Phase I Trial of Overlapping Long Peptides from a Tumor Self-Antigen and Poly-ICLC Shows Rapid Induction of Integrated Immune Response in Ovarian Cancer Patients

TLDR: The current study shows that NY-ESO-1 OLP vaccine is safe and rapidly induces consistent integrated immune responses (antibody, CD8+ and CD4+) in nearly all vaccinated patients when given with appropriate adjuvants.

Abstract: Purpose: Long peptides are efficiently presented to both CD4 + and CD8 + T cells after intracellular processing by antigen-presenting cells. To investigate the safety and in vivo immunogenicity of synthetic overlapping long peptides (OLP) from a human tumor self-antigen, we conducted a phase I clinical trial with OLP from cancer-testis antigen NY-ESO-1 in various adjuvant combinations. Experimental Design: Twenty-eight patients with advanced ovarian cancer in second or third remission were enrolled sequentially in three cohorts and received at least one vaccination. Patients in Cohort 1 ( n = 4) received 1.0 mg OLP, Cohort 2 ( n = 13) received OLP in Montanide-ISA-51, and Cohort 3 ( n = 11) received OLP + 1.4 mg Poly-ICLC in Montanide-ISA-51 on weeks 1, 4, 7, 10, and 13. Humoral and cellular responses were evaluated by standardized immunomonitoring techniques (ELISA, ELISPOT assay, intracellular cytokine staining, and tetramer staining). Results: The vaccine was generally well tolerated with injection site reactions and fatigue that resolved. NY-ESO-1–specific antibody and CD8 + T cells were undetectable after vaccination with OLP alone, but were found in 6 of 13 (46%) and 8 of 13 (62%) patients, respectively, after vaccination with OLP+Montanide, and in 10 of 11 (91%) and 10 of 11 (91%) patients, respectively, after vaccination with OLP+Montanide+Poly-ICLC. NY-ESO-1–specific CD4 + T cells were detected in all patients with greater frequency and polyclonality when Montanide-ISA-51 was used for vaccination. Inclusion of Poly-ICLC as an adjuvant further accelerated the induction of NY-ESO-1–specific immune responses. Conclusions: The current study shows that NY-ESO-1 OLP vaccine is safe and rapidly induces consistent integrated immune responses (antibody, CD8 + and CD4 + ) in nearly all vaccinated patients when given with appropriate adjuvants. Clin Cancer Res; 18(23); 6497–508. ©2012 AACR .