Using nanomedicine to treat cancer just got a step closer to the clinic, according to interim results from a phase 1 trial of targeted nanoparticle-mediated docetaxel (DTXL) delivery to treat various solid tumors. Hrkach et al. restricted nanoparticle components to already clinically approved materials to expedite the translation of the nanoparticle from mouse to man. A library of 100 nanoparticle variants was generated by combining varying proportions of the key components of the nanoparticle, namely polymers that form a core, the anticancer drug DTXL encapsulated inside the core and a surface ligand that binds prostate-specific membrane antigen, which is present in nearly all solid tumors. Comparing pharmacokinetics of nanoparticle-library variants in rats enabled identification of the best-performing DTXL-NP. Importantly, the authors found that the plasma concentrations of DTXL delivered by this nanoparticle were three orders of magnitude higher than those of commercial DTXL (Taxotere) injected intravenously in different preclinical animal models, suggesting that drug doses can be reduced through nanoparticle delivery. In an ongoing phase 1 trial, patients with various solid tumors were dosed every 3 weeks with increasing amounts of DTXL-NP. The pharmacokinetics of DTXL-NP in humans mirrored those obtained in preclinical studies, and tumors (lung and tonsillar cancer) shrank in 2 of 17 patients. (Sci. Transl. Med. 4, 128ra39, 2012)