Issuer Free Writing Prospectus

Filed Pursuant to Rule 433

Registration No. 333-201731

January 28, 2015

Opexa Therapeutics, Inc.

NASDAQ: OPXA

January 2015

The Woodlands, TX

Precision Immunotherapy

®

2

Free Writing Prospectus Statement

•

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•

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3

Forward-Looking Statements

All

statements

in

this

presentation

other

than

those

of

historical

fact,

including

statements

regarding

our

preclinical

and

clinical

development

plans

for

Tcelna®

and

OPX-212,

our

research

and

other

development

programs,

our

ability

to

undertake

certain

activities

and

accomplish

certain

goals,

projected

timelines

for

our

research

and

development

activities

and

possible

regulatory

approvals,

if

any,

our

expectations

regarding

the

relative

benefits

of

our

product

candidates

versus

competitive

therapies,

our

expectations

regarding

the

possibility

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licensing

or

collaborating

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parties

regarding

our

product

candidates

or

research,

and

our

expectations

regarding

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therapeutic

and

commercial

potential

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product

candidates,

research,

technologies

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Actual

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without

limitation,

risks

associated

with

the

process

of

discovering,

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that

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and

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as

human

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and

risks

inherent

in

the

effort

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business

around

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drugs.

Although

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believe

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level

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In

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Securities

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4

Opexa Investment Highlights

PIPELINE

•

Tcelna

®

: Phase 2b for secondary progressive multiple sclerosis (SPMS), limited

competition, $7BN overall market potential, encouraging prior trials (Phase IIb RRMS,

Phase I/II SPMS)

•

OPX-212: Pre-IND for neuromyelitis optica (NMO), no approved therapies, orphan

indication

TECHNOLOGY

VALIDATION

•

Precision immunotherapy for T-cell-mediated autoimmune diseases

•

Proprietary Platform: potential to yield multiple candidates personalized to each patient

•

Company owned and scalable cGMP manufacturing facility

•

Strong patent estate (98 domestic and international)

•

Option

agreement

secured

with

Merck

Serono

for

Tcelna

–

strong

potential

partner

•

FDA Fast Track designation for Tcelna in SPMS

•

Esteemed Scientific Advisory Board

5

Offering Summary

Issuer

Exchange/Ticker

Structure

Offering size

Subscription Price

Warrant structure

Oversubscription privilege

Use of proceeds

Co-managers

Opexa Therapeutics, Inc.

NASDAQ / OPXA

Rights Offering

Up to 28,776,419 Units

Each Unit composed of one share of common stock and one warrant

TBD

Range expected $0.65-$0.75

Exercise price: $0.50 per share from issuance through June 30, 2016; $1.50 per share from

July 1, 2016 through 3-year expiration

Redeemable for $0.01 per share upon certain conditions

Exercisable for cash unless no effective registration statement

Allocated pro rata up to available Units not purchased by other

holders, subject to limitations

Funding of ongoing Phase IIb Abili-T study in SPMS patients

Funding of preclinical and/or clinical development for OPX-212 in NMO

For general corporate purposes and operational purposes

Maxim Group

National Securities Corp.

6

Opexa Investment Thesis

Why a Rights Offering?

•

A successful rights offering would give Opexa sufficient capital

to fund operations through 2016.

–

Complete

the

ongoing

Phase

2b

clinical

trial

in

SPMS

and

release

data

–

Potentially initiate a Phase 1/2 trial with OPX-212 in neuromyelitis optica (NMO)

Background

•

Opexa has previously raised over $90 million, with most being invested in its T-cell immunotherapy platform.

•

Opexa has conducted two Phase 1 trials and is currently conducting its second Phase 2 trial having treated both RRMS

and SPMS patients with Tcelna. Over 400 individuals in total have been enrolled in Opexa’s clinical trials for Tcelna,

including the ongoing Phase 2b SPMS trial.

•

Current Phase 2b trial is designed to show whether Tcelna could improve clinical outcomes -

data expected in 2H 2016.

–

Enrollment of 190 patients in a randomized, placebo-controlled trial completed

–

The Company may apply for accelerated approval and breakthrough designation with the FDA following the completion of the

current

Phase

2b

trial

in

the

event

of

positive

results

(primary

endpoint-whole

brain

atrophy;

secondary-progression)

•

Fast Track Designation obtained from the U.S. FDA for Tcelna in SPMS.

•

In addition, the Company has further leveraged its platform to move into neuromyelitis optica (NMO), an orphan (rare)

disease with no FDA-approved treatments. This program is in the pre-IND stage.

•

Immunotherapy approaches have been validated and are increasingly being applied in oncology.

•

Opexa has been refining its approach for over a decade focusing on autoimmune diseases, specifically, Tcelna for MS.

•

Based, in part, on

data generated in prior MS trials, Merck Serono, a leading pharma company in MS, entered into an

option and license agreement with Opexa to potentially license Tcelna for MS, worldwide, excluding Japan. Should

Merck Serono exercise its option, they would fund any future Phase III studies and commercial activities with potential

milestone payments and royalties coming to Opexa upon success of

the program.

HOW DOES TCELNA WORK?

7

8

The Root Cause of Multiple Sclerosis

Adapted by permission from Macmillan Publishers Ltd:  NATURE REVIEWS

IMMUNOLOGY 3, 483-492 (June 2003), copyright (2003)

Cytokines

Damage

Damage

•

MS is an inflammatory disease in which the

insulating cover of the nerve fibers (the

myelin sheath) in the brain are damaged by

the body’s own immune system. There is no

cure for MS.

•

In MS patients, the faulty immune system is

unable to prevent the attack of myelin

reactive T-cells (MRTC)

•

MRTC cross the blood brain barrier, enter

the brain leading to a two pronged attack

through:

1.

Destruction of myelin sheath, the protective

coating of nerve fibers

2.

Destruction of oligodendroglial cells, which

are responsible for producing myelin

Myelin peptide

Activated T-

cells degrade Myelin and

Damage Myelin Producing  Cells

9

Tcelna Could Address the Root Cause of Multiple Sclerosis by

Preventing Demyelination and Enabling Remyelination

Adapted by permission from Macmillan Publishers Ltd:  NATURE REVIEWS

IMMUNOLOGY 3, 483-492 (June 2003), copyright (2003)

Opexa’s Strategy

Tcelna programs the immune system to

specifically

recognize only the damaging T-

cells (MRTC), thereby inhibiting further

destruction of the myelin sheath and

potentially enabling remyelination

•

Immune cells, including Tregs, have been

primed, or sensitized to specifically target

the pathogenic MRTC for elimination or

regulation

•

Elimination of harmful MRTC may lead to:

o

Stabilization of disease by preventing

further destruction of myelin

o

Improvement in condition by allowing

Oligondendroglial cells to remyelinate

axons (neuroprotection)

RESULTS AND EXPLANATION OF RRMS &

RESULTS AND EXPLANATION OF RRMS &

SPMS CLINICAL TRIALS

SPMS CLINICAL TRIALS

10

11

Business Strategy and Rationale for Pursuing

Secondary Progressive MS (SPMS)

•

Opexa

completed

a

Phase

2b

clinical

study

in

RRMS

patients

–

Although the primary MRI endpoint was not met, the clinical signal was encouraging

–

In a subset of more active RRMS subjects, patients treated with Tcelna saw a statistically

significant improvement in disability, and the therapy was safe and well tolerated

–

Opexa completed formal End of Phase 2 meetings with the FDA and obtained support to move

into Phase 3 studies in RRMS

•

In

separate

Phase

I/II

trials

in

SPMS

patients,

35

subjects

treated

with

Tcelna showed encouraging results

–

80% of patients showed no disease progression following two years of treatment

–

Substantial reduction in relapse rate following two years of treatment

•

One relapse observed in 21 years of cumulative patient follow up

–

No worsening in physical or psychological condition following two years of treatment

–

Well tolerated, no Serious Adverse Events

•

Strong interest from Key Opinion Leaders, clinical investigators, patients

and potential partners to advance in SPMS

•

Substantial unmet medical need in SPMS

–

Only one product currently approved for SPMS indication with limited use due to cardio toxicity

•

Novel, personalized T-cell approach differentiates Opexa from competition

12

Phase 2b RRMS prior clinical trial

Tcelna showed 37% improvement over placebo (mITT)

(secondary endpoint measurement, primary MRI endpoint measure not met)

n=94

n=48

37%

Total mITT population

n=142

0.214

0.339

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

37% Reduction in Annualized Relapse Rate (ARR)

Tcelna

Placebo

13

Phase 2b RRMS Prior Clinical Trial

Reversal of Disability in Prospective Analysis in More Active Patients

Sub-population of patients (n=50) with more progressed/active disease

profile (baseline ARR >1)

Statistically Significant

Improvement in Disability (p=0.045)

55% Reduction in ARR

Change in Disability (EDSS)

at Week 52

Annualized Relapse Rate (ARR) at week 52

2.4

2.23

2.2

2.39

2.10

2.15

2.20

2.25

2.30

2.35

2.40

2.45

Baseline                             Week 52

Tcelna

Placebo

(p=0.045)

0.28

0.63

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

Tcelna

Placebo

55%

14

Phase I/II SPMS Prior Clinical Trials

Tcelna Stabilizes Disease in SPMS at 2 Years

80%

of

patients

showed

no

further

disease

progression

by

EDSS

at

2

years

Historical Disease

Progression

Tcelna Open Label

(n=35)

*A small percentage of patients in pooled analysis showed an

improvement (i.e. decrease in progression)

**Historical control: ESIMS Study,

published Hommes Lancet 2004

80%

20%

40%

0%

20%

40%

60%

80%

100%

Stabilization vs. Historical Progression

Stable

Progressed

15

Tcelna in Secondary Progressive MS

•

Secondary Progressive MS market

potential in North America could

exceed $7 billion (for all therapies)

•

Roughly 150,000 SPMS patients in

North America

•

Only one drug approved for SPMS in

U.S. (none in EU or Asia)

-

Drug not suitable for chronic use

due to severe side effects

Tcelna being developed to be a

potential therapy of choice in SPMS

SPMS

450,000 Individuals in North America diagnosed with MS;

30-45 % potentially have an SPMS diagnosis

Market Size:

$7 Billion (est.)

Relapsing Remitting MS;

Clinically Isolated Syndrome;

Primary Progressive MS

16

Tcelna

Lead Program Targeting Secondary Progressive MS patients

Fast Track Designation by FDA

•

Phase 2b trial is fully enrolled: 190 patients with SPMS

•

Top line data expected in 2H 2016

•

Design

–

Double-blind, 1:1 randomized, placebo-controlled

–

35 clinical sites in USA and Canada

–

Two annual courses of personalized therapy

–

Efficacy Endpoints: Primary-Whole Brain Atrophy, Secondary-Disease

Progression

•

Immune Monitoring being conducted in parallel

–

Comprehensive biomarker analysis

17

Merck Serono Agreement

Agreement signed 2013; strong potential partner

Option and License Agreement for worldwide rights to all Multiple

Sclerosis indications, excluding Japan

•

If Merck Serono exercises option:

–

Merck Serono to fund any Phase 3, pre-commercial and commercial activities

–

Merck Serono obtains rights to develop Tcelna for all MS indications

–

Worldwide rights excluding Japan

•

Opexa received $5 million upfront option fee at signing

•

Opexa

has

potential

to

receive

additional

$220

million

in

option

exercise and milestone             

payments

•

Opexa has potential to receive royalties ranging from 8% to 15% of annual net sales, with

step-ups occurring if net sales exceed $500 million, $1 B & $2 B

•

Opexa maintains key rights

–

Development and commercialization rights to Tcelna in Japan

–

Certain manufacturing rights

–

Co-development funding option in exchange for increased royalties

–

Rights to all other disease indications

OPX-212:

NEUROMYELITIS OPTICA (NMO)

18

NMO: A Rare Disease with High Unmet Need and 

Significant Market Potential

•

Neuromyelitis optica (NMO) is a rare or orphan autoimmune

disease, affecting the optic nerves and the spinal cord

•

There are no FDA-approved therapies for NMO

•

Any therapy that could achieve tolerization of the AQP-4

reactive T-cells may offer a cure for NMO

•

Opexa retains world wide rights to OPX-212.  Product has

potential to generate $300-$500 million in peak sales, subject

to successful clinical development

•

IND filing expected in Mid 2015

•

Open label Phase I/II clinical trials expected to start in 2H

2015 (subject to IND acceptance and financing)

An orphan disease with no FDA-approved therapy

Image reprinted with permission from MultiView, Inc.

19

20

Recent and Upcoming Expected Milestones

2016

2017

2014

2015

1H

2017:

Top

line

results

expected from Phase I/II trial

with OPX-212 in NMO (subject

to IND acceptance and financing)

Mid-2015:

File

IND/CTA with US FDA

and/or Canadian health

authorities

2016/17:

Apply for orphan

and fast track designation for

OPX-212 in NMO

1H 2014:

Complete

enrollment in Phase

IIb SPMS study

2H 2014:

Initiate

second disease

indication: NMO

2H 2015:

Initiate Phase I/II

clinical study with OPX-212 in

NMO (subject to IND

acceptance and financing)

2H

2016:

Results

from

Immune Monitoring

(biomarker) program

expected

2H

2016:

Top

Line

results expected in

Phase IIb SPMS trial

20

21

Experienced Management Team and Board of Directors

Neil Warma, President & CEO, Director

›

19+ years international healthcare experience with large Pharma and emerging

biotechnology companies

›

Former Senior Management, Novartis Pharmaceuticals, Basel, Switzerland

›

Former CEO, Viron Therapeutics, Inc.

›

Co-founder and President of MedExact Inc., a company subsequently acquired

Karthik Radhakrishnan, Chief Financial Officer

›

10+ years of health care capital markets experience

›

Formerly, Vice President at ING Investment Management

›

MBA, MS in Engineering, CFA charter holder

Don Healey, Ph.D., Chief Scientific Officer

›

25+ years of experience in cellular immunology and immune regulation

›

Former Director of Immunology, Argos Therapeutics

Donna Rill, Chief Development Officer

›

30 years in cell and gene therapy research and clinical application

›

Designed and validated cGMP Cell & Gene Therapy Laboratories, Vector

Production facilities, and Translational Research Labs

Kenny Frazier, VP of Clinical Dev. and Regulatory

Affairs

›

25+ years of extensive clinical and regulatory experience

›

Formerly, Head of Clinical Operations, Lexicon Pharmaceuticals and Tanox,

Inc.

Board of Directors

Timothy Barabe

Board member of Arqule, Inc.; Former

CFO of Affymetrix, Human Genome

Sciences, Inc., Regent Medical UK and

Sandoz  GmbH

Dr. Hans-Peter Hartung

Chair of Neurology at Heinrich-Heine

University, Germany; Executive Board

member of ECTRIMS

Gail J. Maderis

CEO, BayBio, Former CEO of Five

Prime Therapeutics, Founder of

Genzyme Molecular Oncology

Michael S. Richman

CEO, Amplimmune

Scott B. Seaman

Executive Director,

Alkek Foundation

Neil K. Warma

President & CEO, Opexa

22

SPMS Scientific Advisory Board

Dawn McGuire, M.D., FAAN (Chair)

•

Advisory Council of the Gill Heart Institute

•

Former Vice President of Clinical Research at Elan Pharmaceuticals

Hans-Peter Hartung, M.D

•

Chair of Neurology at Heinrich-Heine University, Düsseldorf

•

Executive Board member of ECTRIMS, World Health Organization Advisory Board on MS

Mark S. Freedman, M.D.

•

Director of the Multiple Sclerosis Research Unit at Ottawa Hospital

•

Multiple Sclerosis Society of Canada, National MS Society (USA)

•

ACTRIMS committee member

Clyde Markowitz, M.D.

•

Director of MS Center at the University of Pennsylvania

Doug Arnold, M.D.

•

James McGill Professor Neurology and Neurosurgery at the Montreal Neurological Institute

Edward Fox, M.D., Ph.D.

•

Director of Multiple Sclerosis Clinic of Central Texas

•

Advisory Committee, Lone Star Chapter of the National Multiple Sclerosis Society

APPENDIX

APPENDIX

23

IMMPATH

:

PROPRIETARY DRUG DEVELOPMENT PLATFORM

24

®

25

Personalized T-cell vaccines

Consisting of Attenuated Antigen Specific T-cell Clones

•

Opexa identifies the exact T-cell

responsible for T-cell-mediated

autoimmune damage, expands the T-cells

in cGMP facility

•

Therapeutic dose of attenuated T-cell

clones is injected subcutaneously

•

Immune system recognizes the large

volume of cells (30-45 million) under the

skin as potential foreign pathogens

•

Attenuated T-cells believed to trigger an

immune response specifically targeting

circulating pathogenic reactive T-cells

Tcelna: lead product candidate in Phase 2b

trial for secondary-progressive multiple

sclerosis

Tcelna

®

Personalized T-cell Vaccine

26

Business Differentiator: Manufacturing Process

Designed for commercialization, Owned and managed by Opexa

Cryopreservation

Formulation/

Irradiation of each

dose as required

Administration: 5

subcutaneous

injections/year

Manufacturing and QC

Dispensation

35 days

Epitope Profiling

1 day

14 days

-

Red Cross

-

Blood Group Alliance

Epitope Profiling

Expansion of antigen specific T-cells

Annual

course

of

treatment

is

5

doses

manufactured

from

a

single

procurement

27

Comprehensive Process to Determine Optimal Additional

Indications Beyond Secondary-Progressive MS

Evaluation Criteria

Short List of

Diseases

Potential Disease

Targets off Platform

First Disease Target

NMO

•

Unmet medical need

•

Competitive landscape

•

Disease incidence

•

Single antigen immunity

•

Multiple antigen immunity

•

Likely duration of Phase 1/2 clinical trial

•

Likely cost of Phase 1/2 clinical trial

•

Clinical endpoint

•

Efficacy biomarker known

•

Animal model available

Addison’s disease

Autoimmune hemolytic anemia

Celiac  Disease

Goodpasture’s syndrome

Grave’s Disease

Hashimoto’s thyroiditis

Idiotypic thrombocytopenic purpura

Myasthenia Gravis

Neuromyelitis Optica (NMO)

Pemphigus vulgaris/foliaceus

Primary Biliary Cirrhosis

Rheumatic heart disease

Systemic lupus erythematosus

Sjögren’s syndrome

Type 1 Diabetes