Etirinotecan pegol

Etirinotecan pegol is a drug developed by Nektar Therapeutics for the treatment of certain kinds of breast cancer with brain metastases. The European Medicines Agency refused to grant it a marketing authorisation in 2017.
It works as a topoisomerase I inhibitor. Chemically, it consists of four units of irinotecan linked by carboxymethyl glycine and polyethylene glycol chains to a central pentaerythritol ether, resulting in a much longer biological half-life than that of irinotecan. It is formulated as a dihydrochloride and with 1.2 units of trifluoroacetate.