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An estimated 11,000 people die from multiple myeloma, a cancer of the white blood cells found in bone marrow, each year in the United States. In a new clinical study researchers cured that cancer in one patient by giving her a mega-dose of measles vaccine.
Does this mean they cured cancer?
There are many forms of cancer that respond differently to different treatments; this is just one case of one kind of cancer. Even as far as multiple myeloma goes, the treatment is not likely to work in all patients. But this is a promising step forward for myeloma patients, especially those for whom other traditional therapies have failed.
How does the measles treatment work?
The key here is that the measles vaccine contains a very weak version of active measles virus. The concept that viruses can be used to kill cancer in humans isn't new, but it requires more research to become a mainstream therapy. The virus binds selectively to cancer cells, using those cells as hosts for replication. This eventually destroys the cancer cells. Measles isn't the only virus used for this kind of therapy; different cancers will be more susceptible to different viruses.
Usually when this therapy is attempted, the virus is injected at the tumor site. Myeloma isn't isolated to tumors, though; the cancer also infects bone marrow itself. In this study, the vaccine was injected into the bloodstream, instead of directly into the tumor.
And this isn't your garden-variety measles vaccine. The vaccine formulation used in this study contained 100 billion infectious units — 10,000 times the standard dose. And compared to cancer treatments that last months, this measles vaccine therapy only requires a one-time dose. "What we're really excited about with this particular approach is that we believe it can become a single-shot cure," said Dr. Stephen J. Russell, lead author on the study.
One problem with this treatment is that the immune system can actually get in the way, since people in developed nations are vaccinated against measles in early childhood. Here, it's actually helpful that cancer weakens the immune system. The treatment may not be as effective in people who were exposed to the virus and already have many antibodies against it. By the same logic, the treatment only works once; a second round of therapy wouldn't work because the patient's body would recognize the virus and attack it.
What happened with patients in the study?
The treatment was given to two different patients; one experienced full remission of the cancer. The first myeloma patient — a 50-year old mother from Minnesota — had suffered from multiple relapses of the cancer and had exhausted her treatment options. The vaccine therapy, though, was a resounding success: after one shot, without any supplemental treatment, her tumors shrank and her bone marrow cleared.
Her remission lasted for nine months; she later had a local relapse with one tumor. That relapse was successfully treated with radiation.
The treatment was less successful in a second patient, who had tumors in her leg and pelvis. The researchers were able to deduce that the virus infected the patient's tumors, which became painful and began to shrink. Unfortunately, those rapidly regrew, suggesting this therapy won't work in all myeloma cases.
Were there any adverse effects from the treatment?
The patient who experienced a full remission suffered from a terrible headache while the vaccine was being administered. "We had to stop the infusion and give her Benadryl, but she soldiered on with it," Dr. Russell said. "It was quite scary because she was the first person to encounter such a significant side effect." For a few days following the treatment, she also suffered from fever and chills.
Not a terrible trade-off for complete cancer remission.
Who is affected by multiple myeloma?
There are no known causes, though research suggests that genetic abnormalities might play a role. It tends to affect older individuals; most people who develop the cancer are diagnosed in their mid-60s. The cancer can cause problem with a patients bones and kidneys. It can also decrease immunity, making them more vulnerable to infections. The five-year survival rate for myeloma is only about 45 percent.
What's next?
This study is reason for optimism, but findings from two patients can't be called definitive. The treatment needs to undergo large randomized controlled trials, the gold standard in research. The Mayo Clinic expects to launch one of these trials by September.
