Genocea Biosciences, Inc. Presents Promising Long-Term Results from Gen-009 Neoantigen Vaccine Phase 1 Trial At Asco 2021
June 04, 2021 at 09:00 am EDT
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Genocea Biosciences, Inc. presents updated immunogenicity and clinical response data from the GEN-009 Phase 1 trial that continue to validate the company’s unique and differentiated approach to identifying clinically meaningful immunotherapy targets through the proprietary ATLAS selection process. Long-term results demonstrate that GEN-009 continues to generate broad immune responses against neoantigens that can lead to sustained clinical responses. In Part A of the study, designed to measure safety and immunogenicity only, eight patients with no measurable disease were vaccinated with GEN-009 as a monotherapy. Six of the eight patients continue without recurrence with a median follow up of 25 months post start of the vaccination. Notably, as previously reported, GEN-009 elicited T cell immune responses to 99% of the ATLAS-selected neoantigens, the seen across neoantigen vaccine programs. In Part B, patients were enrolled at the initiation of a PD-1 checkpoint inhibitor (CPI)-based standard of care (SOC) regimen for advanced or metastatic disease; patients who were controlled on SOC and did not require alternate therapy are labeled CPI-sensitive, patients who required alternate therapy before vaccination are labeled CPI-refractory. Of the nine CPI-sensitive patients, the latest data show four patients experienced novel reduction in tumor volume post-GEN-009 dosing and achieved independent RECIST responses after vaccination, including three partial responses (PRs) and one complete response (CR). This is an increase from the two PRs and one CR previously reported at SITC 2020. The remaining five CPI-sensitive patients all achieved disease stabilization. Across the CPI-sensitive cohort, the median duration without disease progression after initial GEN-009 vaccination was 15 months. Of the seven CPI-refractory patients, two achieved stable disease after initial GEN-009 vaccination for up to 10 months. GEN-009 has been well tolerated with only mild adverse events associated with the vaccine adjuvant. Expanded immunogenicity data from Part B of the study revealed that vaccine-specific T cell responses were detected ex vivo after the first dose of the vaccine and continued to rise with each subsequent dose. Vaccine-specific T cell responses remained significantly elevated over baseline and post-CPI, pre-vaccine timepoints for at least 6 months, showing persistence of the vaccine response. CPI-sensitive subjects had a greater number of neoantigens identified with ATLAS at baseline compared with patients in the CPI-refractory cohort, and also had evidence of epitope spread for CD8+ T cells post-dosing. Additionally, the magnitude of CD4+ T cell responses were greater for the CPI-refractory than CPI-sensitive subjects, despite a reduced proportion of peptides to which CD4+ T cell responses were measured, suggesting that the breadth and not the magnitude of response could be associated with favorable outcomes.
Genocea Biosciences, Inc. is a biopharmaceutical company. The Company is engaged in discovering and developing cancer immunotherapies using its proprietary ATLAS platform. The ATLAS platform can profile each patient's CD4+ and CD8+ T cell immune responses to every potential target or antigen identified by next-generation sequencing of that patient's tumor. ATLAS zeroes in on both antigens that activate anti-tumor T cell responses and inhibitory antigens, or Inhibigens, that drive pro-tumor immune responses. Its GEN-009 is an investigational neoantigen vaccine delivering adjuvanted synthetic long peptides from ATLAS-identified neoantigens. The Company has a license agreement with Harvard College (Harvard), granting the Company a sublicensable license to one patent family, to develop, make, use, market licensed products, and perform licensed services related to the ATLAS discovery platform.