The early results are part of a phase II trial with 31 subjects to be enrolled in its chronic myelogenous leukaemia (CML) arm. It is the first research study to combine DNA vaccination with electroporation delivery of WT1 antigens, targeting the stimulation of high and durable levels of immune responses. The findings could lead to the development of better clinical outcomes for leukaemia.
The researchers also identified T cell immune responses, such as killer T cells, saying that antibody and T cell responses are strong signals of the DNA vaccine's potential to treat the disorder.
So far, 14 CML patients are taking part in the study, and 13 unvaccinated CML patients are part of the control group. The researchers showed that the vaccine is safe overall and well tolerated by the patients participating in the study.
The team plans to evaluate T cell immune responses and assess the effect the vaccination has on the molecular marker BCR-ABL, which is a specific chromosomal abnormality linked with CML disease.
Thanks to the early positive results obtained with the vaccinated group, the researchers will enrol the acute myeloid leukaemia (AML) clinical trial arm with a total target of 37 subjects in both the vaccinated and control groups.
'These preliminary data show strong vaccine-induced immune responses in vaccinated subjects in the CML arm,' said Professor Christian Ottensmeier of the University of Southampton and the lead investigator of this study. 'We are looking forward to enrolling and testing the vaccine's impact in AML patients, who currently have limited treatment options and a low rate of progression free survival.'
The open-label, multi-centre phase II clinical trial is analysing a DNA vaccine-based immune therapy to treat the two types of leukaemia. The DNA vaccine is delivered using Inovio Pharmaceuticals Inc. proprietary electroporation technology.
Latest data show that leukaemia is responsible for 222,000 deaths worldwide and 300,000 new cases are reported each year. Experts identified a strong link between WT1 and these types of cancer.
Professor Ottensmeier presented the study's initial results at the recent DNA Vaccines 2012 Conference in California, United States.
Commenting on the study's initial results, Inovio head Dr J. Joseph Kim said: 'We are encouraged by preliminary phase II data showing a WT1 DNA vaccine's potential, administered with our novel delivery technology, to generate T cells and robust antibodies to treat leukaemia. These results follow on our recent scientific breakthrough represented by our human data showing the powerful killing effect of T cells generated by our cervical dysplasia therapeutic vaccine.'
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University of Southampton: http://www.southampton.ac.uk/
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