Thalidomide shows promise for ovarian cancer treatment
Thalidomide was banned in 1962 after scores of women who took the anti-nausea medication early in their pregnancies delivered babies with severe birth defects.
But by the 1990s, researchers had discovered that the drug is effective in treating some blood cancers and malignant brain tumors.
Those results intrigued U of M cancer researcher Levi Downs, who treats women with ovarian cancer. Since an ovarian cancer trial using thalidomide had not been done yet, Downs decided to start one.
His randomized trial included 37 women who received a chemotherapy drug called topotecan. Twenty-eight others took topotecan and thalidomide.
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"In the patients that took the thalidomide with topotecan, there was a response rate of 50 percent, compared to a response rate of 22 percent in the patients that took just the topotecan," says Downs.
In this study, response rate means the drug therapies reduced or got rid of the cancer for a period of time. Downs says the results are significant enough to suggest that thalidomide makes a real difference in treating ovarian cancer.
He suspects it works in two important ways in the body.
"We know that it decreases the expression of various chemicals in the body that stimulate blood vessels. So it prevents the tumor from making new blood vessels," Downs says.
Without new blood vessels, the tumor can't sufficiently feed new cells, so the cancer can't grow.
In addition, Downs says the drug might also boost the body's own defenses.
"Thalidomide acts on many different levels in the immune system, and perhaps stimulates the body's immune system to help it fight cancer as well," says Downs. "And that's likely playing a role in its reduction of cancer cells also."
It gives you hope, and time with your family, which are really important.
Downs didn't have enough patients in his study to show if thalidomide actually prolonged survival. He did detect a trend of four additional months of life for the women who took the thalidomide. Still, he says the difference is not considered statistically significant based on his low patient numbers.
While it's not a cure, Downs says, he concluded that thalidomide improved the quality of life for those patients who took it.
"We did see a statistically significant difference in progression-free survival, meaning time off of chemotherapy, which is a very important thing in recurrent ovarian cancer," says Downs. "Any time that we can buy off of chemotherapy is of potential benefit, if it improves a patient's quality of life."
Study participant Bonnie Lemke agrees. She didn't receive any thalidomide, and received the chemotherapy drug instead. It put her cancer into remission for about seven weeks.
Lemke says she was a little disappointed that she didn't receive thalidomide. She doesn't know if it would have given her a longer remission. But she says with ovarian cancer, even a few extra days or weeks is a big deal.
"It gives you hope, and time with your family, which are really important," says Lemke. "It's like leaving memories, because even though you know it might not be getting rid of the cancer, it's managing it enough to give you more time."
Lemke says she used her remission time last summer to spend an entire week with each of her seven grandchildren. Since then, she's tried three other types of chemotherapy to stay ahead of her cancer.
Ovarian cancer specialists are watching Dr. Down's thalidomide trials with interest.
Dr. William Cliby, a gynecological oncologist at Mayo Clinic in Rochester, says many of his colleagues believe that drugs like thalidomide, that impede cancer without poisoning the patient, are the wave of the future in cancer therapy.
Cliby says he doesn't want to overstate Downs' results. But he thinks the findings are significant, considering that Downs treated patients in late-stage ovarian cancer.
"So if you can see a benefit in that group, we often get hopeful that if we move it up earlier in the course of treatment, rather than at the end of the line for patients, that we have a much better chance of seeing a bigger improvement," says Cliby.
Dr. Levi Downs is in the midst of a second national ovarian cancer trial using a drug that's a variation of Thalidomide. He hopes to have results from that study by this summer.
His current findings were released at the Society of Gynecologic Oncologists' annual meeting in Palm Springs, California.
