Extended Data Fig. 3: Robust direct ex vivo mKRAS-specific T cell responses induced by ELI-002 2P in a majority of patients.
Patients were immunized with 1.4 mg Amph-Peptides 2P admixed with 0.1, 0.5, 2.5, 5 or 10 mg of Amph-CpG-7909. PBMCs were collected for T cell response assessment at baseline and post-immunization timepoints. a, PBMCs were stimulated with OLPs to all 7 mKRAS antigens in the IFNγ/GrB Fluorospot assay for 44 hours. Shown are background-subtracted IFNγ and/or GrB SFCs per 1 × 106 PBMCs for the maximum response for each patient. T cell responders are defined as a patients having ≥2-fold increase from baseline at any post-vaccination timepoint and >50 SFC/1×106 PBMCs (dotted line). b, PBMCs were stimulated with all 7 mKRAS OLPs prior to analysis for intracellular cytokines, IFNγ, TNFa and IL-2 by flow cytometry. Shown are frequencies of the maximum cytokine producing CD4+ or CD8+ T cells for each patient. T cell responders are defined as a patients having ≥2-fold increase from baseline at any post-vaccination timepoint and > 0.1% cytokine+ (dotted line). c, Pie chart shows the percentage of T cell responders that induce T cell responses to non-immunizing antigens (G12V, G12C, G12A, G12S, G13D). d, Pie chart depicts the percentage of T cell responders exhibiting pre-existing mKRAS-specific T cells seen at baseline before ELI-002 2P vaccination, n = 21. e, PBMCs were stimulated with OLPs to all 7 mKRAS antigens in the IFNγ/GrB Fluorospot assay for 44 hours. Shown are background-subtracted IFNγ and/or GrB SFCs per 1 × 106 PBMCs for the 7 patients with post-booster vaccination timepoints. The arrows on the graph indicate the prime and boost vaccinations; dotted line indicates 50 SFC/1 x 106 PBMCs.
