In June 2023 at the European Haematology Association event Mendus presented new clinical data from the Phase II ADVANCE II trial in acute myeloid leukaemia (AML) maintenance. The data show that treatment with vididencel led to increased levels of activated, cancer-killing T cells and reduced levels of immunosuppressive T cells in most patients.
Vididencel is an allogenic, leukaemic cell-based relapse vaccine that expresses co-stimulatory molecules, resembling activated dendritic cells and tumour associated antigens (TAA). It is delivered intradermally and generates an inflammatory response and “indirect priming of the immune system”.
The primary endpoint of the study was MRD response, or minimal residue disease, and patients with such a response had the highest levels of these tumour antigen-specific T cells. They also showed a “trend” towards higher levels of “circulating antigen-presenting cells (APCs) and B cells” after treatment with vididencel.
Dr Jeroen Rovers, Chief Medical Officer at Mendus, commented that “immunomonitoring is an important part” of the trial, providing “in-depth analysis of the interaction between vididencel and the immune system”.
“The results…demonstrate a clear correlation between the patients’ immune status and immune responses observed following vididencel administration and these previously reported survival outcomes.”
Following these results, Dr Rovers considers “priming the immune system to eradicate or control residual disease” an “effective strategy in AML”.
“The ADVANCE II trial continues to evaluate patients in long-term follow-up with updated survival results expected for Q4 2023.”
A closer look at the data
At the time of data collection 20 evaluable AML patients had been analysed. Functional T cell analysis revealed vaccine induced responses (VIRs) to antigens in vididencel in 17 out of 20 patients. The highest number of VIRs occurred in MRD responders, which indicates a “positive correlation of VIRs with clinical outcomes”.