In the trial, which only involved two patients, scientists administered 100 billion units (around 10 million vaccines' worth) of a special measles strain that had been specifically engineered to target cancer cells. In 50-year-old Stacy Erholtz — whose myeloma had spread to tumors all over her body and in her bone marrow — the virus caused a headache, followed by vomiting, followed by a 105-degree fever.
A few days later, Erholtz began to notice that a tumor in her forehead was shrinking. Over the next few weeks, all the tumors throughout her body dissolved, and her cancer was in remission.
The treatment worked because of the tendency of viruses to bind to cancer cells and co-opt them as hosts. Eventually, the tumors explode, releasing more of the virus into the bloodstream. Then, the patient's immune system steps in to attack the cancer cells that have been marked by the virus. As the Star Tribune reports, "Antiviral vaccines that have been rendered safe can produce the same effects and can also be modified to carry radioactive molecules to help destroy cancer cells without causing widespread damage to healthy cells around the tumors."
The technique of fighting cancer with a virus has been around since the 1950s. However, this marks the first time this sort of treatment, called oncolytic virotherapy, has produced such dramatic results. The researchers attribute their success to the high dose of the virus, as well as the fact that Erholtz hadn't received the measles vaccine, which meant that her body didn't already have antibodies to fight the virus. But, they also point out that this method could be effective even in patients who've been vaccinated against measles — provided their immune systems are broken down prior to treatment.
Of course, this isn't the miracle cure many are claiming it to be — yet. The trial involved only two participants, and while it worked for Erholtz, the treatment failed to produce lasting results in the second patient. The next step is large-scale, randomized clinical trials to see if Erholtz's results can be replicated in patients with other types of cancers.
Nevertheless, scientists are excited at the prospect of a powerful, yet poetically simple, new way to fight cancer. As the trial's lead researcher, Stephen Russell, told the Washington Post: "It’s a very important landmark because now we know it can happen. It’s a game changer. And I think it will drive a development in the field.” (Washington Post)