Study shows virotherapy promising against multiple myeloma

Volume 3, Issue 3, 2014

Summary

Mayo Clinic documents case of a patient with complete remission after virus administration.

Photograph of Stephen J. Russell, M.D., Ph.D., hematologist, Mayo Clinic Cancer Center

Stephen J. Russell, M.D., Ph.D.

Mayo Clinic Cancer Center researchers have demonstrated that oncolytic virotherapy — destroying cancer with a re-engineered virus that infects and kills cancer cells but spares normal tissues — can be effective against multiple myeloma.

The results of a proof-of-principle clinical trial were published online May 13, 2014, in the journal Mayo Clinic Proceedings.

In the study, two patients with multiple myeloma received a single intravenous dose of an engineered measles virus (MV-NIS) that is selectively toxic to myeloma plasma cells.

Both patients responded to the virus treatment, showing reduction of both bone marrow cancer and myeloma protein. One patient, a 49-year-old woman, experienced complete remission of her multiple myeloma and was clear of the cancer for more than six months.

"This is the first study to establish the feasibility of systemic oncolytic virotherapy for disseminated cancer," said Mayo Clinic Cancer Center hematologist Stephen J. Russell, M.D., Ph.D., first author of the paper and co-developer of the therapy. "These patients were not responsive to other therapies and had experienced several recurrences of their disease."

In their article, the researchers explain 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 has a history dating back to the 1950s. Thousands of cancer patients have been treated with oncolytic viruses from many different virus families, including herpes viruses, pox viruses and common cold viruses.

However, this study provides the first well-documented case of a patient with widespread cancer having a complete remission after virus administration.

The second patient in the paper, whose cancer did not respond as well to the virus treatment, was equally remarkable, the researchers said, because her imaging studies provided clear proof that the intravenously administered virus specifically targeted the sites of tumor growth.

These high-tech imaging studies were possible only because the virus had been engineered with a so-called snitch gene — an easily identifiable marker — that enabled researchers to accurately determine its location in the body.

More of the MV-NIS therapy is being manufactured for a larger, phase II clinical trial. The researchers also want to test the effectiveness of the virotherapy in combination with radioactive therapy (iodine 131) in a future study.