Gritstone Oncology Inc. , National Cancer Institute (NCI) Establish a Clinical Trial Agreement to Evaluate a Neoantigen Cell Therapy-Vaccine Combination

Gritstone Oncology Inc. (GRTS), National Cancer Institute (NCI) Establish a Clinical Trial Agreement to Evaluate a Neoantigen Cell Therapy-Vaccine Combination

Gritstone bio, Inc. (Nasdaq: GRTS), a clinical-stage biotechnology company working to develop the world’s most potent vaccines, today announced that it has entered into a clinical trial agreement with the National Cancer Institute (NCI), an institute of the National Institutes of Health, to evaluate an autologous T cell therapy expressing a T cell receptor targeting mutated KRAS in combination with Gritstone’s KRAS-directed vaccine candidate, SLATE-KRAS, in a Phase 1 study. The study will be led by Steven A. Rosenberg, M.D., Ph.D., Chief of the Surgery Branch at the NCI’s Center for Cancer Research.

“We are privileged to establish this collaboration with NCI and Dr. Rosenberg, a pioneer of cancer immunotherapy and an expert in cell therapy,” said Andrew Allen, M.D., Ph.D, Co-founder, President & Chief Executive Officer of Gritstone bio. “To date, cell therapy’s success in treating blood cancers has not translated to the more common solid tumors. There is a mechanistic synergy in having cell therapy and cancer vaccines in combination. We are thrilled to test this hypothesis in patients in collaboration with a leader in the cell therapy field. We look forward to collaborating with Dr. Rosenberg and his team to generate proof-of-concept data from this promising study.”

Under the terms of the agreement, NCI will identify patients with metastatic cancer that are eligible for adoptive cell transfer based on the presence of a G12V or G12D KRAS mutation (KRASmut). Gritstone will provide the SLATE-KRAS vaccine as requested by NCI for the trial.

“The use of neoantigen vaccines to enhance the potency of neoantigen-directed T cell therapy is an attractive concept with supportive pre-clinical data,” said Karin Jooss, Executive Vice President & Head of R&D at Gritstone bio. “Our KRAS-directed vaccine has demonstrated the ability to induce and expand KRASmut-specific T cells and drive them into solid tumors in multiple clinical studies. Combining this modality with autologous KRASmut-specific TCR transduced T cells (TCR-T), as delivered by Dr Rosenberg in his clinical program at the NCI, is a rational approach to augmenting therapeutic efficacy. As a leader in the development of cancer neoantigen vaccines, we believe this approach to potentially deepening and extending the therapeutic effect of TCR-T could provide improved outcomes to solid tumor patients.”

An “off the shelf” neoantigen vaccine candidate, SLATE-KRAS demonstrated early evidence of efficacy as defined by molecular response in immune checkpoint blockade (ICB)-resistant/refractory subjects in the Phase 2 portion of an ongoing Phase 1/2 study (NCT03953235). Based on the results to date from the Phase 1/2 study, Gritstone has elected to initiate a separate, randomized Phase 2 study evaluating SLATE against a KRASmut-driven tumor type. Gritstone expects to initiate this separate, randomized study in the second half of 2023.