Eleven Biotherapeutics Granted U.S. Composition-of-Matter Patent for EBI-005

Eleven Biotherapeutics, Inc. (Nasdaq: EBIO), a clinical-stage biopharmaceutical company discovering and developing protein therapeutics to treat diseases of the eye, today announced the issuance of U.S. Patent No. 8,853,150 entitled "Chimeric Il-1 Receptor Type I Agonists and Antagonists." This patent covers the composition-of-matter of Eleven’s lead product candidate, EBI-005, a topically-administered interleukin-1 (IL-1) receptor blocker, certain other compositions that are IL-1 receptor antagonists, and related methods for treating ocular surface inflammatory diseases, such as dry eye disease and allergic conjunctivitis. Designed, engineered and generated using Eleven’s AMP-Rx platform, EBI-005 is being developed as a topical protein therapeutic for ocular diseases. Eleven recently reported top-line results of a Phase 2 study of EBI-005 in patients with moderate to severe allergic conjunctivitis and is currently evaluating EBI-005 in a pivotal Phase 3 clinical study in patients with dry eye disease, with top-line data expected in early 2015.

“This patent, which will expire in 2031, contains both composition-of-matter and methods of use claims and strengthens our intellectual property portfolio for EBI-005,” said Abbie Celniker, Ph.D., President and Chief Executive Officer. “We were pleased with the recently announced results of our Phase 2 clinical study of EBI-005 in patients with allergic conjunctivitis and look forward to reporting top-line, pivotal Phase 3 data in dry eye disease in early 2015.”

About EBI-005

Eleven Biotherapeutics’ most advanced product candidate is EBI-005, a novel, topically-administered interleukin-1 (IL-1) receptor blocker in development as a protein therapeutic for dry eye disease and allergic conjunctivitis. The EBI-005 program is based on the role that elevated levels of the inflammatory cytokine IL-1 play in the initiation and maintenance of the inflammation and pain associated with dry eye disease and the redness, itching and other symptoms associated with allergic conjunctivitis. EBI-005 has been evaluated in a Phase 2 study in patients with moderate to severe allergic conjunctivitis and is currently being evaluated in a pivotal Phase 3 study in dry eye disease.

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. For more information, please visit Eleven's web site at www.elevenbio.com.

Cautionary Note on Forward-Looking Statements

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 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 quarterly report on Form 10-Q filed with the Securities and Exchange Commission on August 13, 2014 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.