Combination therapy for RCC increases response rate

A combination of interferon alfa-2b and sorafenib (Nexavar) works better than does either drug alone in improving response in patients with renal cell carcinoma, according to a pilot study led by researchers from the Duke Comprehensive Cancer Center, Durham, NC.

Used in combination, the drugs led to significant tumor shrinkage in 33% of the 40 patients who participated in the study, and two of the patients had complete responses, the researchers reported (J Clin Oncol 2007; 25:3288-95). Study participants all had stage IV renal cell carcinoma.

Researchers gave study patients sorafenib in a pill form twice daily and interferon alfa-2b via injection three times a week for 8-week cycles. If the patient’s tumor had not grown or had shrunk after 8 weeks, the cycle would be repeated after a 2-week break until the tumors disappeared or until the cancer got worse.

“We found that by combining a drug that enlists the immune system’s help in combating cancer with one that cuts off a tumor’s blood supply, we could substantially increase patients’ response rates to treatment,” said lead investigator Jared Gollob, MD. “Most tumors that respond to either therapy alone begin growing again after about 5 or 6 months. By using interferon alfa-2b and sorafenib in combination, we not only increased the response rate, but found we could double the amount of time that these patients could survive without their tumors growing.”

A multi-site confirmatory trial is planned to determine whether patients show additional progress with increasing doses of sorafenib alone after achieving maximum tumor shrinkage with the dual therapy, Dr. Gollob said.