Genocea Announces Positive Top-Line Phase 2 Data for Genital Herpes Immunotherapy GEN-003

- Highly statistically significant 55 percent reduction in viral shedding rate with best dose -
- Company to host conference call at 9 a.m. EDT today including guest speaker Peter A. Leone, MD -

CAMBRIDGE, Mass.-- Genocea Biosciences, Inc. (GNCA), a biopharmaceutical company developing T cell-directed vaccines and immunotherapies, today announced positive top-line data from a Phase 2 dose optimization trial evaluating GEN-003 for the treatment of genital herpes. During the 28-day observation period immediately after completion of dosing, the best dose of 60 µg per protein / 75 µg of Matrix-M2^TM adjuvant demonstrated a highly statistically significant (p<0.0001) 55 percent reduction from baseline in the viral shedding rate, the primary endpoint of the trial and a measure of anti-viral activity. All dose combinations tested, including the successful 30 µg per protein / 50 µg of adjuvant dose from the prior Phase 1/2a trial, demonstrated a statistically significant viral shedding rate reduction versus baseline and only the lowest dose combination did not demonstrate a statistically significant reduction versus placebo.

In a planned secondary analysis to assess impact on patient-reported genital lesion rates, a self-assessed measurement of clinical disease, all dose groups, including the placebo group, demonstrated a statistically significant reduction from baseline.

“We are extremely pleased with these positive top-line results which have successfully allowed us to identify the optimal dose to advance into further trials,” said Chip Clark, president and chief executive officer. “The results strengthen the product profile from our Phase 1/2a trial, which we have shown in market research to be highly clinically meaningful and commercially attractive, providing further evidence of the strong value proposition of GEN-003 for patients, physicians and payers.”

The Phase 2 study showed that GEN-003 was generally safe and well tolerated by patients, with no serious adverse events related to the vaccine. Safety data throughout the trial is monitored by an independent data safety monitoring board. Although reactogenicity increased with adjuvant dose, there was no difference in discontinuations in patient dosing due to adverse events across the different treatment arms.

“People living with genital herpes are seeking treatments that deliver on efficacy and provide them with peace of mind that they are at less risk of transmitting the infection to their sexual partners,” said Peter Leone, MD, Professor of Medicine and Adjunct Professor of Epidemiology at the University of North Carolina, and an investigator in the GEN-003 dose optimization trial. “We know that asymptomatic viral shedding is the driver of herpes transmission and GEN-003’s demonstrated antiviral efficacy data reported to date suggest this immunotherapy can be an effective future treatment.”

About the GEN-003 Phase 2 Clinical Trial

The Phase 2 study enrolled 310 subjects from 17 institutions in the United States. Subjects were randomized to one of six dosing groups of either 30 µg or 60 µg per protein paired with one of three adjuvant doses (25 µg, 50 µg, or 75 µg). A seventh group received placebo. Subjects received three doses of GEN-003 or placebo at 21-day intervals. Baseline viral shedding and genital lesion rates were established for each subject in a 28-day observation period prior to the commencement of dosing by collecting 56 genital swab samples (two per day), which were analyzed for the presence of HSV-2 DNA, and by recording the days on which genital lesions were present. This 28-day observation period was repeated immediately after the completion of dosing and will be repeated two more times over the course of this trial, at six and twelve months following dosing. No booster doses will be given.