Eleven Biotherapeutics Presents Data on EBI-031 for the Treatment of Diabetic Macular Edema at ARVO 2015 Annual Meeting

Eleven Biotherapeutics, Inc. (NASDAQ: EBIO), a clinical-stage biopharmaceutical company discovering and developing protein therapeutics to treat diseases of the eye, today announced the presentation of data for EBI-031, its novel, protein therapeutic IL-6 inhibitor in preclinical development for diabetic macular edema, at the Association for Research in Vision and Ophthalmology (ARVO) 2015 Annual Meeting. These preclinical pharmacokinetic studies with EBI-031, which have been optimized for intravitreal administration using Eleven’s AMP-Rx technology, confirmed the ability of EBI-031 to potently inhibit IL-6 signaling with extended vitreal retention compared to existing therapies. The Company plans to file an investigational new drug (IND) application with the U.S. Food and Drug Administration (FDA) by the end of 2015 for clinical development of EBI-031 in diabetic macular edema.

“We are very encouraged by this preclinical pharmacokinetic data demonstrating that we have successfully achieved the important design criteria necessary for an intravitreal IL-6 antagonist and supporting our development plans for EBI-031 in diabetic macular edema,” said Abbie Celniker, PhD, President and Chief Executive Officer of Eleven Biotherapeutics. “Based on these data, including potent inhibition of IL-6 signaling, extended vitreal retention compared to existing therapies and rapid systemic clearance, we plan to file an IND application with the FDA by the end of 2015 for clinical development of EBI-031 in diabetic macular edema.”

In a poster presentation entitled, “Optimized Intravitreal IL-6 Antagonist for the Treatment of Diabetic Macular Edema,” Eleven Biotherapeutics researchers describe the preclinical data demonstrating that EBI-031 has successfully achieved key design criteria and optimized drug-like properties necessary for an intravitreal IL-6 antagonist including potent blockade of IL-6 signaling, and pharmacokinetics properties such as extended vitreal retention and rapid systemic clearance. Highlights of the poster include:

• Potent blockade of both bound (IL-6/sIL-6Rα complex trans-signaling) and free IL-6 (cis-signaling)
  • EBI-031 blocks free IL-6 (cis-signaling) >900 fold more potently than standard of care tocilizumab and unlike tocilizumab, potently inhibits hyper IL-6, a genetic fusion of the IL-6/sIL-6Rα trans-signaling complex
• Slow vitreal clearance compared to existing therapies to support monthly or greater frequency of dosing
  • EBI-031 cleared in approximately 10 days compared to aflibercept at approximately 6 days and tocilizumab at approximately 5 days in pharmacokinetic studies performed in New Zealand white rabbits injected IVT bilaterally
• Rapid systemic clearance and low systemic accumulation of molecules that escape the eye to minimize toxicity
  • Following IV administration in rabbits, EBI-031 is cleared from systemic circulation approximately two times faster than aflibercept, or tocilizumab, and demonstrated lower systemic accumulation than these agents
• Extended duration of EBI-031 blockade through predictive modeling
  • Due to its high potency and long vitreal retention, EBI-031 is predicted to inhibit 95% of IL-6 signaling for >100 days following a single 50 mg/mL IVT injection in humans compared to 10 days for tocilizumab or 60 days for aflibercept
• Efficient penetration of ocular tissues
  • EBI-031 molecule detected at high levels in the aqueous, choroid, and retina following IVT administration.

About EBI-031

Eleven Biotherapeutics’ most advanced preclinical product candidate is EBI-031 for treatment of diabetic macular edema, or DME. EBI-031 has been designed and engineered for intravitreal delivery using our AMP-Rx platform. EBI-031 is a potent blocker of both free IL-6 and IL-6 complexed to the soluble IL-6 receptor (IL-6R) and has demonstrated a longer vitreal retention time in preclinical models than antibodies and antibody-like molecules approved for intravitreal injection. We are undertaking the necessary manufacturing development work and nonclinical safety studies to support the submission of an investigational new drug application, or IND, to the FDA by the end of 2015 for the purpose of conducting clinical trials of EBI-031 in DME.

About Eleven Biotherapeutics

Eleven Biotherapeutics, Inc. is a clinical-stage biopharmaceutical company with a proprietary protein engineering platform, called AMP-Rx, that it applies to the discovery and development of protein therapeutics to treat diseases of the eye. Eleven’s therapeutic approach is based on the role of cytokines in diseases of the eye, the company’s understanding of the structural biology of cytokines and the company’s ability to rationally design and engineer proteins to modulate the effects of cytokines. Cytokines are cell signaling molecules found in the body that can have important inflammatory effects.

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Any statements in this press release about future expectations, plans and prospects for the Company, including statements about the Company's strategy, future operations, advancement or maturation of its product candidates and product pipeline, clinical development of the Company's therapeutic candidates, including expectations regarding timing of initiation of clinical trials, patient enrollment and availability of results, regulatory requirements for initiation of clinical trials and registration of product candidates, sufficiency of cash resources and other statements containing the words "anticipate," "believe," "estimate," "expect," "intend," "may," "plan," "predict," "project," "target," "potential," "will," "would," "could," "should," "continue," and similar expressions, constitute forward-looking statements within the meaning of The Private Securities Litigation Reform Act of 1995. Actual results may differ materially from those indicated by such forward-looking statements as a result of various important factors, including: the uncertainties inherent in the initiation and conduct of clinical trials, availability and timing of data from ongoing clinical trials, whether results of early clinical trials will be indicative of the results of future trials, the adequacy of any clinical models, uncertainties associated with regulatory review of clinical trials and applications for marketing approvals and other factors discussed in the "Risk Factors" section of the Company's most recent quarterly report on Form 10-Q filed with the Securities and Exchange Commission on April 30, 2015 and other reports on file with the Securities and Exchange Commission. In addition, the forward-looking statements included in this press release represent the Company's views as of the date hereof. The Company anticipates that subsequent events and developments will cause the Company's views to change. However, while the Company may elect to update these forward-looking statements at some point in the future, the Company specifically disclaims any obligation to do so. These forward-looking statements should not be relied upon as representing the Company's views as of any date subsequent to the date hereof.