Nanoparticles that are made by self-assembly into non-spherical shapes are promising as drug delivery vehicles. This review focuses on flexible and fragmentable filamentous micelles referred to as filomicelles made of degradable block copolymer amphiphiles. They are inspired by filoviruses and also by tubular proplatelets that break up into smaller platelets in blood flow. The synthesis and assembly of the constituent block copolymers are described together with ligand targeting and fragmentation as well as drug release in therapeutic applications to model tumors and most recently brain tumors.