Results from the PHASE1/PHASE2 study NCT05714553 investigating Pembrolizumab in combination with fosifloxuridine nafalbenamide (NUC-3373) and leucovorin in patients with advanced solid tumors were posted on 2026-07-23. The trial, which was terminated, reported that 2 participants in the pembrolizumab combination arm achieved an objective response rate (ORR).

Background

This study investigated NUC-3373 in combination with pembrolizumab and leucovorin, or docetaxel and leucovorin, for the treatment of patients with advanced solid tumors, including melanoma.

Trial design

The PHASE1/PHASE2 study, identified as NCT05714553, was an open-label, multi-arm, parallel cohort, dose validation and expansion design. The study enrolled 19 participants with conditions including Advanced Cancer, Advanced Solid Tumor, Neoplasm Malignant, Metastatic Cancer, and Melanoma. The trial was terminated. It evaluated the safety, efficacy, and pharmacokinetics of NUC-3373 in combination with other agents, specifically in two modules: Module 1 (NUC-3373 + leucovorin + pembrolizumab) and Module 2 (NUC-3373 + leucovorin + docetaxel).

Key results

Key efficacy and safety outcomes included:

  • For Number of Participants With DLTs in Each Module, 0 participants were reported in Module 1 (NUC-3373 + LV + Pembrolizumab) and 0 participants in Module 2 (NUC-3373 + LV + Docetaxel).
  • For Number of Patients Achieving a Reduction in Tumour Volume (Objective Response Rate; ORR), 2 participants were reported in Module 1 (NUC-3373 + LV + Pembrolizumab), while 0 participants were reported in Module 2 (NUC-3373 + LV + Docetaxel).
  • For Number of Patients Achieving a Reduction or Stabilisation in Tumor Volume (Disease Control Rate; DCR), 6 participants were reported in Module 1 (NUC-3373 + LV + Pembrolizumab), and 2 participants were reported in Module 2 (NUC-3373 + LV + Docetaxel).

What this means

The results from the PHASE1/PHASE2 study NCT05714553 indicate that the combination of NUC-3373, leucovorin, and pembrolizumab showed early signs of objective response and disease control in a small cohort of participants with advanced solid tumors. Specifically, 2 participants achieved an objective response and 6 participants achieved disease control in this arm. In comparison, the combination with docetaxel showed 0 participants with objective response and 2 participants with disease control. Both modules reported 0 participants with dose-limiting toxicities (DLTs). The trial was terminated, which may impact further investigation of these specific combinations.

Source

This information was sourced from ClinicalTrials.gov, documenting the results of trial NCT05714553, which were posted on 2026-07-23. The study details are available on clinicaltrials.gov.