19-Peptide Cancer Vaccine Shows Promise in Refractory Triple-Negative Breast Cancer | Research

The takeaway

A mixed 19-peptide cancer vaccine produced peptide-specific immune responses correlating with survival in refractory triple-negative breast cancer patients, with a median survival of 24.4 months in completers.

24.4 months
Median overall survival in the 10 refractory mTNBC patients who completed the 19-peptide vaccination schedule

What the researchers found

Peptide-specific IgG responses correlated with overall survival (P < .01), and median OS was 24.4 months in the 10 patients who completed vaccination — notable for refractory mTNBC.

Why it matters

Triple-negative breast cancer has the worst prognosis and fewest treatment options. A 24.4-month median survival in refractory patients is remarkable for this population.

The numbers in context

n=14; 19 peptides; weekly x 6 weeks; mOS 11.5 mo (all) / 24.4 mo (10 completers); IgG-OS correlation p<0.01; no severe AEs

How the study worked

Phase II single-arm clinical trial, 14 patients, weekly vaccination for 6 weeks, immune response monitoring via peptide-specific IgG, survival analysis.

Who was studied

14 patients with advanced metastatic TNBC refractory to chemotherapy

What this study cannot tell us

Very small single-arm trial (14 patients) without a control group. Selection bias in the completer analysis. Early phase data.

How to read the evidence

Early phase II single-arm trial with very small sample (14 patients). Promising survival data but requires randomized confirmation.

When this study was published

Published in 2020. Peptide-based cancer vaccines for TNBC continue to be developed.

The bigger picture

This trial provides early evidence that multi-peptide cancer vaccines can produce meaningful immune responses and survival benefits even in heavily pretreated TNBC patients.

Questions still open

Would a randomized controlled trial confirm the survival benefit?
Can biomarkers like CRP identify patients most likely to benefit?
Could this vaccine be combined with checkpoint inhibitors for enhanced efficacy?

Common questions

What is a peptide cancer vaccine?

A mixture of small protein fragments (peptides) from tumor-associated proteins is injected to train the immune system to recognize and attack cancer cells. This vaccine used 19 different peptides to broaden the immune response.

What is triple-negative breast cancer and why is it hard to treat?

TNBC lacks the three receptors (estrogen, progesterone, HER2) that most breast cancer drugs target. This makes it resistant to hormonal and HER2-targeted therapies, leaving chemotherapy as the main option. When chemo fails, treatment options are extremely limited.

Read the original research

Early phase II study of mixed 19-peptide vaccine monotherapy for refractory triple-negative breast cancer.

Cancer science, 111(8), 2760-2769

View on PubMed ↗Publisher’s paper ↗

Citation

Toh, Uhi; Sakurai, Sayaka; Saku, Shuko; Takao, Yuko; Okabe, Mina; Iwakuma, Nobutaka; Shichijo, Shigeki; Yamada, Akira; Itoh, Kyogo; Akagi, Yoshito. (2020). Early phase II study of mixed 19-peptide vaccine monotherapy for refractory triple-negative breast cancer.. Cancer science, 111(8), 2760-2769. https://doi.org/10.1111/cas.14510