A phase I trial combining a multi-peptide cancer vaccine with azacitidine in five high-risk MDS patients found no immune response or clinical benefit, with all patients progressing to acute leukemia within an average of 5.2 months.
0 of 5 patients respondedDespite targeting four tumor antigens upregulated by azacitidine, no detectable immune responses were generated, and all patients progressed to acute myeloid leukemia within an average of 5.2 months.
What the researchers found
Five patients with high-risk MDS who had previously responded to azacitidine (AZA) monotherapy received a multi-peptide vaccine targeting NY-ESO-1, MAGE-A3, PRAME, and WT-1 antigens.
Results were uniformly negative: no specific immune responses were detected by intracellular cytokine staining or ELISpot assays. Only minor changes in immune cell phenotype and marker expression were observed. All five patients progressed to acute myeloid leukemia (AML) with a mean time to progression of 5.2 months (range 2.8-7.6). Mean survival was 18.1 months from MDS diagnosis (range 10.9-30.6) and 11.3 months from study enrollment (range 4.3-22.2). Bone marrow sequencing revealed clonal expansion of malignant cells and emergence of novel mutations.
Why it matters
This was the first study to test whether epigenetic therapy (which unmasks hidden cancer targets) could synergize with a multi-peptide cancer vaccine in MDS. While the results were negative, they provide critical information: high-risk MDS patients may have immune systems too compromised to mount vaccine responses, even when tumor antigens are artificially upregulated. This shapes future research by highlighting the need for immune-restoring strategies before attempting vaccination in this population.
How the study worked
This was a phase I (safety and feasibility) clinical trial. Five patients with high-risk MDS who had responded to azacitidine monotherapy were enrolled. They received AZA combined with a therapeutic peptide vaccine targeting four shared tumor-associated antigens known to be upregulated by AZA treatment. Immune responses were monitored using intracellular cytokine staining and ELISpot assays. Immune cell phenotyping tracked changes in stimulatory and inhibitory markers. Bone marrow was sequenced to track clonal evolution. The trial was terminated early due to lack of clinical benefit.
What this study cannot tell us
The major limitation is the extremely small sample size (n=5), which severely limits the ability to draw generalizable conclusions. There was no control group for comparison. All patients had high-risk MDS that may have been inherently resistant to immune-based approaches. The lack of immune response could reflect the specific peptide vaccine design, the patient population's immune status, or both. The early termination prevented assessment of whether longer treatment might have produced different results.
How to read the evidence
This is a phase I clinical trial — the earliest stage of human testing focused on safety rather than efficacy. With only 5 patients and no control group, the evidence level is low for drawing efficacy conclusions. However, the consistent lack of immune response across all patients is a meaningful negative finding that informs future trial design.
When this study was published
Published in 2022, this study reflects recent experience with peptide vaccine immunotherapy in blood cancers. The challenges of inducing immune responses in MDS patients remain an active area of research.
The bigger picture
Cancer peptide vaccines aim to train the immune system to recognize and attack tumors using short protein fragments (peptides) from cancer-specific targets. This study represents an important negative result in the field — demonstrating that even a well-designed multi-epitope vaccine combined with a synergistic drug cannot overcome the immune dysfunction present in advanced blood cancers. The findings contribute to the growing understanding that the tumor microenvironment and immune suppression must be addressed before vaccine strategies can succeed.
Questions still open
- Could immune checkpoint inhibitors or other immune-restoring agents enable vaccine responses in MDS patients if given before or alongside peptide vaccination?
- Would this peptide vaccine approach work better in lower-risk MDS patients with less immune dysfunction?
- Did the clonal evolution observed during the trial represent natural disease progression or was it influenced by the treatment?
Common questions
What is a multi-peptide cancer vaccine and how is it supposed to work?
Why didn't the vaccine work in these patients?
Read the original research
Epigenetic therapy in combination with a multi-epitope cancer vaccine targeting shared tumor antigens for high-risk myelodysplastic syndrome - a phase I clinical trial.
Cancer immunology, immunotherapy : CII, 71(2), 433-444
Citation
Holmberg-Thydén, Staffan; Dufva, Inge Høgh; Gang, Anne Ortved; Breinholt, Marie Fredslund; Schejbel, Lone; Andersen, Mette Klarskov; Kadivar, Mohammad; Svane, Inge Marie; Grønbæk, Kirsten; Hadrup, Sine Reker; El Fassi, Daniel. (2022). Epigenetic therapy in combination with a multi-epitope cancer vaccine targeting shared tumor antigens for high-risk myelodysplastic syndrome - a phase I clinical trial.. Cancer immunology, immunotherapy : CII, 71(2), 433-444. https://doi.org/10.1007/s00262-021-02993-6