Developing Well-

Differentiated Antibiotics

to Meet Medical Needs

Cempra Corporate

Presentation

Prabhavathi Fernandes, Ph.D.

President & CEO

November 2014

Forward Looking Statement

This presentation contains forward-looking statements regarding future events. These

statements are just predictions and are subject to risks and uncertainties that could cause the

actual events or results to differ materially. These risks and uncertainties include, among

others: risks related to the costs, timing, regulatory review and results of our studies and

clinical trial and those of our strategic partners; our need to obtain additional funding and our

ability to obtain future funding on acceptable terms; our anticipated capital expenditures and

our estimates regarding our capital requirements; our and our strategic partners’ ability to

obtain FDA and foreign regulatory approval of our product candidates; our dependence on the

success of solithromycin and TAKSTA; the possible impairment of, or inability to obtain,

intellectual property rights and the costs of obtaining such rights from third parties; the

unpredictability of the size of the markets for, and market acceptance of, any of our products,

including solithromycin and TAKSTA; our ability to produce and sell any approved products and

the price we are able to realize for those products; our ability to retain and hire necessary

employees and to staff our operations appropriately; our ability to compete in our industry;

innovation by our competitors; and our ability to stay abreast of and comply with new or

modified laws and regulations that currently apply or become applicable to our business.

Please refer to the documents that we file from time to time with the Securities and Exchange

Commission.

2

Highlights

Cempra has two differentiated antibiotics with broad and large commercial potential

Both in late stage of development

3

Solithromycin – Potent 4th Generation Macrolide, First

Fluoroketolide

First Oral and IV macrolide for monotherapy in CABP

Suspension for pediatrics – First in over 2 decades

Potential for broad adult and pediatric use

TAKSTA – Long History of Use in EU for Prosthetic

Joint Infections (PJI)

U.S. development for oral, chronic treatment of bone and joint infections

replacing long-term IV and multiple surgeries

Cempra’s Portfolio

4

Product Indication Formulation Preclinical Phase I Phase II Phase III Milestones

Oral

IV-to-Oral

Oral Suspension / Pediatric

Biodefense Animal Rule Oral / Suspension

Urethritis Oral

Anti-inflammatory / NASH Oral

Oral-Chronic Prosthetic Joint

Infections

Oral-ABSSSI

Oral Suspension / Pediatric

Non-Antibiotic

Macrolide Diabetic Gastroparesis and GERD

Solithromycin

(CEM-101)

Taksta

Fusidic Acid

Acute and Chronic

Treatment of MRSA

Community Acquired

Bacterial Pneumonia

New regulatory guidance, increased development efforts, increased

Pharma interest

Investing in Antibiotics Now

5

Few products approved / in development

Many are hospital intravenous use only

CDC / FDA / WHO

New laws to help antibiotic developers

Increasing antibiotic resistance to

generic drugs

Large Macrolide Market Opportunity

6

Azithromycin, a macrolide, is the most

widely prescribed treatment for CABP

and other RTIs – >60% of market

Broad spectrum of activity

Good safety

Excellent tissue/intracellular distribution and anti-inflammatory activity

Increasing resistance - 40% of U.S. pneumococci a; 96.4% in China ba Jones, RN. DMID. 2013;75:107-109; b Kim, SH. AAC. 2012;56:1418-1426..

Treatment failure of macrolide resistant pneumonia results in increased cost,

and hospital admissionHealth Policy Institute, Univ. of California, Irvine.Reynolds et al, Antimicrobial Resistance and Infection Control 2014: 3:16

51 Million prescriptions were written for azithromycin in the U.S. in 2013

2013 US Retail Antibiotic Prescriptions

Total 264 MM Annual Rxs

38.7

78.8

36.0

61.6

28.0

21.3 Cephalosporins

Beta-lactams

Fluoroquinolones

Macrolides

Other antibacterials

Tetracyclines/aminoglycosides

Source: IMS Health (Retail) AMR Hospital Data (Inpatient)

2013 IMS New Prescription Audit

Need For a New Macrolide

7

In vitro activity of solithromycin and azithromycin against 927

Streptococcus pneumoniae from RTI samples collected in 2012-2013

Morrissey, I. ECCMID 2014. Abstr. P1584.

Antibiotic RegionPercentage

MIC

(µg/mL)

S R 90%

Solithromycin

Europe (418) 100 0 0.06

NA (380) 100 0 0.25

Asia (129) 100 0 0.5

Azithromycin

Europe (418) 71.3 28.0 > 1

NA (380) 56.3 42.6 > 1

Asia (129) 28.7 70.5 > 1

8

Macrolides Have Broad Hospital & Primary

Care indications

a Source: AMR Hospital Data, IMS NPA and NDTI

0

5

10

15

20

25

30

35

CABP Bronchitis Sinusitis Gonorrhea

Days o

f T

he

rap

y

Mill

ions

Hospital Days of Therapy

~29MM days

~6MM days

~420k days ~400k days

2013 AMR Hospital Days of Therapy 2013 IMS Retail Scripts

0

5

10

15

20

25

30

35

40

Sinusitis Otitis MediaBronchitis Pharyngitis CABP

Scri

pts

Mill

ions

Retail Scripts

~34MM

~28MM ~28MM

~13MM

~10MM

RTIs: ~115 MM scripts annually

CABP and respiratory tract infections (RTIs) represent > 35MM hospital treatment days

and > 115 MM prescriptions in the communitya

Outpatient treatment failures from resistance to generic antibiotics, resulting in more and

more hospitalizations for IV therapy, risk of improperly treated infection, HAI b

A new primary care antibiotic for RTIs that is safe and effective is an urgent need

b Antimicrobial Resistance and Infection Control 2014: 3:16

What is Solithromycin?

9

Currently Approved Macrolide Antibiotics

Llano-Sotelo B, Dunkle J, Kleoacki D, Zhang W, Fernandes P,

Cate JH and Mankin AS. AAC 2010, 4961-4970

Solithromycin

- the first fluoroketolide

Binds 23S RNA at 3 regions

Solithromycin Highlights

10

Clinical Trials Phase 3 Oral, CABP completed enrollment Q3 2014, data expected Q1

2015

Phase 3 intravenous-oral switch study; enrolling

Phase 3 in gonorrhea enrolling. Phase 2 completed with 100% cure

in culture proven cases.

Phase 1 in pediatrics, enrolling

Strategic

Partnerships

BARDA HHS: $58MM contract – Development of Soli for pediatric use

and against bioterror pathogens

Toyama Chemical (FujiFilm): Global development program – exclusive

license for Japan. $20MM upfront / milestones received; up to $50MM in

additional milestones; tiered royalties based on sales

Regulatory & IP Qualified Infectious Disease Products (QIDP) granted by FDA

designations; oral and IV formulations for CABP

Provides priority review – 8 months

QIDP for gonorrhea

NCE patent to 2025 plus PTEs; Polymorph patent to 2032, and

additional patents

Community Acquired Bacterial Pneumonia (CABP) – #1 cause of death from an

infection

5 to 10 million CABP cases annually, 1.1 million patients hospitalized per yeara

─ More common in older adults (>65 years) and young children

Appropriate empiric therapy is critical to positive outcomes

Multiple pathogens can be involved - Pneumococcus – the most frequent cause

CABP – Most Frequent Infectious Disease in the U.S.

11

Pneumococcal infections cause more deaths per year in

U.S. than breast or prostate cancer.Xu, et al. Deaths: Final Data for 2007. Natl Vital Stat Rep. 2010;58:1-51.

Respiratory disease incidence is increasing;

growing numbers of COPD and asthma patientsDrug Discovery News, May 2012.

a Freeman, MK. CABP: A Primer for Pharmacists: US Pharmacist July 1, 2013

Rising Hospital Discharges for CABP

12

Source: 2011 HCUP, ARHQ.gov

CABP remains the leading cause mortality in the US

13

Safety and Efficacy Deficiencies of

Current CABP Therapies

Current IDSA/ATS recommendation to give broad spectrum, empiric coverage:

Requires intravenous cephalosporin

(e.g., ceftriaxone)

and hospitalization

Azithromycin for Legionella and

Mycoplasma

Mortality rates

in hospitalized

CABP patients

is 23%

– 30-day ratea

a Freeman, MK. US Pharmacist. July 1, 2013

Cost and hazards of HAI b Magill, SS. And CDC and Emory Authors. NEJM

2014. 1198-1208, 2014

IV and Oral available – and have broad spectrum activity,

however, they are not in favor for treating CABP because:

Treatment failures from resistant strain selection

Kill bowel flora – associated with C.difficile colitis

Adverse tendonitis, Achilles tendon rupture, hepatotoxicity and peripheral neuritis, retinal detachment

Not approved for use in pediatrics

Or

1) A β-lactam plus

a macrolide

─ No oral switch therapy

replacement

2) A fluoroquinolone

(e.g., Levaquin,

Avelox)

─ FQ treatment failure higher than

ceftriaxone plus azi a

─ Higher mortality when FQs used

without a macrolide b

─ FQs no longer used in CABP in

several countries

a Fuller, DF, Low, EL.,CID 2005. 41: 118-121b Martınez, JA., et al. CID. 2003, 36: 389-395

The only oral option is fluoroquinolone. but there is growing concern among physicians

because of safety

Solithromycin has class-leading potency & spectrum in vitro against CABP pathogens

Gram

Positive

Negative

Positive

Atypical

Atypical

Atypical

Organisms Solithromycin Azithromycin Cephalosporin Fluoroquinolone

Streptococcus

pneumoniae

Haemophilus

influenzae

Staphylococcus

aureus

Legionella

pneumophila

Mycoplasma

pneumoniae /

Chlamydophila

pneumoniae

Solithromycin – Spectrum of Activity that Addresses CABP Pathogens

14

Interacts with bacterial ribosome at three sites – Resistance rare and it could only occur if mutations occur at three distinct sites

Solithromycin Has Distinct Advantages Over Azithromycin

15

ACTIVITY

4-16 fold more active in vitro

Active against azithromycin-resistant

strains

Bactericidal for many pneumococcus

Stronger anti-inflammatory effects

PK

Best oral bioavailability

No trailing blood levels

Better intracellular activity

Better amniotic fluid and fetus exposure

TOLERABILITY / SAFETY & EFFICACY

Better tolerated (less nausea)

Safer – Negative QT, no Tinnitus

Monotherapy

DRUG STABILITY

More stable – no cladinose in

solithromycin

Ready to use IV bags in development

Ophthalmic solutions stable

Solithromycin is being developed as oral capsules, pediatric oral suspension

and intravenous formulations

Solithromycin: Phase 3 CABP Studies

NDA on 2 products: Oral capsules and Intravenous

Combined safety and efficacy data from two CABP Phase 3 studies

Both studies approximately 800 patients each

Comparator Avelox (moxifloxacin)

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Primary: Early Response ITT

Secondary: MITT

SFU 5-10 days after last dose

SOLI- Oral -5 d

SOLI IV to Oral

MOXI Oral -7 d

Primary: Early Response ITT

Secondary: MITT

SFU 5-10 days after last doseMOXI IV to Oral

Completed Enrollment –

Q3 2014

Data expected Q1 2015

Enrolling

Phase 3 Study 1: SOLITAIRE Oral

Phase 3 Study 2: SOLITAIRE IV to Oral

Bacterial Urethritis Phase 3 Trial Enrolling

Phase 3 is enrolling 300 patients with gonorrhea with or without Chlamydia

Patients receiving a single dose of solithromycin 1000 mg PO or ceftriaxone 500 mg

IM plus azithromycin 1000 mg PO

Primary efficacy endpoint – Culture negative at 7 days (TOC); secondary end point

is eradication of GC and Chlamydia, and safety and tolerability

NDA is expected to be submitted with the CABP NDA

17

Solithromycin was

100% effective in all

culture proven cases of

gonorrhea in a Phase 2

trial

1. Source: Trinity qualitative primary market research with PCPs, infectious disease specialists, pulmonologists, hospitalists, ICU intensivists, hospital

pharmacy directors and commercial payors.

Market Research1 Suggests a High Unmet

Need for a Novel Antibiotic to Treat CABP

Hospital PharmDs and inpatient physicians emphasize the lack of

options that allow patients to transition to an oral formulation of

the IV antibiotic

Products Offering

IV to Oral Step-

Down Therapy

Numerous physicians report difficulty treating patients with kidney

disease

Antibiotics for

Patients with

Kidney Disease

Respondents (80%) want a new antibiotic to overcome rising

resistance

Products to

Overcome

Increasing

Resistance

Respondents agreed that new, safe antibiotics are needed (QT

negative, not associated with C. difficile diarrhea)

Improved Safety /

Tolerability

18

Commercialization Phases

Disease awareness campaign

Profile key accounts and influencers

Segmentation to prioritize opportunity

Coming Soon ads

Introduce SOLI, establishing it as best

choice for CABP

Hospital and managed care formulary plans

Promotional Med Ed campaign

Continue to build brand awareness

Promotional campaign aligned to new indications

Expanded physician specialty reach

PRE-LAUNCH

LAUNCH

EXPANDED

RTI’s and

Other

Indications

ONGOING

AT

APPROVAL

POST-

APPROVAL

19

Solithromycin’s Broad Use Potential

20

HAP, Simple RTI’s, Pharyngitis, Sinusitis, Bronchitis,

Acute Exacerbation of Chronic Bronchitis (AECB)

Respiratory Tract Infections (RTI)

Antibacterial and Anti-inflammatory

COPD, Cystic fibrosis, Panbronchiolitis, NASHSpecial

PopulationsBARDA funded Pediatrics and Pregnancy

No pediatric drug with broad potential

in development

Infections in pregnancy – neonatal sepsis

Infections In Utero – Premature, Cerebral palsy, Autism

BiodefenseBARDA funded

Multiple Unidentified PathogensAnthrax, Tularemia

Sexually

Transmitted

Diseases

Genital Infections (Gonorrhea and Chlamydia)

Major public health crisis – multi drug resistance, no oral

therapy

GI & Others

OphthalmicHelicobacter gastritis, Campylobacteria, tick and insect

borne diseases, diarrhea, and ophthalmic drops

CABP

Primary

Indication

Other Infections

TAKSTA™ (Fusidic Acid)

21

An Oral Antibiotic for MRSA Infections Being Developed for Chronic Use in

Bone and Joint Infections in the U.S.

What is Taksta? Cempra’s proprietary fusidic acid dosing regimen

40 years of safety and efficacy in acute and chronic oral use in staph

infections (including MRSA) ex-U.S.

Unique structure, no known cross resistance with any other antibiotic

Clinical Trials Phase 2 PJI study data reported, study stopped

The pivotal study is being discussed with FDA

Regulatory Orphan Drug Designation for PJI granted by FDA (October 2013)

Orphan Drug designation benefits

7 - year exclusivity

Tax credit for 50% of clinical trial cost

and PDUFA fees exempted

GAIN pathogen MRSA-Potential QIDP

Intellectual

Property

Loading dose patent into 2029 and PTEs

Well tolerated in ABSSSI Phase 2 study;

no resistance seen

Taksta Highlights

22

0

20

40

60

80

100

120

European dosing

Cempra’s loading dose

0 24 48 72 96 120

Time (hrs)

EU Dose 500 mg dose

Cempra dose 1200 mg Q12h Day followed by 600 mg Q12h

Concentr

ation (

mg/L

)

Total Joint and Hardware Procedures – 3,286,000/yeara,b

200,000 Hip Replacements; 550,000 Knee Replacements in 2007*

1% of hips and 2% of knees develop PJI's**Del Pozo J.L. & Patel R. NEJM 361: 787794, 2009

Potential use in osteomyelitis, septic arthritis, and diabetic foot

TAKSTA for Chronic Oral Use in Bone and Joint Infections

Compassionate use cases of bone/prosthesis infections in North America

23

a Life Science Intelligence market research report. U.S. Markets for Large Replacement Technologies in 2012. March, 2012.

b Life Science Intelligence market research report. U.S. Markets for Small Joint Implants and Hardware for the Extremities. January, 2012.

Phase 2 study, Stopped April 2014. Phase 3 meeting with FDA expected in Q4 2014

Achieved and Projected Milestones

1Q 14: QIDP designation by FDA for solithromycin for gonorrhea

1Q 14: Negative QT results for solithromycin

1Q 14: Pediatric trial initiated for solithromycin

2H 14: Initiated Phase 3 gonorrhea study for solithromycin

3Q 14: Enrollment completed, Phase 3 oral for solithromycin

4Q 14: Meet with FDA to define pivotal study for Taksta

4Q 14: Initiate Phase 2 COPD study for solithromycin

1Q 15: Data expected SOLITAIRE Oral Phase 3 CABP

24

Cash & Equivalents (9/30/14) $74.2MM

Long-Term Debt (9/30/14) $18.1MM

Shares Outstanding (10/24/14) 35.8MM

Capitalization

25

Gary Horwith, MD

EVP Regulatory

David Moore, MBA

CCO

Mark Hahn, CPA

CFO

David Oldach, MD

SVP ClinicalGILEAD

Prabhavathi Fernandes, PhD

President & CEO

David Pereira, PhD

SVP Chemistry

Azactam (aztreonam)

Biaxin (clarithromycin)

Dificid (fidaxomicin)

Levaquin

Topamax

Ultram

Nucynta

Proven Management Team

26

IPO and M&A

Athenix-Bayer CropScience

Charles & Colvard (CTHR)

E&Y

S. aureus vaccine

Abelcet

Viread

GS-9190

Combinations against HCV

Injectable penicillins

Dobutamine HCl injection

Ranitidine injection

Take Away Notes

27

Cempra has two differentiated antibiotics in clinical development

Solithromycin is a next generation macrolide being developed as adult oral,

intravenous and pediatric formulations

– Available in oral capsules / powder for suspension / Intravenous

Late-stage clinical development - Enrollment in the oral Phase 3 trial

completed, data expected 1Q 2015

Cash sufficient, based on current assumptions, to run current operations into

2016