TY - JOUR
T1 - A Phase 2, Double-blind, Randomized Controlled Trial of PROSTVAC in Prostate Cancer Patients on Active Surveillance
AU - Parsons, J. Kellogg
AU - Pinto, Peter A.
AU - Pavlovich, Christian P.
AU - Uchio, Edward
AU - Nguyen, Mike N.
AU - Kim, Hyung L.
AU - Gulley, James L.
AU - Sater, Houssein Abdul
AU - Jamieson, Christina
AU - Hsu, Chiu Hsieh
AU - Wojtowicz, Malgorzata
AU - House, Margaret
AU - Schlom, Jeffrey
AU - Donahue, Renee N.
AU - Dahut, William L.
AU - Madan, Ravi A.
AU - Bailey, Shania
AU - Centuori, Sara
AU - Bauman, Julie E.
AU - Parnes, Howard L.
AU - Chow, H. H.Sherry
N1 - Publisher Copyright: © 2022 European Association of Urology
PY - 2023/5
Y1 - 2023/5
N2 - Background: There is an unmet clinical need for interventions to prevent disease progression in patients with localized prostate cancer on active surveillance (AS). Objective: To determine the immunologic response to the PROSTVAC vaccine and the clinical indicators of disease progression in patients with localized prostate cancer on AS. Design, setting, and participants: This was a phase 2, double-blind, randomized controlled trial in 154 men with low- or intermediate-risk prostate cancer on AS. Intervention: Participants were randomized (2:1) to receive seven doses of subcutaneous PROSTVAC, a vaccinia/fowlpox viral vector–based immunotherapy containing a prostate-specific antigen (PSA) transgene and three T-cell co-stimulatory molecules, or an empty fowlpox vector (EV) over 140 d. Outcome measurements and statistical analysis: The primary outcome was the change from baseline in CD4 and CD8 T-cell infiltration in biopsy tumor tissue. Key secondary outcomes were safety and changes in prostate biopsy tumor pathology, peripheral antigen-specific T cells, and serum PSA. Continuous variables were compared using nonparametric tests. Categorical variables were compared using Fisher's exact test. Results and limitations: The PROSTVAC/EV vaccination was well tolerated. All except one participant completed the vaccination series. Changes in CD4 or CD8 density in biopsy tumor tissue did not differ between the PROSTVAC and EV arms. The proportions of patients with Gleason upgrading to grade group 3 after treatment was similar between the arms. There were no differences in postvaccination peripheral T-cell responses or the PSA change from baseline to 6-mo post-treatment follow-up between the groups. Conclusions: In this first-of-kind trial of immunotherapy in patients on AS for prostate cancer, PROSTVAC did not elicit more favorable prostate tissue or peripheral T-cell responses than the EV. There was no difference between the arms in clinicopathologic effects. Despite the null findings, this is the first study reporting the feasibility and acceptability of an immunotherapy intervention in the AS setting. Patient summary: We looked at responses after an experimental prostate cancer vaccine in patients with prostate cancer on active surveillance (AS). Participants who received the vaccine did not show more favorable outcomes than those receiving the control. Despite these findings, this is the first report showing the feasibility and acceptability of immunotherapy for prostate cancer in patients on AS.
AB - Background: There is an unmet clinical need for interventions to prevent disease progression in patients with localized prostate cancer on active surveillance (AS). Objective: To determine the immunologic response to the PROSTVAC vaccine and the clinical indicators of disease progression in patients with localized prostate cancer on AS. Design, setting, and participants: This was a phase 2, double-blind, randomized controlled trial in 154 men with low- or intermediate-risk prostate cancer on AS. Intervention: Participants were randomized (2:1) to receive seven doses of subcutaneous PROSTVAC, a vaccinia/fowlpox viral vector–based immunotherapy containing a prostate-specific antigen (PSA) transgene and three T-cell co-stimulatory molecules, or an empty fowlpox vector (EV) over 140 d. Outcome measurements and statistical analysis: The primary outcome was the change from baseline in CD4 and CD8 T-cell infiltration in biopsy tumor tissue. Key secondary outcomes were safety and changes in prostate biopsy tumor pathology, peripheral antigen-specific T cells, and serum PSA. Continuous variables were compared using nonparametric tests. Categorical variables were compared using Fisher's exact test. Results and limitations: The PROSTVAC/EV vaccination was well tolerated. All except one participant completed the vaccination series. Changes in CD4 or CD8 density in biopsy tumor tissue did not differ between the PROSTVAC and EV arms. The proportions of patients with Gleason upgrading to grade group 3 after treatment was similar between the arms. There were no differences in postvaccination peripheral T-cell responses or the PSA change from baseline to 6-mo post-treatment follow-up between the groups. Conclusions: In this first-of-kind trial of immunotherapy in patients on AS for prostate cancer, PROSTVAC did not elicit more favorable prostate tissue or peripheral T-cell responses than the EV. There was no difference between the arms in clinicopathologic effects. Despite the null findings, this is the first study reporting the feasibility and acceptability of an immunotherapy intervention in the AS setting. Patient summary: We looked at responses after an experimental prostate cancer vaccine in patients with prostate cancer on active surveillance (AS). Participants who received the vaccine did not show more favorable outcomes than those receiving the control. Despite these findings, this is the first report showing the feasibility and acceptability of immunotherapy for prostate cancer in patients on AS.
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U2 - 10.1016/j.euf.2022.12.002
DO - 10.1016/j.euf.2022.12.002
M3 - Article
C2 - 36517408
SN - 2405-4569
VL - 9
SP - 447
EP - 454
JO - European Urology Focus
JF - European Urology Focus
IS - 3
ER -