Heidelberg, Germany, 25 June 2002
Highly promising results from clinical trials indicate that alpha-emitting radioisotopes can kill cancer cells. A recent workshop in Heidelberg organised by ITU, Deutsches Krebsforschungszentrum (DKFZ) and the Universities of Düsseldorf and Heidelberg gathered European, American and Australian researchers who presented this innovative therapy.
Alpha-immunotherapy should develop into an effective treatment over the next few years and provide new methods of healing for patients. How does the cancer-killing mechanism work? A cancer-cell selective vehicle, (e.g. a monocolonal antibody or a peptide) is connected to a powerful radioactive isotope. As it radioactively decays, the isotope emits particles that can either directly or indirectly kill any cancer cells it encounters.
"More research is needed," said EU Research Commissioner Philippe Busquin, "but experts tell us that the results from pre-clinical and first clinical trials are promising."
"Search-and-destroy isotopes should be helpful in fighting a great number of cancers such as leukae-mia, lymphoma (haematological malignancies), microscopic, intraperitoneally growing cancers (e.g. ovarian, stomach), glioblastoma and post-operative treatment of glioma, melanomas, colon tumours, myeloma and palliative treat-ment of malignant ascites.
"Multi-disciplinary co-operations between Europe's best teams are needed to advance this innovative approach. Cancer is a key priority in the EU's next research programme, to be launched later this year."
Currently only a few organisations, including the Institute for Transuranium Elements (ITU) in Karlsruhe that is part of the JRC, are able to produce the required isotopes and participants (including private companies) have discussed the possible development needed to improve availability of the radio elements for hospitals.
Both the recent results obtained in clinical studies, using bismuth-213 to combat acute mye-loid leukaemia, and the first evaluations of the direct use of actinium-225, point to the right direction.
Whereas the first isotope emits only one alpha particle during its decay, the latter has a decay chain with 4 alpha particles and could be much more efficient, at least when its full potential can be exploited. At the highest dosage level used (up to100 mCi bismuth-213), no acute toxicity was observed. This breakthrough opens the way for accepting the analyses of other alpha-emitters in a clinical setting also.
The Commission has supported pioneering work at the Deutsches Krebsforschungszentrum (DKFZ) and the Kantonspital of Basel, where the first patients were treated for Non-Hodgkin's lymphoma and glioblastoma respectively. To date, 37 patients in the US have been treated with bismuth 213 or astatine 211 and 11 patients in Europe.
Other very promising studies on treating melanoma using local antibody conjugated bismuth-213 injection foster scientific understanding and several hypotheses on the operating mechanisms of alpha-damage can therefore be validated. As the use of highly radiotoxic al-pha- emitting isotopes is not currently common practice in hospitals, strict requirements need to be respected to allow the large-scale application of this technology..State-of-the art genomics and proteomics are expected to provide a sound understanding of the governing processes in the application of alpha-emitters and other radioactive isotopes.
Such details will help not only in combating cancer, but also in understanding how low-level radiation exposure effects the human genetic makeup. The hope is to produce a patient-tailored drug and/or therapy design in the future, through studying the specific features of particular diseases and their genetic expression.
Joint Research Centre
Joint Research Centre