Experimental vaccine shows early promise against mesothelioma

In collaboration with Adfero

A vaccine against mesothelioma, a cancer associated with exposure to asbestos, has shown early promise in its first clinical trial.

The experimental vaccine is an example of dendritic cell (DC)-based immunotherapy, in which the body's own immune system is harnessed to target and destroy cancer cells.

In the vaccine, a sample of the patient's 'dendritic' immune cells are mixed with proteins taken from their tumour.

When implanted back into the patient, these cells can then activate other elements of the patient's immune system, known as T-cells, and encourage them to attack and destroy the tumour.

Researchers at Erasmus Medical Center in The Netherlands have previously shown that DC vaccines bring about an anti-tumour response in mice and decided to test the technique in humans.

They enrolled ten people who had recently been diagnosed with a form of mesothelioma called 'malignant pleural' mesothelioma, and who had been previously treated with chemotherapy.

The team took a sample of dendritic cells from each patient's blood, and exposed them to proteins from their tumours.

The dendritic cell samples were also exposed to a 'marker' protein called keyhole limpet hemocyanin (KLH).

Patients then received three injections of their 'activated' dendritic cells over a two-week period.

Publishing their findings in the American Journal of Respiratory and Critical Care Medicine, the researchers revealed that all ten patients had antibodies to the KLH marker in their blood, confirming that the vaccines had brought about an immune response.

Further tests on four of the patients' tumours revealed that three of the tumours had got smaller, although this could not be conclusively or directly linked to the vaccine.

The researchers noted that eight out of ten patients developed flu-like symptoms after being vaccinated, but that all but one had recovered from these symptoms within 24 hours. There were no other serious side-effects.

Dr Joachim Aerts, a pulmonary physician at Erasmus Medical Center, revealed that the study is the first to investigate DC-based immunotherapy in patients with mesothelioma.

"The possibility to harness the potency and specificity of the immune system underlies the growing interest in cancer immunotherapy," he said. "One such approach uses the patient's own DC to present tumour-associated antigens and thereby generate tumour-specific immunity."

Dr Aerts added: "We hope that by further development of our method it will be possible to increase survival in patients with mesothelioma and eventually vaccinate persons who have been in contact with asbestos to prevent them from getting asbestos-related diseases."

Dr Jodie Moffat, health information manager at Cancer Research UK, said: "This study involved just ten people, and so much more research and testing is needed before we'll know if this will be a viable and effective treatment for mesothelioma in the future. Mesothelioma can be very difficult to treat, so finding new treatments to help beat the disease is crucial."

References

  • Hegmans, J. et al (2010). Consolidative Dendritic Cell-Based Immunotherapy Elicits Cytotoxicity Against Malignant Mesothelioma American Journal of Respiratory and Critical Care Medicine DOI: 10.1164/rccm.200909-1465OC