The paper has reported on a new study in the growing field of virotherapy – a treatment where viruses are used to attack diseases.
The study was a proof of concept study, involving people with multiple myeloma – a type of cancer that affects plasma cells, which are made in bone marrow. The cancerous cells are usually spread throughout the bone marrow, but can also form tumours.
The article reports on two women who were given an infusion of a high dose of a modified measles virus that could specifically recognise the myeloma cells. The researchers wanted the virus to infect and kill the cancerous cells, but leave the normal cells untouched.
Six weeks after treatment, both women had no cancerous cells. One of the women also had all of the solid tumour clumps in her body shrink within six weeks of starting the treatment, with the effect appearing to last over a nine-month period. One of her tumours showed some signs of growth at nine months, meaning that more treatment (radiotherapy) was required.
The other woman showed some improvement in her tumours at six weeks, but not as much.
Both women experienced quite severe side effects in the immediate aftermath of the treatment, such as a rapid heartbeat, but these abated within a week.
The researchers are now planning a phase II trial, involving a larger group of patients.
Where did the story come from?
The study was carried out by researchers from the Mayo Clinic in the US. It was funded by the National Institutes of Health and National Cancer Institute, alongside other individuals and charitable foundations. The Mayo Clinic and some of the researchers declared a financial interest in the technology being tested.
The study was published in the peer-reviewed medical journal Mayo Clinic Proceedings.
While the overall reporting of the study was accurate, the Daily Mirror and the Mail Online don’t appear to know the difference between a “cure” and “remission”.
Complete remission means that any signs and symptoms of the cancer are undetectable; however, the cancer can return.
While one of the woman did experience complete remission for nine months, she did require some additional treatment. Patients in remission still need to be monitored long term to see if the cancer returns.
What kind of research was this?
This was a preliminary report of two patients taking part in a phase I clinical trial, which aimed to test the effects of a modified measles virus created to treat multiple myeloma – a type of blood cancer. There has been increasing interest in using the process of modifying viruses as a form of cancer treatment. Preliminary research has shown some effect in solid tumours, such as malignant melanoma (the most serious type of skin cancer), but this method hasn’t been tested in patients with blood cancer.
Phase I trials are used to test the maximum safe dose of a new treatment, and is done on a small number of patients. They also allow researchers to get an idea of what effect the treatment has on the disease. If the treatment is safe and shows signs of being effective, it will then go on to larger-scale trials to confirm these effects, and to see what proportion of patients could experience these.
What did the research involve?
The researchers gave the two female patients with multiple myeloma the modified measles virus through a gradual infusion into their blood stream, over the course of an hour. They then monitored the women in various ways to see the effects.
The researchers used a modified form of the measles virus, which was developed from the weakened strain of the virus that is used in measles vaccines. The virus was also genetically modified to take up a radioactive form of the chemical iodine, which allowed the researchers to monitor its spread in the body. The modified virus recognises and binds to a protein that is found at high levels on the surface of human myeloma cells. This allows the virus to enter these cells and kill them.
The two patients tested received the highest dose of the modified virus. They were both women, aged 49 and 65. Their disease had not responded to multiple rounds of chemotherapy, and therefore had a high risk of dying. Neither woman had been exposed to the natural measles virus before.
After receiving the virus, the women were monitored to see if they experienced any adverse effects. The researchers also monitored how much the virus had spread through the body. Finally, they looked at what effect it had on the cancerous cells in bone marrow and the clumps of cancerous tissue throughout the body.
What were the basic results?
During and shortly after the infusion, the women experienced various side effects, including fever, low blood pressure and a rapid heartbeat. One woman also experienced a severe headache, nausea and vomiting. The side effects were treated and went away within a week, and both women developed antibodies against the measles virus. When tracking the virus, the researchers saw that it was concentrated in the clumps of cancerous tissue (lesions) and not spreading to the normal tissues.
Six weeks after the treatment, biopsies found no abnormal (cancerous) cells in the bone marrow of either woman. Both women also showed a reduction in proteins in the blood that are normally raised in people with multiple myeloma. In one woman, this reduction was maintained over a six-week period, but the levels seen in the other woman increased again six weeks after the treatment.
Six weeks after the treatment, there was substantial shrinkage of the five known lesions found in one of the women’s bodies– some of the lesions had almost disappeared. Six months after treatment, scans suggested that only one of the lesions might be growing, and this was still the case at the nine-month mark. The woman had radiotherapy to treat just this lesion, as her bone marrow biopsies still appeared normal.
The second woman showed that some of her lesions had shrunk six weeks after treatment, with one disappearing. However, most of the lesions continued to grow.
How did the researchers interpret the results?
The researchers concluded that both patients showed a response to the modified measles virus treatment, and one patient showed lasting, complete remission at all disease sites. They suggest that this type of virus treatment offers a promising new way to target and destroy blood cancers that are spread throughout the body.
Conclusion
This research has shown that a modified measles virus can produce a long-term remission of cancerous lesions in a person with multiple myeloma that has not responded to chemotherapy.
Patients such as this have limited remaining treatment options, so a new treatment would offer an important development.
The article describes the response of two women in a phase I trial who received the highest dose of the virus. One of the women had a lasting response; the other woman showed some signs of an early response, but these were not as good and were not as long-lasting.
As yet, we don’t know what proportion of patients might respond to this treatment, or if certain types of patients benefit more than others. The report focuses on two women with a disease that is particularly hard to treat and who received the highest doses.
It does not describe what happened to the remaining people in the phase I trial, in terms of either the side effects or effects on the disease. The full results will be published elsewhere.
The other patients may not have had responses that were as impressive, particularly as some of them received lower doses of the virus.
Phase I trials focus on safety of different doses of a treatment and allow an early glimpse of what beneficial effects patients might have. This study shows that the modified measles virus treatment seemed acceptably safe and can produce a response in multiple myeloma.
The researchers now plan to go on to a larger phase II trial, which will allow them to better assess what proportion of patients might benefit, what these benefits are and how long this effect might last.
Source: NHSinform.co.uk
