Genomic Biomarkers Predict Response to Combined ATR Inhibition and Radiotherapy.

For decades, chemoradiosensitization with checkpoint kinase inhibitors has been proposed but largely unexplored. A recent study reports that the novel ataxia telangiectasia and Rad3-related kinase inhibitor RP-3500 synergizes with radiation to control Atm-/- tumors in vivo. RP-3500 did not radiosensitize wild-type or Brca-1-deficient tumors, highlighting the need for a genotype-tailored approach. See related article by Ng et al., p. 5643.