Conventional ADC use covalent linkers for directly coupling of a cytotoxic drug to the antibody. This procedure is limited to a few drug molecules due to interference with the antibody binding interface or a reduction of the antibodies stability. Cellophil® offers the opportunity to reach higher payloads by coupling multiple cytotoxic drug molecules to a single Cellophil® backbone. The so charged polymer is subsequently coupled to the antibody using a novel linker structure. This ensures a preservation of the antibodies ability to target tumor cells. With higher payloads less “potential” cytotoxic drugs may be used to reach the same therapeutic effect. This would reduce the often severe side effects in conventional ADC therapies caused by unintended release of cytotoxic drugs (the so called leakiness). Further the highly hydrophilic Cellophil® polymer increases the water solubility of strong hydrophobic cytotoxic drugs which would normally suffer from low bioavailability.