Data show immune responses occur rapidly after only two vaccinations and can be sustained for more than one year

Part B is exploring the vaccine's ability to reduce tumor size beyond the standard-of-care therapy alone

CAMBRIDGE, Mass., May 29, 2020 (GLOBE NEWSWIRE) -- Genocea Biosciences, Inc. (GNCA), a biopharmaceutical company developing next-generation neoantigen immunotherapies, today presents updated durability, safety and immunogenicity clinical data from Part A of its ongoing Phase 1/2a trial for GEN-009, the company’s lead neoantigen vaccine candidate. Data will be shared by Roger Cohen, M.D., University of Pennsylvania Abramson Cancer Center, during a video poster presentation (Abstract #3107) at the virtual 2020 American Society of Clinical Oncology (ASCO) Annual Meeting on May 29, 2020 from 8:00 – 11:00 am EDT.

ASCO POSTER SESSION: Developmental Therapeutics – Immunotherapy
Abstract 3107

Title: GEN-009, a neoantigen vaccine containing ATLAS-selected neoantigens, to generate broad sustained immunity against immunogenic tumor mutations and avoid inhibitory peptides.

The analysis evaluates eight patients from Part A of the trial who were vaccinated with GEN-009 as adjuvant therapy, focusing on the onset and duration of induced immunity and clinical outcomes. Seven out of the eight patients enrolled have continued without progression with a median follow up of over one year. All patients received dosing as planned, with five doses given over a six-month period with immune responses occurring rapidly after only two vaccinations. No significant adverse side effects were reported with the administration of GEN-009, with only mild symptoms associated with the vaccine adjuvant. In addition, there are several notable patient outcomes:

• Prior to the GEN-009 trial, one patient diagnosed with melanoma (low PDL-1) had progressed after treatment with a PD-1 antibody, an experimental vaccine and a CTLA-4 inhibitor. After GEN-009, the patient continues in remission for more than 12 months.

• A patient diagnosed with squamous cell cancer of the head and neck had experienced successively shorter remissions but is now exceeding previous remissions and approaching nine months progression free with GEN-009.

“The fact that seven of eight patients continue without progression is encouraging. The vaccine has been well tolerated with only mild injection site reactions. Vaccinated patients have generated both CD4⁺ and CD8⁺ ex vivo immune responses with immunogenicity manifested to 99% of the vaccinated antigens,” said Dr. Cohen.

Both CD8⁺ and CD4⁺ responses were measured in both ex vivo and in vitro assays and were detected as early as day 29 extending as far as 12 months.