A patient from the Isle of Wight with the blood cancer multiple myeloma has become the first person in the world to receive a new form of radiotherapy which targets cancer cells without damaging healthy organs. In a clinical trial funded by Leukaemia Research, Pauline Pain has received a much higher dose of radioactivity delivered accurately to the bone marrow than would otherwise have been possible.
High doses of radioactivity are needed to completely eradicate cancer cells in the bone marrow. This cannot be risked with standard treatments such as total body irradiation, which cause “collateral damage” to healthy tissues, specifically the liver, and may be fatal. The new treatment uses a radioactive isotope attached to an antibody that specifically targets a protein present on myeloma tumour cells in the bone marrow.
Pauline Pain, age 58, from the Isle of Wight is the first person to be treated in the clinical trial, which is assessing the effect of the new radiotherapy treatment on patients with myeloma – an as yet incurable bone marrow cancer that causes extensive bone damage and a failure of the bone marrow to make healthy blood cells.
Following the new targeted radiotherapy treatment, Pauline was able to return home to await her bone marrow transplant (BMT). Conventional total body irradiation would have meant a long stay in hospital.
Pauline says: “The only side-effects of the radiotherapy were a little temporary tiredness and mild sickness; other than that I felt very, very well. It was incredible to be walking around knowing that something inside me was fighting the cancer, but I couldn’t feel it at all”.
Dr Kim Orchard, senior lecturer in the University of Southampton’s School of Medicine, who is leading the trial at Southampton General Hospital explains: "Radiotherapy is used to clear the bone marrow of myeloma cells before a stem cell transplant. Current treatment uses high doses of radiation, which are delivered by X-rays but the sensitivity of healthy organs limits the dose that can be tolerated. “
“Previous attempts to use antibodies to deliver the radioactivity have been frustrated by their accumulation in the liver, lungs and kidneys, which can cause serious complications and may be fatal. The key to this promising new treatment is that the antibody only accumulates in the bone marrow and not in other tissues.”
The new type of radiotherapy works by delivering the radio-isotope Yttrium-90 attached to an antibody which targets a protein called CD-66, found on the surface of bone marrow cells and myeloma tumour cells. The radioactive Yttrium-90 delivers radiation specifically to sites of disease in the bone marrow and as a result, destroys the bone marrow and any tumour cells. This is followed by a transplant of healthy stem cells collected from the patient at an earlier time.
Dr Orchard said: “The early results using this new approach to bone marrow transplantation are very encouraging with high doses of radiation targeted to the bone marrow without any side-effects. We are currently using the targeted radiation in addition to chemotherapy and we hope that the trial will show a clear benefit in better and longer remissions from myeloma. If we are successful, then this approach offers great promise for the treatment of patients who need a bone marrow transplant for a range of other blood cancers such as leukaemia.”
Dr David Grant, Scientific Consultant at Leukaemia Research, said: “This trial is very exciting. One of the main reasons why stem cell transplants have been less successful in the long-term treatment of myeloma is that patients are not cleared of all the cancer cells before the transplant. This new radiotherapy is not only more effective and potentially cheaper than existing treatments, it is far less toxic for the patient. It also enables patients to go home immediately after the procedure, reducing time spent in hospital.”
(Source: Leukaemia Research: January 2009)