(CEMP) Initiates Phase 3 Clinical Trial of Taksta in Skin Infections

Pivotal Trial Designed to Demonstrate Non-Inferiority of Taksta Compared to Oral Zyvox(R) (linezolid)

CHAPEL HILL, N.C., Dec. 8, 2015  — Cempra, Inc. (Nasdaq:CEMP), a clinical-stage pharmaceutical company developing antibiotics to meet critical medical needs in the treatment of bacterial infectious diseases, today announced that the first patient has been dosed in its Phase 3 clinical trial to evaluate the safety and efficacy of oral Taksta™ (CEM-102, sodium fusidate, the sodium salt of fusidic acid) as a potential treatment for acute bacterial skin and skin structure infections (ABSSSI). Cempra is developing Taksta exclusively in the United States as an oral treatment for ABSSSI and refractory bone and joint infections.

“Initiation of this Phase 3 trial for Taksta in ABSSSI marks an important milestone for this program, for our company and for the patients who suffer from these types of serious infections,” said Prabhavathi Fernandes, Ph.D., president and chief executive officer of Cempra. “In addition, we plan to initiate an exploratory trial for Taksta early next year in patients with refractory bone or joint infections. We believe increasing rates of bacterial resistance support the development of additional antibiotics and that Taksta, if approved, may provide an important treatment option for certain patient populations.”

Phase 3 Clinical Trial Design

The Phase 3 clinical trial is designed to evaluate the efficacy and safety of Taksta in the treatment of ABSSSI. Approximately 712 patients, 12 years old and up and diagnosed with ABSSSI, will be randomized one to one to receive either Taksta or Zyvox (linezolid). The primary objective is to demonstrate non-inferiority of Taksta compared to Zyvox for early clinical response (ECR) defined as the proportion of patients alive and achieving a ≥ 20% reduction from baseline in lesion size at 48-72 hours after start of study drug. Patients randomized to treatment with Taksta will receive 1500 mg by mouth every 12 hours for 2 doses, followed by 600 mg by mouth every 12 hours thereafter, until the end of therapy (10 days total). Patients randomized to the active comparator, linezolid, will be dosed with oral 600 mg every 12 hours for 10 days. Secondary outcome measures will assess the proportion of subjects with clinical success at their post-treatment evaluation 7 to 14 days after the end of treatment in the intent to treat and clinically evaluable patient groups. The incidence of adverse events will be recorded and clinical laboratory evaluations will be conducted. The design of this study conforms to FDA guidelines for conducting clinical trials in ABSSSI published in October 2013.

In September 2015, the FDA granted qualified infectious disease product (QIDP) designation to Taksta oral tablets for the indication of ABSSSI. The QIDP designation provides certain incentives for the development of new anti-infectives, including eligibility for priority review, the FDA’s Fast Track program, and a potential five-year extension of exclusivity under the Hatch-Waxman Act.

About Taksta™

Cempra is developing Taksta (CEM-102, sodium fusidate, the sodium salt of fusidic acid) exclusively in the U.S. for acute bacterial skin and skin structure infections (ABSSSI) and is exploring its use for the long term oral treatment for refractory bone and joint infections. Fusidic acid is orally active against gram-positive bacteria, including all Staphylococcus aureus strains such as healthcare-acquired methicillin-resistant Staphylococcus aureus (HA-MRSA) and community-acquired (CA) MRSA. Taksta previously successfully completed a Phase 2 clinical trial in patients with ABSSSI, which is frequently caused by MRSA, demonstrating a tolerability profile and efficacy comparable to linezolid (sold under the brand name Zyvox®), the only oral antibiotic with FDA approval for the treatment of MRSA. A Phase 2 trial in patients with primarily staphylococcal infections of prosthetic hip and knee joints demonstrated that fusidic acid in combination with rifampin was generally comparable to intravenous standard of care antibiotics.

About Cempra, Inc.

Cempra, Inc. is a clinical-stage pharmaceutical company focused on developing antibiotics to meet critical medical needs in the treatment of bacterial infectious diseases. Cempra’s two lead product candidates are currently in advanced clinical development. Solithromycin (CEM-101) has successfully completed two Phase 3 clinical trials for community-acquired bacterial pneumonia (CABP) and is licensed to strategic commercial partner Toyama Chemical Co., Ltd., a subsidiary of FUJIFILM Holdings Corporation, for certain exclusive rights in Japan. Solithromycin is also in a Phase 3 clinical trial for uncomplicated bacterial urethritis caused by Neisseria gonorrhoeae and chlamydia. Cempra is contracted with BARDA for the development of solithromycin for pediatric use. Three formulations, intravenous, oral capsules and a suspension formulation are in a Phase 1b trial in children from birth to 17 years of age. Taksta™ is Cempra’s second product candidate, which is being developed for acute bacterial skin and skin structure Infections (ABSSSI) and is also expected to be tested in an exploratory study for chronic oral treatment of refractory infections in bones and joints. Both products seek to address the need for new treatments targeting drug-resistant bacterial infections in the hospital and in the community. Cempra has also synthesized novel macrolides for non-antibiotic uses such as the treatment of chronic inflammatory diseases, endocrine diseases and gastric motility disorders. Cempra was founded in 2006 and is headquartered in Chapel Hill, N.C. For additional information about Cempra please visit www.cempra.com.

Please Note: This press release 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: the costs, sources of funds, enrollment, timing, regulatory review and results of our studies and clinical trials and those of our strategic commercial partners; our and our strategic commercial partners’ ability to obtain FDA and foreign regulatory approval of our product candidates; our ability to commercialize and launch, whether on our own or with a strategic partner, any product candidate that receives regulatory approval; the costs, sources of funds, timing, regulatory review and results of our studies and clinical trials and those of our strategic commercial 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; 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; the possible impairment of, or inability to obtain, intellectual property rights and the costs of obtaining such rights from third parties; our ability to compete in our industry; our dependence on the success of solithromycin and Taksta; 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. The reader is referred to the documents that we file from time to time with the Securities and Exchange Commission.

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         Robert H. Uhl
         Westwicke Partners, LLC
         (858) 356-5932
         robert.uhl@westwicke.com

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         Tony Plohoros
         6 Degrees
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