Trabectedin shows promise for ovarian cancer

Women with recurrent ovarian cancer can be helped by an experimental therapy using a drug already touted for its ability to fight other cancers, a finding that provides hope for improved treatment of this deadly disease.

Dr. Bradley Monk, a UC Irvine gynecologic oncologist who led the worldwide phase III clinical trial, said trabectedin is the most recent addition to a short list of active drug therapies for recurrent ovarian cancer. He presents study results Sept. 15 at the 33rd Congress of the European Society for Medical Oncology in Stockholm.

"These are exciting results because positive trials in recurrent ovarian cancer are rare and have almost always led to federally approved treatments," said Monk, an associate professor who studies and treats ovarian cancers at the Chao Family Comprehensive Cancer Center at UC Irvine. "This treatment undoubtedly will be evaluated carefully by the U.S. Food and Drug Administration and, if approved, will give women with ovarian cancer another much needed option."

Phase III studies are multicenter trials on large patient groups designed to be the definitive assessment of a drug's effectiveness. Such a study is often the last step before a drug is reviewed by a regulatory agency like the FDA for approval as a safe, effective treatment.

In this trial, an international group of researchers treated 672 women whose ovarian cancer had progressed after first-line treatment. Half the women received a combination therapy of trabectedin and a chemotherapy drug called pegylated liposomal doxorubicin. The other half received the chemotherapy drug alone, which is standard treatment in these cases.

In patients on the combination therapy, researchers found no progression of the cancer for an average of 7.3 months, as compared to 5.8 months for those treated with the single drug. For those who had relapsed more than six months after the first-line therapy, the median progression-free time was 9.2 months for the combination treatment, as compared to 7.5 months for the other patients.

Under the brand name Yondelis, trabectedin is approved in Europe and South Korea for treating advanced soft tissue sarcoma. In addition to the phase III ovarian cancer trial, it is being studied in smaller, phase II trials for prostate, breast and pediatric cancers.

Trabectedin is a synthetic version of a compound isolated from the sea squirt, a tubular sea animal used in a number of medical studies. It binds to the DNA of a cancer cell and blocks its ability to multiply, thus killing the cells and shrinking tumors.

When ovarian cancer is detected early - when it is confined to the ovaries - more than 90 percent of women will live at least five years, according to the American Cancer Society. Only about 20 percent of cases are detected that early. If the cancer is detected after it has spread, only about 30 percent of women survive five years. Each year, approximately 20,000 American women are diagnosed with ovarian cancer and about 15,000 die of the disease.