Thalidomide shows potential in fight against ovarian cancer

The drug, which gained notoriety in the early 1960s for causing birth defects, may help control the fifth most common cancer among women

Levi Downs, Jr., is a professor and gynecologic oncologist at the Medical School and Cancer Center and principal investigator for the study.

To hear an audio vignette on thalidomide and the research of Downs, go to the University of Minnesota Moment. U of M Moments are daily radio vignettes featuring University experts commenting on timely issues.

By Deane Morrison

Published on November 8, 2005

The drug thalidomide gained notoriety during the early 1960s, when its use to prevent morning sickness was linked to severe birth defects. Now, in a study led by a University researcher, thalidomide has shown promise in treating recurrences of ovarian cancer, the fifth most common cancer among women.

What makes this cancer so insidious is its habit of spreading undetected, often to the abdominal lining, before the cancerous ovary is discovered and removed. These cells can keep coming back after treatment, turning the cancer into a chronic disease. New options are needed when the cancer resists standard treatments, says Levi Downs, Jr., the principal investigator for the study. Downs, an assistant professor and gynecologic oncologist at the Medical School and Cancer Center, presented the study last week at the XXIII Chemotherapy Foundation Symposium in New York.

The study evaluated 69 women with recurrent cancer, who were randomly assigned to receive either a combination of thalidomide and the anti-cancer drug topotecan or topotecan alone. The patients had been previously treated for epithelial ovarian cancer, a form of the disease that originates in the epithelium, or lining, of the ovary and accounts for 80 percent of ovarian cancers. It was the first such study with thalidomide, which already had been shown effective against multiple myeloma, a cancer of the bone marrow.

"I was surprised at how effective the treatment was," says Downs. "We didn't expect such great results."

When the results came in, patients receiving thalidomide and topotecan showed a 47 percent rate of response to treatment, while those who received topotecan alone showed a 21 percent response. (Responses consisted of shrinkage or disappearance of tumors or a return to normal of blood tests for a protein called CA-125, high levels of which are associated with ovarian cancer.) In some patients, the response was complete: The cancer disappeared from 32 percent of patients treated with the combination therapy versus 16 percent for the topotecan-alone group.

"I was surprised at how effective the treatment was," says Downs. "We didn't expect such great results."

In addition, of the patients who saw a complete disappearance of cancer, those who had received thalidomide plus topotecan had an average of six cancer-free months before the disease returned, versus four months for the topotecan-alone group.

"This means an extra two months without chemotherapy. That's huge for a patient," says Downs. The combined treatment did not cure the cancer, but the study indicates that thalidomide could broaden treatment options for physicians, he says.

Downs is now the principal investigator in a new trial of the drug Revlimid, which is chemically similar to thalidomide but has fewer side effects. Like the thalidomide-topotecan study, the new trial will be carried out at multiple centers nationwide. The researchers are now seeking patients and hope to enroll 70.

This year in the United States, about 25,000 women will be diagnosed with ovarian cancer and about 16,000 will die from it. About 78 percent of patients survive a year after diagnosis, and more than 50 percent survive five years.

The study was sponsored by Celgene Corp., which manufactures thalidomide, and involved cancer centers in Minnesota, Ohio, South Dakota, and California.