2017 business decision to cease GEN-003 spending.

The main purpose of this clinical study is to see if a maintenance dose of GEN-003 reduces the number of days that subjects have a genital herpes recurrence. The second purpose of the study is to evaluate the safety and tolerability of a maintenance dose of GEN-003.

This study is a randomized, double-blind, placebo-controlled clinical trial of GEN-003 in subjects who have received previous doses of GEN-003 in the GEN-003-003 clinical trial. Eligible subjects will be randomized in a 1:1 ratio to receive 1 intramuscular (IM) dose (the maintenance dose) of GEN-003 or placebo.

Subjects will use a daily electronic reporting tool for reporting the presence or absence of genital herpes lesions, and severity of genital herpes symptoms.

GEN-003-005 was originally designed to follow subjects for 12 months after the maintenance dose but a business decision, unrelated to product safety, was made by Genocea Biosciences in 3Q2017 to cease GEN-003 spending and activities.

Inclusion Criteria:

• Completed Study GEN-003-003
• Received all 3 GEN-003 doses (any dose combination) in Study GEN-003-003
• Received last dose of GEN-003 within 11 to 18 months prior
• Reported data in the daily electronic reporting period on at least 80% of days in Study GEN-003-003
• Collected at least 45 swabs (of 56 total expected swabs) during the Month 11 to 12 swab collection period in Study GEN-003-003
• Willing and able to provide written informed consent
• Willing to perform and comply with all study procedures
• Postmenopausal or willing to practice a highly effective method of contraception for 28 days before and 90 days after enrollment

Exclusion Criteria:

• Did not meet all eligibility criteria in Study GEN-003-003, or received incorrect treatment in Study GEN-003-003
• Use of suppressive antiviral medication within 14 days prior
• Use of topical steroids or antiviral medication in the anogenital region within 14 days prior
• Use of tenofovir, lysine, or other medication or supplement known or purported to affect HSV recurrence frequency or intensity within 14 days prior
• History of any form of ocular HSV infection, HSV-related erythema multiforme, or herpes meningitis or encephalitis
• Immunocompromised individuals
• Diagnosis or suspicion of an AESI
• Diagnosis or suspicion of any other autoimmune disease not listed in Appendix 4 of the protocol
• Vaccine-related SAE in GEN-003-003
• Known current infection with HIV or hepatitis B or C virus
• History of hypersensitivity to any component of the vaccine
• Prior receipt of another vaccine containing HSV-2 antigens other than GEN-003
• Receipt of any IP within 30 days prior to the maintenance dose of GEN-003/placebo
• Receipt of any blood product within 90 days prior to the maintenance dose
• Receipt of a live vaccine within 28 days prior to or any other vaccine within 14 days prior to maintenance dose
• Planned use of any vaccine from the maintenance dose to 28 days after the maintenance dose
• Pregnant or nursing women
• History of drug or alcohol abuse
• Other active, uncontrolled comorbidities
• Changes to medication used to manage an underlying comorbidity within 60 days prior

Local reactions and systemic events were systematically collected for 7 days after the maintenance dose. AEs were recorded for 12 months of followup after the maintenance dose administration.

Systematic AE results for the placebo group are based on 16 subjects since one subject who withdrew from the study did not report local reactions and systemic events data.

Small numbers of enrolled subjects likely led to a lack of statistical power. After a 2017 business decision to cease GEN-003 spending, the outcome measures were reduced to 6 months of follow up, rather than the originally planned 12 months.