For almost two decades, researchers have been testing the effects of the measles virus on cancer cells. In that time, they have come up with huge strides in the way of making virus therapy treatments a possibility and have backed up their research with legitimate results in both test animals and humans. Read on to discover the history and science behind measles virotherapy.
2001 saw one of the first medical trials of the measles virus on cancer. Mayo Clinic Cancer Center researchers injected two types of lymphoma cells into mice, waited for them to cause tumors, and then injected the virus directly into these tumors. As a result, the tumor growth slowed or stopped, and in some cases the existing tumors shrank. This remained the case as the scientists added large doses of anti-measles antibodies. The fact that the virus therapy worked in spite of the antibodies was significant, considering the majority of humans have had the measles vaccine and are thus immune to the virus. This research paved the way for the future of virotherapy, as executives approved a trial on humans as a result of this study.
In 2005, the first human trial of measles against lymphatic cancer was published by the American Society of Hematology. In this study, they injected the vaccine directly into the tumor as they did on the mice. They also gave each patient anti-measles antibodies, but for a different reason than before; rather than attempting to find the limits of the treatment’s success, the researchers were attempting to prevent uncontrollable spread of the measles virus in the patients. The research had limited success, as the study concluded only two of the five participants saw reduced tumor lesions. Only one of the treated lesions completely disappeared, but both of the two successful patients had reduction in non-injected lesions as well.
Years later, in May of 2014, Stacy Erholtz made headlines as the first cancer patient to go into complete remission as a result of the measles treatment. She was diagnosed with myeloma–a blood cancer which spreads to bone marrow–in 2004. Many common treatments such as radiation and chemotherapy did not affect her diagnosis. As ten years of treatments passed and hope dwindled, she signed up for a measles study under Dr. Stephen Russell, a Mayo Clinic doctor who was the first person to begin researching measles in this capacity in the late 1990s. Erholtz and one other patient each received 100 billion units of the measles virus. For reference, a typical measles vaccine contains only 10,000 of these units. In the first 36 hours after the injection, Erholtz experienced intense fever, headaches, and vomiting. Afterwards, though, her tumors began to shrink, and they continued to shrink until they fully disappeared. Now, five years later, she is still alive and cancer-free.
“I was prepared to die, and I didn’t die” said Stacy Erholtz, who is pictured above. (Source)
Unfortunately, no other patient has been completely cured, including the second patient in Russell’s 2014 trial. However, doctors are still hopeful. Today, they know virus cells bind to the cancer cells and begin replicating themselves, which overpowers the pre-existing cancer. This result destroys tumor tissue. Russell and his somewhat-recently founded research company Vyriad also recognizes the uniqueness of Erholtz’s condition. They believed the treatment worked on her because her immune system did not contain antibodies against the virus due to multiple stem cell transplants, a conclusion that contradicts previous research. Also, when she got the measles injection, her myeloma had just begun to rapidly resurface following one of these transplants. Thus, the amount of cancer cells in her body was somewhat smaller than usual.
Nevertheless, Vyriad has not given up hope. They have continued to research virotherapy, both specifically for myeloma and for other cancers. Currently, their focus lies on vesicular stomatitis virus (VSV) instead of measles, as VSV does not plague North America and thus no Americans have been vaccinated against it. Their VSV trials follow in the footsteps of successful research from many other organizations, who have shown positive results in several types of cancers. For Vyriad in particular, they are focusing their VSV therapy research on T-cell lymphoma and colorectal cancer. Although they are still waiting for another success story, Russell and Vyriad are reportedly inspired by Erholtz’s wish to know other people who have responded to virotherapy. “[Erholtz] wants other people alongside her who are responding [to viral therapy],” says Russell, “so everything is about bringing that on.”