"Both women also had limited previous exposure to measles, and therefore fewer antibodies to the virus, and essentially had no remaining treatment options."
Washington, May 16 - A 49-year-old US woman with advanced bone marrow cancer called multiple myeloma is effectively cancer-free after receiving an experimental trial that injected her a single dose of an engineered measles vaccine, a study said.
The patient, with tumors all over her body, including a three-cm-diametre one on her forehead, experienced complete remission of myeloma and has been clear of the disease for over six months, Xinhua reported citing the study published in Mayo Clinic Proceedings.
A second patient, a 65-year-old woman, did not respond as well to the virus treatment that is selectively toxic to myeloma plasma cells, researchers said.
However, high-tech imaging studies provided a clear proof that the intravenously administered virus specifically targeted the sites of tumor growth.
The researchers said the trial is a proof of concept that virotherapy, destroying cancer with a virus that infects and kills cancer cells but spares normal tissues, can be effective against the deadly cancer multiple myeloma.
This is the first study to establish the feasibility of systemic oncolytic virotherapy for disseminated cancer, Mayo Clinic hematologist Stephen Russell, first author of the paper and co-developer of the therapy, said in a statement.
These patients were not responsive to other therapies and had experienced several recurrences of their disease.
Virotherapy has a history dating back to the 1950s, according to the Mayo Clinic, and thousands of cancer patients have been treated with a host of various viruses.
However, this study provides the first well-documented case of a patient with disseminated cancer having a complete remission at all disease sites after virus administration.
It was noted that both patients were studied at the highest possible dose of the therapy.
Both women also had limited previous exposure to measles, and therefore fewer antibodies to the virus, and essentially had no remaining treatment options.
The researchers said their next step is to see if the measles vaccine works in a larger number of patients. They also want to test the effectiveness of the virotherapy in combination with radioactive therapy in a future study.