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 11, 2017

ACER THERAPEUTICS INC.
(Exact name of registrant as specified in its charter)

 
					
Texas	 	001-33004	 	76-0333165	
(State or other jurisdiction
of incorporation)	 	(Commission
File Number)	 	(IRS Employer
Identification No.)	
		
One Gateway Center, Ste 351 (300 Washington St.)
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))	
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 8.01.	Other Events.	
On December 11, 2017, Acer Therapeutics Inc. (the “ Company ”) issued a press release entitled “Acer Therapeutics Announces Proposed Underwritten Public Offering of Common Stock,” a copy of which is attached as Exhibit 99.1 hereto and is incorporated herein by reference.
A copy of the investor presentation being used by the Company in connection with the offering is attached as Exhibit 99.2 hereto and is incorporated herein by reference.
The offering is being made pursuant to the Company’s effective shelf registration statement on Form S-3 (Registration No. 333-208314) previously filed with the Securities and Exchange Commission. The offering is being made only by means of a prospectus supplement and an accompanying prospectus.
 
Item 9.01.	Financial Statements and Exhibits.	
(d) Exhibits.

Exhibit
No.	  	Description	
		
99.1	  	Press release issued by Acer Therapeutics Inc. dated December 11, 2017 titled “Acer Therapeutics Announces Proposed Underwritten Public Offering of Common Stock.”	
		
99.2	  	Investor Presentation (December 2017).	

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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: December 11, 2017	 		 	ACER THERAPEUTICS INC.	
				
	 		 	By:	 	/s/ Harry Palmin	
	 		 		 	Harry Palmin	
	 		 		 	Chief Financial Officer	
 
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Exhibit 99.1

Acer Therapeutics Announces Proposed Underwritten Public Offering of Common Stock
NEWTON , MA – Dec. 11, 2017 – Acer Therapeutics Inc. (Nasdaq: ACER), a pharmaceutical company focused on the acquisition, development and commercialization of therapies for serious rare and ultra-rare diseases with critical unmet medical need, today announced that it intends to offer and sell shares of its common stock, subject to market and other conditions, in an underwritten public offering. All shares being offered are to be sold by Acer. Acer intends to grant the underwriters a 30-day option to purchase an additional 15% of the shares of common stock offered in the public offering.
Acer intends to use the net proceeds from this offering to fund its research and development efforts, to seek regulatory approval for EDSIVO™, to invest in pre-commercial activities for EDSIVO™ and for general corporate purposes, including working capital and other general and administrative purposes.
William Blair & Company, L.L.C. is acting as sole book-running manager of the offering.
The shares of common stock described above are being offered by Acer pursuant to its shelf registration statement on Form S-3 previously filed and declared effective by the Securities and Exchange Commission. The offering is being made only by means of a prospectus supplement and an accompanying prospectus. Copies of the preliminary prospectus supplement and the accompanying prospectus may be obtained from William Blair & Company, L.L.C., Attention: Prospectus Department, 150 North Riverside Plaza, Chicago, IL 60606; Telephone: (800) 621-0687 or by email at prospectus@williamblair.com.
This press release shall not constitute an offer to sell or the solicitation of an offer to buy these securities, nor shall there be any sale of these securities in any state or 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 jurisdiction.

About Acer Therapeutics
Acer, headquartered in Newton, MA, is a pharmaceutical company focused on the acquisition, development and commercialization of therapies for patients with serious rare and ultra-rare diseases with critical unmet medical need. Acer’s late-stage clinical pipeline includes two candidates for severe genetic disorders for which there are few or no FDA-approved treatments: EDSIVO™ (celiprolol) for vEDS, and ACER-001 (a fully taste-masked, immediate release formulation of sodium phenylbutyrate) for urea cycle disorders (UCD) and Maple Syrup Urine Disease (MSUD). There are no FDA-approved drugs for vEDS and MSUD and limited options for UCD, which collectively impact more than 4,000 patients in the United States. Acer’s product candidates have clinical proof-of-concept and mechanistic differentiation, and Acer intends to seek approval for them in the U.S. by using the regulatory pathway established under section 505(b)(2) of the Federal Food, Drug, and Cosmetic Act, or FFDCA, that allows an applicant to rely for approval at least in part on third-party data, which is expected to expedite the preparation, submission, and potential approval of a marketing application.
For more information, visit www.acertx.com .
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 regarding strategy, future operations, future financial position, future revenue, projected expenses, prospects, plans and objectives of management are forward-looking statements. Examples of such statements include, but are not limited to, statements relating to the underwritten public offering, the expected use of the net proceeds from the offering, and the development and future potential of Acer’s product candidates. Acer 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 market conditions, the satisfaction of customary closing conditions related to the public offering, and the process of developing, obtaining regulatory approval for and commercializing drug candidates that are safe and effective for use as human therapeutics. Acer 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. You should review additional disclosures we make in our filings with the Securities and Exchange Commission, including our Quarterly Reports on Form 10-Q and Annual Report on Form 10-K and the Registration Statement on Form S-3 (File No. 333-208314) for the public offering. You may access these documents for no charge at http://www.sec.gov .
 
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Investor Contact:
Hans Vitzthum
LifeSci Advisors
Ph: 617-535-7743
hans@lifesciadvisors.com
# # #
 
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Developing Therapeutics for the Treatment of Serious Rare Diseases with Significant Unmet Medical Needs December 2017 NASDAQ: ACER Exhibit 99.2

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, future financial position, future revenues, projected expenses, prospects, plans and objectives of management are forward-looking statements. Examples of such statements include, but are not limited to, statements relating to expectations regarding the capitalization and resources of the company; the potential for EDSIVO™ (celiprolol) and ACER-001 to safely and effectively target diseases; the commercial or market opportunity in any target indication; the adequacy of the company’s capital to support its future operations and its ability to successfully initiate and complete clinical trials and regulatory submissions; the ability to protect the company’s intellectual property rights; the nature, strategy and focus of the company; future economic conditions or performance; and the development, expected timeline and commercial potential of any product candidates of the company. Acer 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 availability of sufficient resources of the company to meet its 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 Acer’s intellectual property, risks related to the drug development and the regulatory approval process and the impact of competitive products and technological changes. Acer 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. You should review additional disclosures we make in our filings with the Securities and Exchange Commission, including our Quarterly Reports on Form 10-Q and our Annual Report on Form 10-K. You may access these documents for no charge at http://www.sec.gov.

Offering Summary Issuer Acer Therapeutics (NasdaqCM: ACER) Offering Size(1) Approximately $10.0M-$15.0M (100% Primary) Underwriters’ Option 15% (100% Primary) Use of Proceeds Acer intends to use the net proceeds from this offering to fund its research and development efforts, to seek regulatory approval for EDSIVO™, to invest in pre-commercial activities for EDSIVO™ and for general corporate purposes, including working capital and other general and administrative purposes. Acer may use a portion of the net proceeds from this sale to acquire or invest in complementary businesses, technologies, product candidates or other intellectual property, although Acer has no present commitments or agreements to do so. Sole Bookrunner William Blair & Company, L.L.C. Lock Up Period 90 days, subject to customary exceptions Current Investors TVM Capital has indicated interest in purchasing up to $4.0 million of common shares in this offering 1) Limitation subject to SEC’s baby shelf rule.

Acer is a pharmaceutical company that acquires, develops and commercializes therapies for serious rare and ultra-rare diseases with significant unmet medical needs. Headquartered: Newton, MA Headcount: 8 Founded: December 2013 Public: September 2017 Cash and cash equivalents: $8.4M (as of September 30, 2017) Pre-deal, cash is expected to be sufficient through expected NDA filing for EDSIVO™ in 1H 2018 Acer Corporate Overview

Chris Schelling, CEO and Founder 18 years of biotech/pharma strategic and orphan drug expertise Will Andrews, M.D., Chief Medical Officer 17 years in both Clinical Development and Medical Affairs in multiple therapeutic areas, with a focus on and extensive experience in rare diseases. Significant medical marketplace and product launch experience, having served as the medical lead for six product launches. He received his undergraduate degree in biology from Harvard University and his M.D. degree from Yale University School of Medicine Harry Palmin, Chief Financial Officer 20+ years of corporate experience Pamela Williamson, Acting Head, Regulatory Affairs 30 years of orphan drug regulatory and CMC expertise Jefferson Davis, Acting Chief Business Officer 20+ years of drug discovery, business and corporate development expertise Philip Sager, M.D., Strategic Clinical Consultant – EDSIVO™ A senior healthcare executive (>25 years of working experience) with strategic and operating experience; extensive U.S. and international regulatory leadership, including Chair of the FDA Cardio-Renal Advisory Committee and the PhARMA Topic Leader to the ICH E14 Regulatory Guidance Management Team Management has extensive expertise in orphan development & commercialization

Investment Highlights Lead candidate (EDSIVO™) is a new chemical entity (NCE) for treatment of Vascular Ehlers-Danlos syndrome (vEDS) with a robust data package, including survival endpoints and long-term registry data at time of potential launch ACER-001 for treatment of Urea Cycle Disorders (UCD) and Maple Syrup Urine Disease (MSUD) is a proprietary, taste-masked, immediate release formulation of FDA/EMA approved products that are projected to generate $200M in revenue this year (U.S.)1 Both assets have been granted U.S. orphan status, are unencumbered and target indications with significant unmet medical needs Multiple key regulatory catalysts expected over next approximately 24 months NDA filing for EDSIVO™ expected in 1H 2018 NDA filing for ACER-001 anticipated in 1H 20192 Post-deal, expected to have sufficient capital through EDSIVO™ launch and commercialization 1 http://ir.horizon-pharma.com/static-files/9cdc7987-2bb1-4292-ae29-34f16b01eab8 2 Subject to Acer’s ability to obtain sufficient capital resources.

Program / Indication Novel MOA / Unique Characteristics Phase 1 Phase 2 Phase 3 NDA Market EDSIVOTM (celiprolol) vEDS (COL3A1+) Improves hemodynamic stability; decreases vascular resistance ACER-001 (reformulated sodium phenylbutyrate) UCD Comparable to Buphenyl; taste-masked MSUD Inhibition of BCKD kinase to increase BCAA metabolism Clinical Pipeline Key Regulatory Milestones NDA filing for EDSIVO™ expected in 1H 2018 NDA filing for ACER-001 anticipated in 1H 2019* * Subject to Acer’s ability to obtain sufficient capital resources.

Autosomal dominant connective tissue disorder of collagen synthesis caused by mutations in the COL3A1 gene for type III procollagen Characterized by arterial aneurysms, dissections and/or ruptures Median survival is 51 years of age Identified in over 2,000 patients in the U.S. Vascular Ehlers-Danlos syndrome (vEDS) Celiprolol is a New Chemical Entity (NCE) in the U.S. EDSIVO™ (celiprolol) showed statistically-significant improvement in event-free survival (EFS) compared to control in vEDS patients Clinical benefits seen in vEDS are via novel, disease-modifying MOA Currently pre-NDA for treatment of vEDS EDSIVOTM Product Profile Significant unmet medical need with no direct competition Expected NDA filing in 1H 2018 Orphan pricing with robust program to support reimbursement & access Launch in 50-100 vEDS Centers of Excellence (COE) The Opportunity EDSIVO™ Overview

Ehlers-Danlos syndrome (EDS) is a group of hereditary disorders of connective tissue vEDS (EDS type IV) is the severe subtype: Characterized by aneurysms, dissections and/or ruptures Vascular Gastrointestinal Uterine Autosomal dominant (50%); spontaneous mutations (50%) Diagnosed by clinical symptoms and confirmed by presence of mutations in the COL3A1 gene Events occur in 25% of patients before the age of 20, but 90% by the age of 40 Median age of death is estimated to be 51 years No effective therapeutic options for vEDS Current treatment is focused on surgical intervention Vascular Ehlers-Danlos syndrome (vEDS) Fig. 3 Distribution of 132 vascular complications in 24 patients with a clinical diagnosis of EDS type IV. J Vasc Surg 2005;42:98-106.

“In vascular EDS the body lacks sufficient type III collagen, a molecule that contributes to the strength of the skin, intestines, uterus, and most importantly, the blood vessels.” “People with vascular EDS live with the knowledge that they will die from this condition.” “They are also told that there are no effective treatments. There are no medications that are known to strengthen the tissues or delay blood vessel rupture.” “Attempts at surgical repair are often delayed; there is confidence that the patient will die within hours if nothing is tried. This is because the tissues are so weak that they often simply fall apart during surgery – akin to trying to sew together wet tissue paper.” “Of all the conditions that I care for, I hate this one the most. It not only drastically shortens the length of life, but also robs people of any meaningful sense of hope and quality of life – always anticipating that the shoe will drop at any moment.” vEDS KOL Geneticist January 2010 Vascular Ehlers-Danlos syndrome (vEDS)

Cardiology in Review 2017;25: 247–253 EDSIVO™ Unique Mechanism of Action EDSIVO™ has a unique pharmacological profile: Selective β1 and ⍺2 adrenergic receptor antagonist β2 and β3 adrenergic receptor agonist Intrinsic sympathomimetic activity (ISA+) Lacks non-specific membrane effects Void of blood pressure lowering in normotensive people Most vEDS patients are normotensive, thus the protective effect of celiprolol is unlikely to be through blood pressure lowering (β1 antagonism) EDSIVO™ positive effects in vEDS patients are thought to be through: Providing more stable hemodynamic conditions that lead to a less fragile arterial wall Upregulation of collagen synthesis via TGF-β, thus strengthening the arterial wall and reducing its susceptibility to rupture EDSIVO™ is the only agent to show clinical benefit in patients with vEDS

Multicenter, prospective, randomized, open trial with blinded endpoint assessment Design: 9 sites: eight in France, one in Belgium Location: Inclusion criteria adapted Villefranche diagnostic criteria: 1 major criterion and 2 minor criteria, or 4 minor criteria needed for enrollment Eligibility: 53 patients with clinical Vascular Ehlers-Danlos syndrome Randomly assigned to 5 years treatment with 1) celiprolol or 2) no treatment Enrollment: Ages 15 to 65 (mean 35), female/male ratio 2:1 Important phenotype characteristics equally balanced between celiprolol and control Demographics: Celiprolol administered twice daily Up-titrated every 6 mos. by 100 mg/day to max. 400 mg/day Dosing: Primary: arterial events (rupture/dissection, +/-fatal) Secondary: intestinal or uterine rupture Endpoints: Mean duration of follow-up 47 months; trial stopped early for treatment benefit Duration: French Ministry of Health; PI: Prof. Pierre Boutouyrie Funding / PI: ClinicalTrials.gov, number NCT00190411 Ong Lancet 2010; 376: 1476-84. EDSIVO™ Pivotal Clinical Trial

Results & Analysis: Trial stopped early for treatment benefit (mean follow-up 47 months) The primary endpoint (arterial dissection or rupture) affected 5 (20%) celiprolol patients and 14 (50%) controls (hazard ratio [HR] 0.36; p=0.04) Primary and secondary endpoints (intestinal or uterine rupture) affected 6 (24%) celiprolol patients and 17 (61%) controls (HR 0.31; p=0.01) Post-hoc analysis of 33 patients with confirmed COL3A1 mutation indicated equal benefit for the primary (HR 0.24; p=0.04) and secondary endpoints (HR 0.25; p=0.02) Author’s Comments: “We suggest that celiprolol might be the treatment of choice for physicians aiming to prevent major complications in patients with vEDS” Primary Endpoint Primary + Secondary Endpoints EDSIVO™ Statistically Significant Efficacy Ong Lancet 2010; 376: 1476-84.

EDSIVO™ vEDS Patient Registry Paris (AP-HP) Registry PIs: Michael Frank, Xavier Jeunemaitre 144 patients enrolled in registry 100% of patients in registry have COL3A1 gene mutation >80% of patients on celiprolol Study Period: Jan. 2000 to Dec. ‘14 (for initial referral patients), followed until 2017 (for follow-up visits) Median Age at Diagnosis: 35 Median Duration F/U: 5.55 years [3.25 - 8.55 years]; max F/U: 20 years Targeting e-published manuscript in 1Q 2018 Acer will reference data in NDA 14

EDSIVO™ Data Package Pivotal Clinical Trial n = 53 patients (62% COL3A1+) Statistically-significant improvement in 1º endpoint EFS (p=0.04) Paris Registry: n = 144 patients (100% COL3A1+) >80% patients on celiprolol Sanofi MHRA Dossier >13,000 pages (220 studies) Pharmacology, PK/PD, repro/tox, clinical safety Updated CMC Package Current analytical methods U.S. manufacturing standards EDSIVO™ Regulatory Plan Targeting NDA submission in 1H 2018

vEDS Market Sizing* vEDS patient population for basis of market sizing = 4,169 patients 2 instances of the EDS Dx Code 756.83 separated by ≥ 2 months Includes at least one other Dx or CPT code relevant to vEDS -AND- Excludes hypermobility syndrome * Based on sampling of phenotype, rather than genotype

Accelerate Diagnosis https://www.genetests.org/genes/?gene=COL3A1 * Based on sampling of phenotype, rather than genotype Facial Recognition Program Patients with vEDS have relatively similar / identifiable facial features Want a quick, cost-effective test to potentially help screen for vEDS patients in the clinic Acer is looking to collaborate with a leading AI firm to establish a phenotype – genotype database Facial recognition software is in the majority of genetic clinics in the U.S. May lead to earlier and more accurate diagnosis Broad Familial Genetic Testing Program According to HVH Patient Precision Analytics, there are ~4,000 to 5,000 patients with vEDS in the U.S.* According to genetic labs, ~2,000 patients have had a genetic test that confirms COL3A1 status A broad genetic testing program for COL3A1 (autosomal dominant) could substantially increase the number of confirmed patients Current test costs: $1,000 - $5,000 / test and are not always reimbursed Opportunity to centralize, reduce cost: $500 / test (target)

18 vEDS Patient and Payer Demographics

EDSIVO™ Proposed Commercial Strategy EDSIVO™ Proposed Launch Plan* Identify vascular medicine specialists / cardiologists who: Can manage patients and their families Are familiar with orphan therapies Refer to CV surgeons Work closely with a team of specialists Will focus initially on cardiology/vascular medicine as “vEDS HOME” Academic centers vEDS COEs 50 COEs at launch Grow to 100 COEs in 3 years ~20-50 vEDS patients/COE Focused and dedicated medical & commercial effort to support launch (n~20) 19 * Commercialization of EDSIVO is subject to (a) Acer’s ability to obtain sufficient capital resources and (b) FDA approval. Neurology OB/GYN Radiology Emergency Medicine Surgery Genetics Vascular Medicine Connective Tissue Genetic Labs COEs

20 EDSIVO™ HEOR Precision Health Economics is developing a health economic (cost-consequence) model demonstrating the economic and clinical value of vEDS Centers of Excellence, and the potential impact of EDSIVO™ on patient outcomes These models will help quantify and communicate cost offsets associated with the COE model for hospital systems and payers (if needed) It will also help support orphan pricing for EDSIVO™ with key stakeholders

If approved, EDSIVO™ will be the only FDA-approved therapy to treat vEDS patients 2,000 to 5,000 vEDS patients in the U.S. Orphan pricing well supported by initial payer research, with additional validation from HEOR models Provide a robust patient assistance program (PAP) to help offset costs (so there will be little/no incentive for vEDS patients in the U.S. to attempt to obtain celiprolol elsewhere) Granted U.S. Orphan Drug Designation for vEDS (January 2015) 5 years NCE exclusivity 7 years orphan exclusivity Potential for +0.5 years pediatric exclusivity 50-100 Centers of Excellence proposed Focused, dedicated medical & commercial group (n~20) EDSIVO™ Market Opportunity

A group of metabolic genetic diseases that lead to toxic build-up of NH4+ Currently treated with Ravicti, Buphenyl, Ammonul, and a highly-restricted diet >2,000 patients with UCD in the U.S.; ~600 patients treated with sodium / glycerol phenylbutyrate Urea Cycle Disorders (UCD) A metabolic genetic disease that leads to toxic build-up of leucine and other branched-chain amino acids Currently managed with a highly-restricted diet; poor compliance Well-defined patient population with ~800 eligible patients in the U.S. Maple Syrup Urine Disease (MSUD) Expected NDA filing in 1H 2019* Issued U.S. / EU patents covering methods of use in MSUD Orphan drug designation in MSUD Advantageous orphan pricing with robust program to support reimbursement and patient access The Opportunity ACER-001 Overview A taste-masked, immediate release formulation of sodium phenylbutyrate First office action (USPTO) on formulation patent PK/BE study to show equivalence to sodium phenylbutyrate ACER-001 Product Profile * Subject to Acer’s ability to obtain sufficient capital resources.

Urea cycle disorders are a group of genetic disorders caused by mutations that result in a deficiency of one of the six enzymes in the urea cycle. These enzymes are responsible for removing ammonia from the blood stream The estimated incidence of urea cycle disorders is 1 in 8,500 births Treatment options for UCD include: Phenylbutyrate (Buphenyl, Ravicti) IV Benzoate / Phenylacetate (Ammonul) Sodium Benzoate Restricted Diet Liver Transplantation The Urea Cycle Mechanism of ammonia diversion from the urea cycle with the administration of sodium phenylacetate, sodium benzoate, or sodium phenylbutyrate (a prodrug of phenylacetate) Urea Cycle Disorders (UCD)

In addition to lowering levels of ammonia in patients with urea cycle disorders (UCD), sodium phenylbutyrate (NaPB) also significantly reduces branched-chain amino acids (BCAAs)1 NaPB’s ability to lower leucine and other BCAAs could provide clinically-meaningful benefit in another genetic disease: Maple Syrup Urine Disease (MSUD)2 Open label pilot study at BCM – 3 healthy and 5 MSUD subjects with late onset disease Despite the short treatment duration (3 days) NaPB showed statistically significant (intra-subject) reduction in leucine in 75% of the subjects 1Burrage et al., Mol. Genet. Metab. 2014 2Brunetti-Pierri et al., Hum Mol Genet. 2011 February 15; 20(4): 631–640 Retrospective study of BCAA levels in 553 UCD patients treated with NaPB or without NaPB: Lower BCAAs in UCD

MSUD is an inborn error of Branched-chain Amino Acid (BCAA) – leucine, isoleucine, valine – metabolism Caused by deficiency of the mitochondrial Branched-chain Keto Acid Dehydrogenase complex (BCKDC) ~800 patients in U.S., ~3,000 patients worldwide MSUD Family Support Group has >500 patients Part of newborn screening in U.S., UK, Germany High leucine levels lead to chronic and acute neurological damage Lower IQ Mental impairment (poor cognitive function) Social impairment (poor executive function) Metabolic decompensation (seizures and coma) A highly-restricted diet is the primary treatment Consists of BCAA-free synthetic foods and formula Very few foods have low BCAAs (fruits & vegetables) Balancing act: enough BCAAs for growth & development Maple Syrup Urine Disease (MSUD) indicates p < 0.05, *** p < 0.001 compared to the control group* * Muelly 2011 Neuropsychiatric and Neurochemical Sequelae of MSUD

ACER-001 Taste-Masked, Immediate Release Mouth → Stomach Excellent protection for several minutes at mouth pH followed by rapid release at stomach pH Phenylbutyrate Formulations ACER-001 RAVICTI BUPHENYL Efficacy/Safety in UCD ✓ ✓ ✓ Efficacy/Safety in MSUD ✓ ✘ ✓ Palatability / Compliance ✓ ✓ ✘ Relatively Reasonable Orphan Pricing ✓ ✘ ✓ Acer is working closely with KOLs & patient advocacy groups to provide a compelling alternative treatment option for patients with UCD ACER-001 provides significant differentiation from other approved formulations of phenylbutyrate Ravicti / Buphenyl reported 2016 revenue = $170M (U.S. UCD only) Ravicti annual price: >$500K pppy* Buphenyl annual price: ~$120K pppy * Ravicti pppy is based on patient weight

Cannibalize existing sodium phenylbutyrate market share in UCD Taste-masked, immediate-release formulation Competitively priced Life cycle expansion opportunity in MSUD Barriers to entry: Filed formulation patent application (January 2016) Issued patent (US/EP) “Methods of modulation of branched chain acids and uses thereof” 505(b)(2) Exclusivity: 3 years in U.S. for UCD Obtained U.S. Orphan Drug Designation for MSUD (August 2014) Pediatric Exclusivity: 6 months Provide a robust PAP to help offset costs ACER-001 Market Opportunity

Acer Financial Overview Cash and cash equivalents: $8.4M (as of September 30, 2017) Pre-deal, expected to have sufficient funding through NDA filing for EDSIVO™ Capitalization at November 2017 6.5M shares of common stock 6.9M shares of common stock fully diluted* $28M invested to date through November 2017 TVM Capital has been the lead investor *Excluding 300,000 of Opexa legacy warrants with exercise price >$100 and expiry within one year

Acer Summary Lead candidate (EDSIVO™) is a new chemical entity (NCE) for treatment of Vascular Ehlers-Danlos syndrome (vEDS) with a robust data package, including survival endpoints and long-term registry data at time of potential launch ACER-001 for treatment of Urea Cycle Disorders (UCD) and Maple Syrup Urine Disease (MSUD) is a proprietary, taste-masked, immediate release formulation of FDA/EMA approved products that are projected to generate $200M in revenue this year (U.S.)1 Both assets have been granted U.S. orphan status, are unencumbered and target indications with significant unmet medical needs Multiple key regulatory catalysts expected over next approximately 24 months NDA filing for EDSIVO™ expected in 1H 2018 NDA filing for ACER-001 anticipated in 1H 20192 Post-deal, expected to have sufficient capital through EDSIVO™ launch and commercialization 1 http://ir.horizon-pharma.com/static-files/9cdc7987-2bb1-4292-ae29-34f16b01eab8 2 Subject to Acer’s ability to obtain sufficient funding