Multiple Myeloma Patients Needed for Trial of MDR Reverser

BOSTON—The Eastern Cooperative Oncology Group (ECOG) is seeking to enroll 360 multiple myeloma patients with relapsing or refractory disease for a study of PSC 833, a cyclosporin D analog that may be able to reverse chemotherapy resistance. The trial will randomize patients to receive PSC 833 plus standard VAD (vincristine, Adriamycin, and dexamethasone) or standard VAD alone.

Multidrug resistance (MDR) to chemotherapy treatment develops because of a mechanism within cancer cells that causes the cytotoxic drugs to be pumped out of the cells, thereby preventing the drugs from reaching toxic levels. Each year, approximately 800,000 cancer patients worldwide are unable to receive the optimal benefit of chemotherapy treatment due to MDR.

A Second Chance

“Resistance poses a significant obstacle in the treatment of multiple myeloma,” said William R. Friedenberg, MD, of the Marshfield Cancer Center, Marshfield, Wis, the lead investigation site for the study. PSC8 833, which is designed to overcome MDR, could possibly offer a second chance to patients who once responded to chemotherapy, but then had to stop because of resistance, he said. “If it works in multiple myeloma, it could also work in other cancers that develop MDR.”

In a multicenter phase I study of patients with multiple myeloma, oral PSC 833 in combination with standards doses of dexamethasone and escalating doses of vincristine and doxorubicin was well tolerated, and five of 26 patients achieved a partial response.

Endpoints of the current study will be response, overall survival, and event-free survival. Subjective responses—decrease in pain and improvement in anemia—will also be evaluated.

The Southwest Oncology Group (SWOG), Cancer and Leukemia Group B (CALGB), and National Cancer Institute of Canada’s Clinical Trials Group (NCIC CTG) are also participating in the trial.

Physicians interested in registering patients should contact the ECOG Coordinating Center in Boston at 617-632-3610. They can also contact Dr. Friedenberg in Marshfield, Wis, at 715-387-5511, to learn more about the study.