In a Dutch single-center phase I/II study reported in the Journal of Clinical Oncology, van ‘t Land et al found that adjuvant autologous dendritic cell vaccination was associated with promising recurrence-free survival in patients who had undergone resection and standard-of-care treatments for pancreatic cancer.
As noted by the investigators, “Immunotherapies have shown limited responses in patients with advanced pancreatic cancer. Recently, we reported that dendritic cell–based immunotherapy induced T-cell responses against pancreatic cancer antigens. The primary objective of [the current] study was to determine the efficacy of dendritic cell–based immunotherapy to prevent recurrence of disease.”
Study Details
Thirty-eight evaluable patients were enrolled into the study at Erasmus MC Cancer Institute between February 2019 and November 2022. Dendritic cell vaccinations consisted of autologous dendritic cells pulsed with an allogeneic mesothelioma tumor cell lysate consisting of antigens also expressed in pancreatic ductal adenocarcinoma. Patients received three biweekly vaccinations with approximately 25 x 106 dendritic cells per vaccination, with fourth and fifth vaccinations given at 3 and 6 months after the third vaccination in the absence of cancer recurrence. The primary outcome measure was 2-year recurrence-free survival, with a rate of ≥ 60% defined as a clinically meaningful improvement vs historical controls.
Key Findings
Overall, 28 patients (74%) received five dendritic cell vaccinations, 3 (8%) received four, and 7 (16%) received three.
After a median follow-up of 25.5 months, 26 patients (68%) had not developed recurrence, resulting in a 2-year recurrence-free survival of 64%. Overall survival at 2 years was 83%.
Vaccination was associated with enrichment of circulating activated CD4+T cells, with treatment-induced immune responses detected in vitro. T-cell receptor sequencing in a resected solitary lung metastasis showed an influx of vaccine-specific T cells.
All patients were discharged after every vaccination without symptoms or changes in vital signs. Treatment-related adverse events consisted of grade 1 events in 97% of patients, grade 2 events in 18%, and a grade 3 event in one patient (3%; dyspnea).
The investigators concluded, “This study reached its primary endpoint of a 2-year recurrence-free survival rate of ≥ 60% following pancreatectomy after standard-of-care treatment and adjuvant dendritic cell–based immunotherapy in patients with pancreatic cancer. These results warrant a future randomized trial.”
Casper H.J. van Eijck, MD, PhD, of the Department of Surgery, Erasmus MC Cancer Institute, is the corresponding author for the Journal of Clinical Oncology article.
Disclosure: The study was supported by the Survival with Pancreatic Cancer Foundation and Health ~Holland TKI Life Sciences & Health. For full disclosures of the study authors, visit ascopubs.org.
