The purpose of this study is to evaluate the dose, safety, immunogenicity and early
clinical activity of GRT-C903 and GRT-R904, a neoantigen-based therapeutic cancer
vaccine, in combination with immune checkpoint blockade, in patients with advanced or
metastatic non-small cell lung cancer, microsatellite stable colorectal cancer,
pancreatic cancer, and shared neoantigen-positive tumors. Based on the Phase 1 data, an
updated vaccine candidate (SLATE-KRAS or version 2) was developed that removed 16 of the
20 mutations included in the original vaccine (version 1) and solely targets KRAS
mutations.
Study sponsor and potential other locations can be found on ClinicalTrials.gov for NCT03953235.
Tumors harboring non-synonymous deoxyribonucleic acid (DNA) mutations can present
peptides containing these mutations as non-self antigens in the context of HLA on the
tumor cell surface. A fraction of mutated peptides result in neoantigens capable of
generating T-cell responses that exclusively target tumor cells. Some of these
tumor-specific neoantigens are known or expected to be common across a subset of patients
and are called shared neoantigens. This study aims to target shared neoantigens using a
heterologous prime/boost therapeutic vaccine approach (GRT-C903 first followed by
GRT-R904) in combination with checkpoint blockade to stimulate an immune response. This
study will explore the safety and early clinical activity of this neoantigen-based
immunotherapy intended to induce T-cell responses specific for the shared neoantigens
contained within the therapeutic vaccine. Phase 1 will test multiple doses and
combinations with checkpoint blockade and Phase 2 will test for early signs of clinical
activity using a vaccine regimen based on Phase 1 data.
Lead OrganizationGritstone bio, Inc.