Long-term first-in-man Phase I/II study of an adjuvant dendritic cell vaccine in patients with high-risk prostate cancer after radical prostatectomy

Prostate. 2022 Feb;82(2):245-253. doi: 10.1002/pros.24267. Epub 2021 Nov 11.

Abstract

Background: Patients with high-risk prostate cancer (PC) can experience biochemical relapse (BCR), despite surgery, and develop noncurative disease. The present study aimed to reduce the risk of BCR with a personalized dendritic cell (DC) vaccine, given as adjuvant therapy, after robot-assisted laparoscopic prostatectomy (RALP).

Methods: Twelve weeks after RALP, 20 patients with high-risk PC and undetectable PSA received DC vaccinations for 3 years or until BCR. The primary endpoint was the time to BCR. The immune response was assessed 7 weeks after surgery (baseline) and at one-time point during the vaccination period.

Results: Among 20 patients, 11 were BCR-free over a median of 96 months (range: 84-99). The median time from the end of vaccinations to the last follow-up was 57 months (range: 45-60). Nine patients developed BCR, either during (n = 4) or after (n = 5) the vaccination period. Among five patients diagnosed with intraductal carcinoma, three experienced early BCR during the vaccination period. All patients that developed BCR remained in stable disease within a median of 99 months (range: 74-99). The baseline immune response was significantly associated with the immune response during the vaccination period (p = 0.015). For patients diagnosed with extraprostatic extension (EPE), time to BCR was longer in vaccine responders than in non-responders (p = 0.09). Among 12 patients with the International Society of Urological Pathology (ISUP) grade 5 PC, five achieved remission after 84 months, and all mounted immune responses.

Conclusion: Patients diagnosed with EPE and ISUP grade 5 PC were at particularly high risk of developing postsurgical BCR. In this subgroup, the vaccine response was related to a reduced BCR incidence. The vaccine was safe, without side effects. This adjuvant first-in-man Phase I/II DC vaccine study showed promising results. DC vaccines after curative surgery should be investigated further in a larger cohort of patients with high-risk PC.

Keywords: dendritic cells; prostate cancer; radical prostatectomy; vaccine.

Publication types

  • Clinical Trial, Phase I
  • Clinical Trial, Phase II
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Biomarkers / blood
  • Cancer Vaccines / administration & dosage*
  • Dendritic Cells / immunology
  • Humans
  • Male
  • Middle Aged
  • Neoplasm Metastasis / prevention & control*
  • Outcome Assessment, Health Care / methods
  • Outcome Assessment, Health Care / statistics & numerical data
  • Prostate* / immunology
  • Prostate* / pathology
  • Prostate-Specific Antigen / blood
  • Prostatectomy / adverse effects*
  • Prostatectomy / methods
  • Prostatic Neoplasms* / blood
  • Prostatic Neoplasms* / mortality
  • Prostatic Neoplasms* / pathology
  • Prostatic Neoplasms* / surgery
  • Secondary Prevention / methods*
  • Survival Analysis
  • Time
  • Vaccines, Synthetic / administration & dosage

Substances

  • Biomarkers
  • Cancer Vaccines
  • UV1 vaccine
  • Vaccines, Synthetic
  • Prostate-Specific Antigen