Conjugates between water-soluble polymers and anticancer drugs accumulate efficiently in solid tumors, and have become effective weapons in the fight against certain cancers. In this issue, Kopecek and coworkers have designed a new generation of polymer-based therapeutics by devising a strategy to incorporate fragments of tumor-targeting monoclonal antibodies. The authors show that the antibody fragments enhance the specificity and pharmacological potency of their polymeric drug delivery system (see p. 1101).