The invention relates to a composite system comprising at least one biodegradable blend, containing at least one biodegradable block copolyester urethane (PEU) and also at least one polyhydroxyalkanoate (PHA), possibly a filler comprising a polysaccharide and/or derivatives thereof and also possibly further biocompatible additives. Composite systems of this type are used for producing molded articles, molded parts or extrudates. Furthermore, the invention relates to possibilities for using the composite system.