NuCana plc announced interim data from the ongoing NuTide:302 study at the ASCO GI Conference, being held virtually January 15-17, 2021. NuTide:302 is a three-part study investigating NUC-3373, NuCana’s targeted thymidylate synthase inhibitor, in heavily pre-treated patients with metastatic colorectal cancer. The study is evaluating NUC-3373’s optimal dose and schedule in combination with agents commonly used to treat patients with colorectal cancer and is assessing safety, pharmacokinetics and anti-cancer activity. NUC-3373 has been designed to overcome the main challenges associated with 5-FU and capecitabine, including cancer-resistance mechanisms which limit efficacy, off-target toxicity and administration burdens. The ASCO GI presentation highlighted data from 37 patients treated in Part I of the study who received NUC-3373 either as monotherapy or in combination with leucovorin. Ten patient case studies highlighted NUC-3373’s ability to stabilize disease and achieve prolonged durations of progression-free survival. Many patients achieved longer progression-free survival on NUC-3373 than they had on their prior line of therapy and five patients experienced tumor shrinkage. These patients included: A fourth-line patient who achieved a Partial Response with a 40% reduction in tumor volume; A third-line patient who achieved a 28% reduction in tumor volume after their disease rapidly progressed through all prior fluoropyrimidine-containing regimens.