasomotor symptoms (MR-VMS) MLE4901 (Millendo), fezolinetant (Astellas) and NT 814 (KaNDy Therapeutics) Effects appear similar across the class, and similar to estrogen, but with more rapid onset of action– Reductions in both hot flash frequency and severity observed by day 3 in MLE4901 treated patients vs. placebo6 1: 4-week study; 40mg BID. Prague et al., 2017 2: 4-week study; 90mg BID. Depypereet al., 2019 3: 12-week study; 30mg QD. Fraser et al., 2020 4: 2-week study; 150mg QD. Trower et al., 2020 5: 4-week study; low dose (all doses similar). Utian, 2001 6: Prague et al., 2018 % Change in Hot Flash Frequency From Baseline Across Individual Studies of NK3R Antagonists Vms reduction across nk3r antagonist class MLE4901Phase 2 (4 weeks) [1] Fezolinetant Phase 2a (4 weeks) [2] Fezolinetant Phase 2b (12 wks) [3] NT-814 Phase 2a (2 weeks) [4] CEE/MPA (4 weeks) [5] Placebo Active 0% -10% -20% -30% -40% -50% -60% -70% -80% -90% -100%

Induced Vasomotor Symptoms (iVMS) Women with HR+ Breast Cancer (CaB) receiving Tamoxifen 84% of women experienced hot flashes3 80% experienced night sweats 60% experienced severe symptoms Symptoms persisted throughout 5 years of treatment and were mainly attributed to tamoxifen After 4.5 years, 46% of women had discontinued tamoxifen4 Women who are BRCA+ and have prophylactic bilateral salpingo-oophorectomy (PBSO) 67% of women have symptoms of menopause such as hot flashes1 Up to 35% complain of “extremely bothersome” symptoms up to two years after their surgery2 Men with Prostate Cancer (CaP) receiving Leuprolide 80% of men experience hot flashes5 15-27% of patients consider hot flashes the most distressing side effect 30-40% experienced moderate-to-severe symptoms 20% discontinued or disrupted treatment 1 L. Johnson, et al. American Society for Reproductive Medicine, 2014 Vol 102 No. 3, Supplement, e249. 2 Griffiths, E, et al: The Obstetrician & Gynaecologist, 2005: 7:23-27. 3 Moon, Z. et al., JOURNAL OF PSYCHOSOMATIC OBSTETRICS & GYNECOLOGY, 2017 VOL. 38, NO. 3, 226–235 4 Nichols, H, et al., JNCI J Natl Cancer Inst, 2015, 1–8. 5 Challapalli, A, et al., Clinical and Translational Radiation Oncology 10 (2018) 29–35.

iVMS: UNMET Need

Ongoing ACER-801-201 Study: Topline Results Expected Q1 2023$ VMS: phase 2 trial $ Subject to additional capital

A novel, non-hormonal, Neurokinin 3 receptor (NK3R) antagonist Acute Stress & PTSD Induced Vasomotor Symptoms ACER-801 (osanetant)

acute stress & ptsd EPIDEMIOLOGY PTSD Prevalence: ~12 million adults in US3 ~60% of men and 50% of women experience at least 1 trauma in their lifetime Up to 20% of those who experienced at least one traumatic event will develop PTSD4 Emergency Dept. Visits: ~1/3 of ED visits are for trauma exposure4 1 Andero R, Dias BG, Ressler KJ. A role for Tac2, NkB, and Nk3 receptor in normal and dysregulated fear memory consolidation. Neuron. 2014;83(2):444-454 2 Andero R, Daniel S, Guo JD, et al. Amygdala-Dependent Molecular Mechanisms of the Tac2 Pathway in Fear Learning. Neuropsychopharmacology. 2016;41(11):2714-2722 3 National Center for PTSD. How Common is PTSD in Adults? 4 Sidran Institute. Traumatic Stress Education & Advocacy Fact Sheet.

Development of ASD & PTSD 40-50 million people per experience A traumatic event1,2 ASD w/o PTSD 1 McLean et. al., The AURORA Study: a longitudinal, multimodal library of brain biology and function after traumatic stress exposure. Mol Psychiatry. 2020 Feb;25(2):283-296 2 National Hospital Ambulatory Medical Care Survey: 2011 emergency department summary tables. 2011. (Accessed October 28, 2015, at http://www.cdc.gov/nchs/data/ahcd/nhamcs_emergency/2011_ed_web_tables.pdf.) 3 https://www.ptsd.va.gov/understand/common/common_adults.asp Traumatic event

MOA: Osanetant can block Fear Consolidation NKR activation is required for normal consolidation of fear memory formation Increased expression of the Tac2 gene (NKB peptide) and activation of NK3R involved in stress sensitization and over consolidation of fear Genetic silencing of Tac2-expressing neurons impairs fear consolidation and blockade of this pathway Osanetant targets the NK3R in the amygdala and in vivo data has shown impairment of fear memory consolidation Source: Andero, et al. Neuron 83, 444-454, July 16, 2014. Tac2 detected by immunocytochemistry in mouse amygdala cell culture NkB in the Amygdala NkB ng/mL Home Cage Fear Conditioning 0.0 0.2 0.4 0.6 0.8 1.0 24hrs after receiving Vehicle or Osanetant Fear conditioning (FC) (5 CS) Fear expression (15 CS) % Freezing to CS 20 25 30 35 40 45 30min before FC 10min after FC 1hr after FC 4hrs after FC

PTSD: PARTNERSHIPS Osanetant After Stress to Increase Recovery Success (OASIS) Trial Objective: examine the safety / efficacy of ACER-801 to reduce acute stress response symptoms, PTSD symptoms & behavioral changes among emergency department patients after a motor vehicle collision Trial to enroll 180 subjects who will be randomized in the emergency department Patients to receive a low or high dose of ACER-801 or placebo and be discharged with a two-week supply of study drug Emory Agreement Exclusive WW license to US patents and applications covering certain methods of treating or preventing PTSD with osanetant Acer paid Emory a fee in exchange for exclusive license and will pay Emory certain development milestones and low single digit royalties on future product sales in these indications University of North Carolina Partnership Leading academic institution in trauma recovery UNC awarded $3 million grant from Department of Defense to investigate potential of ACER-801 (osanetant) to reduce frequency and severity of acute stress disorder and PTSD UNC to conduct investigator-led trial in Q4

PTSD: phase 2 trial Osanetant After Stress to Increase recovery Success (OASIS Study) (N=180) Low Dose ACER-801 N=60 High Dose ACER-801 N=60 Placebo N=60 Presentation to Emergency Department within 24 Hours of MVC Consent/Enrollment Procedures Baseline Surveys: ASD, PTSD, Pain, NeuroCog Enrich via PTS Prediction Score Baseline labs Randomization First Dose Day 84 BID Dosing for 14 Days Day 7 Day 21 Day 14 ASD NeuroCog Pain ASD NeuroCog Pain NeuroCog PTSD NeuroCog Pain

VASCULAR EHLERS-DANLOS SYNDROME EPIDEMIOLOGY Prevalence: Up to 7,500 COL3A1+ vEDS patients in US5 Median US Survival: 51 years of age1 Risk: Arterial rupture or dissection events occur in ~25% of patients before the age of 20, but increase to ~90% of patients by age 401 1 Pepin, et al. Survival is affected by mutation type and molecular mechanism in vascular Ehlers–Danlos syndrome (EDS type IV). Genet Med. 2014 Dec;16(12):881-8. 2 https://www.ehlers-danlos.com/celiprolol-and-veds/ 3 Ong K, et al. Lancet 2010; 376: 1476-84. 4 Frank M, et al. Vascular Ehlers-Danlos Syndrome: Long-Term Observational Study. J Am Coll Cardiol. 2019 Apr, 73 (15) 1948–1957 5 Truven MarketScan database and U.S> population data $ Subject to additional capital

BBEST Trial: COL3A1+ Subpopulation 76% reduction in the risk of fatal or nonfatal cardiac or arterial events in COL3A1+ EDSIVO™ patients vs. control group over mean follow-up of 47 months 75% reduction in risk of primary (cardiac or arterial events) and secondary (intestinal or uterine rupture) events in COL3A1+ EDSIVO™ patients vs. control group Efficacy: Source: Ong K, et al. Lancet 2010; 376: 1476-84. A Proportion of survival free events (%) p=0.0406 Celiprolol Control 0 25 50 75 100 Number at risk/events 13 20 13/1 19/2 12/2 15/6 9/2 11/9 8/2 4/11 2/2 3/11 B p=0.0167 12 24 36 48 60 72 Time (months) 16/5 11/3 9/12 9/3 6/14 8/3 3/14 2/3 2/14 Figure 3: Kaplam-Meier curves of event-free survival in 33 patients with positive COL3A1 mutation Primary endpoint (A). Primary and secondary endpoints (B).

pivotal phase 3 trial $ Additional capital required to conduct and complete the planned pivotal Phase 3 trial of EDSIVO™ beyond Q4 2022 Decentralized Study of Celiprolol on vEDS-related Event Reduction (DiSCOVER) Trial A Phase 3, U.S.-based, randomized, double-blind, decentralized (virtual) clinical trial to compare the efficacy of celiprolol to placebo in the treatment of patients with COL3A1-positive vEDS Primary objective: compare time to first occurrence of a confirmed clinical event between celiprolol group and placebo group among confirmed COL3A1-positive vEDS patients Secondary objectives: Safety and tolerability of celiprolol Incidence rate of composite endpoint among vEDS patients treated w/ celiprolol vs. placebo EDSIVO™ Program Status Granted Breakthrough Therapy designation (BTD) by FDA Reached agreement with FDA on critical elements of protocol design under a Special Protocol Assessment (SPA) Launched discoverceliprolol.com as an educational tool for interested parties Initiated pivotal DiSCOVER trial (study NCT05432466) Q4 2023: Full enrollment anticipated by EOY 2023 based on current enrollment rates$ Interim analysis planned at approximately 24 months after full enrollment$

Financial overview Capitalization as of January 3, 2023 CASH POSITION as of September 30, 2022 $6.4M $1.5M private placement w/Acer CEO and Chairman together with $3.3M of Q4 2022 ATM and equity line sales extended cash runway into early Q1 2023 Historical Gross proceeds Through January 3, 2023 19.7M Shares of common stock outstanding 25.3M Shares fully diluted (incl. stock options, convertible note*, and warrants) $109.7M equity financings $35.0M from Relief Collaboration $12.5M from debt financings* $157.2M * https://www.sec.gov/ix?doc=/Archives/edgar/data/0001069308/000119312522066842/d279077d8k.htm

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Document and Entity Information	Dec. 30, 2022
Cover [Abstract]
Document Type	8-K
Amendment Flag	false
Entity Central Index Key	0001069308
Document Period End Date	Dec. 30, 2022
Entity Registrant Name	ACER THERAPEUTICS INC.
Entity Incorporation, State or Country Code	DE
Entity File Number	001-33004
Entity Tax Identification Number	32-0426967
Entity Address, Address Line One	One Gateway Center
Entity Address, Address Line Two	Suite 356
Entity Address, Address Line Three	300 Washington Street
Entity Address, City or Town	Newton
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02458
City Area Code	844
Local Phone Number	902-6100
Written Communications	false
Soliciting Material	false
Pre-commencement Tender Offer	false
Pre-commencement Issuer Tender Offer	false
Title of 12(b) Security	Common Stock, $0.0001 par value per share
Trading Symbol	ACER
Security Exchange Name	NASDAQ
Entity Emerging Growth Company	false