Phase II trial of thymosin fraction 5 and thymosin alpha 1

Previous Phase I trials have established the safety of administering thymosin fraction 5 and thymosin alpha 1 to patients with advanced cancer. These same trials also suggested potential immune-enhancing doses of these agents. In this study, 12 patients with colon cancer were treated with thrice weekly thymosin fraction 5 at a dose of 120 mg/m2, and 10 patients with non-small-cell lung cancer received thymosin alpha 1 at 1.2 mg/m2 thrice weekly. Five patients with hypernephroma also received one or both agents by a thrice weekly schedule. There were no tumor responses observed in any of these patients, and immune enhancement was neither obtained nor sustained. We conclude that at these doses and schedules, these hormones have very limited, if any, antitumor properties and that they are incapable of producing immune augmentation as defined by the assays used in this study.