eFFECTOR Therapeutics, Inc. announced a clinical collaboration with Jennifer Caswell-Jin, M.D., Assistant Professor of Medicine at Stanford Medicine, who will serve as principal investigator in an investigator-initiated trial evaluating zotatifin in patients with estrogen receptor-positive (ER+), human epidermal growth factor receptor 2-negative (HER2) breast cancer in a pre-operative setting. This trial will bring to the clinic the science of integrative subgroups of breast cancer, building on work done by Christina Curtis, Ph.D., Professor of Medicine, Genetics, and Biomedical Data Science, and Director of Artificial Intelligence and Cancer Genomics at Stanford Medicine. The primary objective of the study is to assess change in tumor proliferative status, as measured by Ki67 staining, from baseline to 14 days after preoperative treatment with either regimen.