Virus Vaccine Wipes Out Woman’s Cancer
Researchers evaluate oncolytic virotherapy in myeloma patients
In a proof-of-principle trial, Mayo Clinic researchers have demonstrated that virotherapy — destroying cancer with a virus that infects and kills cancer cells but spares normal tissues — can be effective in patients with multiple myeloma. The new findings were published in the Mayo Clinic Proceedings.
Two patients in the study received a single intravenous dose of an engineered virus (MIV-NIS) that is selectively toxic to myeloma plasma cells. Both patients responded, showing reductions in both bone-marrow cancer and myeloma protein. One patient, a 49-year-old woman, experienced the complete remission of myeloma and has been clear of the disease for more than 6 months, according to the authors.
“This is the first study to establish the feasibility of systemic oncolytic virotherapy for disseminated cancer,” said lead author Stephen Russell, MD, PhD. “These patients were not responsive to other therapies and had experienced several recurrences of their disease.”
In their article, the researchers explained that they reported on these two patients because they were the first two studied at the highest possible dose, had limited previous exposure to measles (and therefore fewer antibodies to the virus), and had no remaining treatment options.
Oncolytic virotherapy — using re-engineered viruses to fight cancer — has a history dating back to the 1950s. Thousands of cancer patients have been treated with oncolytic viruses from many different virus families, including herpesviruses, poxviruses, and common cold viruses. However, the new study provides the first well-documented case of a patient with disseminated cancer experiencing complete remission at all disease sites after virus administration.
The second patient in the paper, whose cancer did not respond as well to the virus treatment, was equally noteworthy because her imaging studies provided proof that the intravenously administered virus specifically targeted the sites of tumor growth. The imaging assessments were possible only because the virus had been engineered with a “snitch gene” — an easily identifiable marker — so researchers could accurately determine its location in the body.
More of the MV-NIS therapy is being manufactured for a larger, phase II trial. The researchers also want to test the effectiveness of the virotherapy in combination with radioactive treatment (iodine-131) in a future study.