ClinicalTrials.gov posted results on 28 August 2026 for a completed Phase 2 trial of pembrolizumab in patients with neuroendocrine tumors and liver metastases. Among the reported groups, the overall response proportion was 0.35 with pembrolizumab and 177Lu DOTATATE, compared with 0 in the pembrolizumab-plus-TAE and pembrolizumab-plus-Yttrium-90 microsphere radioembolization groups.
Background
The study evaluated pembrolizumab with liver-directed therapy or peptide receptor radionuclide therapy in patients with well-differentiated neuroendocrine tumors that had spread to the liver. The registered conditions were metastatic malignant neoplasm in the liver and neuroendocrine neoplasm. The interventions included pembrolizumab and peptide receptor radionuclide therapy using 177Lu-DOTATATE, as well as transarterial embolization and Yttrium-90 microsphere radioembolization.
The trial record’s summary describes pembrolizumab as an immunotherapy with a monoclonal antibody that may help the immune system attack cancer and may interfere with tumor growth and spread. Liver-directed therapies were used as treatment partners in the study.
Trial design
This was a completed, pilot Phase 2 trial that enrolled 32 participants with neuroendocrine tumors and symptomatic and/or progressive liver metastases. The reported treatment groups were Group I, pembrolizumab with 177Lu DOTATATE; Group II, pembrolizumab with transarterial embolization; and Group III, pembrolizumab with Yttrium-90 microsphere radioembolization.
The listed outcome was the proportion of participants with an overall response. The supplied record did not include primary outcome entries, statistical analyses, p-values, or confidence-interval values.
Key results
Group I, which received pembrolizumab and 177Lu DOTATATE, had an overall response proportion of 0.35. The corresponding proportion was 0 for Group II, pembrolizumab with TAE, and 0 for Group III, pembrolizumab with Yttrium-90 microsphere radioembolization. Confidence-interval fields were listed for these measurements, but no interval values were supplied.
For treatment-related adverse events by maximum grade in Group I, the record listed participant counts of 3, 1, 1, 2, 1, 2, 2, 1, and 1. The supplied data did not identify which count corresponded to each maximum grade.
What this means
The posted results show a reported overall response proportion in the pembrolizumab-plus-177Lu-DOTATATE group, while the two other listed combinations had reported proportions of zero. Because the available data do not provide group sizes, confidence-interval values, statistical tests, or grade labels for adverse events, they do not establish a comparative efficacy or safety conclusion among the treatment groups.
The record describes a completed pilot study rather than an approval or label change. The results apply to the studied population of patients with neuroendocrine tumors and liver metastases and do not, on the supplied evidence alone, indicate a new pembrolizumab indication.
Source
Source: ClinicalTrials.gov, registry record for “Pembrolizumab With Liver-Directed or Peptide Receptor Radionuclide Therapy for Neuroendocrine Tumors and Liver Metastases,” results posted 28 August 2026. The record is available at clinicaltrials.gov/study/NCT03457948.