Researchers identified 10 specific peptides (5 per cancer type) associated with significantly longer survival in prostate and bladder cancer patients receiving personalized peptide vaccines.
10 peptides identifiedFive peptides per cancer type were linked to significantly longer survival (HR <1.0, p<0.05) in urological cancer patients receiving personalized vaccination
What the researchers found
By analyzing survival data from 265 urological cancer patients treated with personalized peptide vaccination (PPV), researchers identified specific peptides associated with significantly longer survival. In castration-resistant prostate cancer (CRPC), five peptides (SART3-109, PTHrP-102, HNPRL-140, SART3-302, and Lck-90) were linked to improved survival. In advanced urothelial cancer (UC), five different peptides (EGF-R-800, Lck-486, PSMA-624, CypB-129, and SART3-734) showed survival benefit.
All tumor-associated antigens coding for these candidate peptides were confirmed to be expressed in actual tumor tissues by immunohistochemistry, validating that the vaccines target proteins present on the cancers.
Why it matters
Peptide cancer vaccines have shown strong immune responses but disappointing clinical results. This study suggests the problem may be peptide selection — by identifying which specific peptides correlate with longer survival, researchers can optimize personalized vaccination to include the most effective peptides for each cancer type, potentially improving outcomes.
The numbers in context
n=265 · 154 CRPC + 111 UC patients · 5 clinical trials · 5 survival-correlated peptides per cancer type · Hazard ratio <1.0 with p<0.05 for each · Tumor antigen expression confirmed in 24 tissue samples
How the study worked
Retrospective survival analysis of 265 urological cancer patients from 5 clinical trials of personalized peptide vaccination. Patients received different peptide combinations based on their HLA type and pre-existing immunity. The Cox proportional hazards model evaluated which individual peptides were associated with overall survival. Tumor antigen expression was verified by immunohistochemistry in 10 prostate cancer tissues, 4 metastatic lymph nodes, and 10 urothelial cancer tissues.
Who was studied
265 urological cancer patients (154 castration-resistant prostate cancer, 111 advanced urothelial cancer) treated with personalized peptide vaccination
What this study cannot tell us
This is a retrospective analysis of pooled trial data, not a prospective randomized study testing specific peptide combinations. Multiple comparisons increase the risk of false positives. The personalized nature of PPV means each patient received different peptides, making direct comparisons difficult. Sample sizes per peptide subgroup are likely small. The survival associations are correlative, not causal.
How to read the evidence
This is a retrospective analysis of pooled data from 5 clinical trials. While the sample size (265 patients) is reasonable and statistical methods are appropriate, the retrospective design, multiple comparisons, and personalized treatment approach limit the strength of causal conclusions.
When this study was published
Published in 2018, this study reflects a period of active clinical exploration of personalized peptide vaccines in urology. The field has continued to evolve toward neoantigen-based approaches, but the peptide selection methodology remains relevant.
The bigger picture
Personalized cancer vaccination is one of the most promising frontiers in oncology, with approaches ranging from peptide vaccines to mRNA vaccines. This study addresses a fundamental challenge: which peptides should be included in the vaccine? By linking specific peptides to actual survival outcomes, it moves beyond immune response as a surrogate endpoint and toward clinically meaningful selection criteria. The approach of mining existing trial data to optimize peptide selection could accelerate the development of more effective cancer vaccines.
Questions still open
- Would a prospective trial using only the survival-correlated peptides show improved outcomes compared to the broader peptide pools used in the original trials?
- Do the survival-associated peptides work by directly killing tumor cells, or by activating broader immune surveillance?
- Can this survival-based peptide selection approach be applied to other cancer types beyond prostate and bladder cancer?
Common questions
What is personalized peptide vaccination for cancer?
Why haven't peptide cancer vaccines worked well despite generating immune responses?
Read the original research
Survival analysis of multiple peptide vaccination for the selection of correlated peptides in urological cancers.
Cancer science, 109(9), 2660-2669
Citation
Noguchi, Masanori; Koga, Noriko; Moriya, Fukuko; Suekane, Shigetaka; Yutani, Shigeru; Yamada, Akira; Shichijo, Shigeki; Kakuma, Tatuyuki; Itoh, Kyogo. (2018). Survival analysis of multiple peptide vaccination for the selection of correlated peptides in urological cancers.. Cancer science, 109(9), 2660-2669. https://doi.org/10.1111/cas.13709