News Release

HSV-2 vaccine shows significant clinical symptoms & viral shedding reductions at 6 months

Genocea's therapeutic vaccine results for ongoing Phase 1/2a study presented at World Vaccine Congress

Business Announcement

Linnden Communications

CAMBRIDGE, MA, March 24, 2014: Updated Phase 1/2a results with GEN-003, a vaccine candidate under development by Genocea Biosciences, Inc. (Nasdaq: GNCA) for the treatment of herpes simplex virus type 2 (HSV-2) infection, showed the experimental vaccine to generate highly significant reductions in both the number of clinical lesion days and rate of viral shedding at six months after the final vaccine dose. Genocea, a company pioneering novel T cell vaccines and immunotherapies, reported the results from the ongoing trial of GEN-003 today as an oral presentation at the World Vaccine Congress, being held March 24-26 in Washington, DC.

The ongoing Phase 1/2a double-blind, placebo-controlled study showed that patients treated with GEN-003 at the 30 microgram dose level experienced a 72 percent reduction in lesion days six months after study initiation compared to baseline levels (p<0.001). The results expand upon the positive initial data reported as a late breaker at ICAAC in September 2013 showing that patients treated at the 30 microgram dose level experienced a 50 percent reduction in mean viral shedding from baseline (p<0.001) immediately following three doses, which was maintained at six months (p<0.001). Treatment with GEN-003 was well tolerated overall.

"HSV-2 is an incurable sexually transmitted disease that affects over 500 million people worldwide, and current oral drugs require costly, inconvenient daily dosing to optimally control the painful symptoms of HSV-2 outbreak or to block viral transmission to other individuals," said Jessica Baker Flechtner, PhD, Genocea senior vice president of research, who presented the data. "This is the first time an HSV-2 immunotherapy has shown a significant impact on clinical symptoms, and the fact that GEN-003 has shown durable results six months after study initiation is very encouraging. Results of this initial clinical study of GEN-003, if confirmed by further clinical testing, suggest a compelling best-in-class profile for this therapeutic vaccine against HSV-2 infection, that may lead to reductions in both disease transmission and recurrent disease outbreaks."

"These exciting results support the ability of GEN-003 to provide a durable reduction in clinical symptoms, and validate the ATLAS™ platform as a tool for the rational discovery and development of novel vaccines and immunotherapies," said Chip Clark, president and chief executive officer of Genocea. "We expect to announce twelve-month data from this study in mid-2014, and also plan to initiate additional Phase 2 testing of GEN-003 in 2014 to further optimize dosing."

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About GEN-003

GEN-003 is Genocea's lead vaccine candidate designed with insights from Genocea's ATLAS™ antigen discovery platform, which identifies vaccine targets by profiling the T cell responses to a pathogen in large populations of humans exposed to that pathogen. GEN-003 is a first-in-class T cell vaccine candidate intended to reduce the transmission risk and clinical symptoms of HSV-2 by inducing a balanced B cell (antibody) and T cell immune response which is believed to be critical to achieving a long-term control of HSV-2. GEN-003 includes fragments of ICP4 and gD2 antigens, as well as the proprietary adjuvant, Matrix-M™, licensed from Novavax, Inc. The adjuvant is a novel saponin-derived product that has demonstrated a B and T cell immunostimulatory profile in previous clinical studies. For more information about GEN-003, please visit http://www.genocea.com/platform-pipeline/pipeline/gen003-for-hsv-2/.

About the GEN-003 Phase 1/2a Clinical Trial

The ongoing Phase 1/2a clinical trial is a double-blind, placebo-controlled, dose-escalation study to evaluate the safety and immunogenicity of GEN-003. The study enrolled 143 volunteers with a history of moderate-to-severe recurrent HSV-2 infection at seven clinics in the United States. Patients were sequentially enrolled into 1 of 3 dose cohorts (10, 30 or 100 micrograms of each protein) and randomized within cohorts to receive either GEN-003, vaccine antigens without adjuvant or placebo. Patients received three injections of the assigned treatment into an arm muscle at 21 day intervals, and are being followed for 1 year after the third injection. For more information about this clinical study of GEN-003 please visit http://www.clinicaltrials.gov.

About Genocea Biosciences, Inc.

Genocea is harnessing the power of T cell immunity to develop the next generation of vaccines and immunotherapies. T cells are increasingly recognized as a critical element of protective immune responses to a wide range of diseases, but are difficult to target using traditional discovery methods. Genocea is able to identify protective T cell antigens in humans exposed to a pathogen using ATLAS™, its proprietary technology platform, potentially enabling vaccines against pathogens for which vaccine solutions do not exist or are sub-optimal. Genocea's pipeline of novel clinical stage T cell enabled vaccines includes GEN-003 for HSV-2 therapy, GEN-004 to prevent infections caused by pneumococcus, and earlier-stage programs in chlamydia, HSV-2 prophylaxis, malaria and cancer immunotherapy. For more information, please visit the company's website at http://www.genocea.com.

Forward Looking Statement-

Statements herein relating to future business performance, conditions or strategies and other financial and business matters, including expectations regarding clinical developments, are forward-looking statements within the meaning of the Private Securities Litigation Reform Act. Genocea cautions that these forward-looking statements are subject to numerous assumptions, risks and uncertainties, which change over time. Factors that may cause actual results to differ materially from the results discussed in the forward-looking statements or historical experience include risks and uncertainties, including Genocea's ability to progress any product candidates in preclinical or clinical trials; the scope, rate and progress of its preclinical studies and clinical trials and other research and development activities; clinical trial results; current results may not be predictive of future results; even if the data from preclinical studies or clinical trials is positive, the product may not prove to be safe and efficacious; Genocea's ability to enter into future collaborations with industry partners and the government and the terms, timing and success of any such collaboration; the cost of filing, prosecuting, defending and enforcing any patent claims and other intellectual property rights; our ability to obtain rights to technology; competition for clinical resources and patient enrollment from drug candidates in development by other companies with greater resources and visibility; our ability to obtain adequate financing in the future through product licensing, co-promotional arrangements, public or private equity or debt financing or otherwise; general business conditions; competition; business abilities and judgment of personnel; and the availability of qualified personnel. Further information on the factors and risks that could affect Genocea's business, financial conditions and results of operations is contained in Genocea's filings with the U.S. Securities and Exchange Commission, which are available at http://www.sec.gov. These forward-looking statements speak only as of the date of this press release and Genocea assumes no duty to update forward-looking statements.

Genocea routinely posts information that may be significant to investors in the Investor Relations section of its website, and encourages investors to consult that section regularly. For additional information, please visit http://www.genocea.com.


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