Nanoparticle shape can improve drug delivery based on the surprising effectiveness of flexible, worm-like nanocarriers (Worms) that increase the amount of drug delivered to tumors and shrink the tumors more effectively than spherical micelles (Spheres). Here, all-atom molecular dynamics (MD) simulations are used to build a rational coarse grain (rCG) model that helps clarify shape-dependent effects in delivery of the widely used anti-cancer drug Taxol by block copolymer micelles.