Long-Acting Formulation of Irinotecan for Breast Cancer

Developing effective treatments for refractory metastatic breast cancer remains a major challenge, particularly for triple-negative breast cancer. Developing drugs that have novel targets or mechanisms of action are urgently needed. Although the topoisomerase-1 inhibitor irinotecan has limited activity and use as a treatment for breast cancer, etirinotecan pegol, a long-acting formulation with unique pharmacokinetics and distribution, might be more effective. Specifically, etirinotecan pegol has a large polyethylene glycol core to which four molecules of irinotecan are linked; and, because of its large size, etirinotecan pegol does not easily cross normal vasculature, but it more readily penetrates leaky tumor vasculature where the irinotec…