A new, targeted therapy may mean renewed hope for patients with metastatic kidney cancer, according to City of Hope researchers and colleagues.
Traditional chemotherapies have shown little success against renal cell carcinoma, the most common form of kidney cancer, so researchers recently turned to immunotherapy — harnessing the body’s immune system — to counter the disease. However, study findings in the Jan. 11 New England Journal of Medicine indicate that a targeted drug called sunitinib may be significantly more effective than current immunotherapy options.
Sunitinib is a powerful, novel therapy that targets several vulnerabilities in cancer cells — pathways involved in the growth, nourishment and spread of these cells. It belongs to the growing family of “smart” therapies symbolized by Gleevec and regarded as a key part of the future of customized cancer treatment.
Robert A. Figlin, M.D., the Arthur and Rosalie Kaplan Professor of Medical Oncology and associate director for clinical research at City of Hope, was the senior author on the study.
“Kidney cancer is a disease crying out for better treatments, and this study shows we’re now making progress,” Figlin said. “Studies of tumor biology have given us insight into how the cancer works, and where it’s vulnerable, and now we can target those pathways in more effective ways.”
Study investigators from 10 nations worked together to enroll 750 patients with previously untreated metastatic kidney cancer for the phase III randomized trial. Patients either received repeated six-week cycles of sunitinib (consisting of a daily pill for four weeks, followed by two weeks without medication) or interferon alfa injected three times a week.
Interferon alfa is a cytokine, a protein that activates the immune system. Research has shown the cytokine shrinks metastatic kidney cancer tumors in 5 to 20 percent of patients, so it has become a treatment option for those diagnosed with the disease.
In this study, researchers found that patients on sunitinib had progression-free survival twice as long as those on interferon alfa (11 months for sunitinib, compared to five months with interferon alfa). About 31 percent of patients in the sunitinib group responded to the drug, significantly higher than the 6 percent of the patients in the interferon alfa group who responded to that drug.
“Patients who took sunitinib also reported a better quality of life,” said Figlin, chair of the Division of Medical Oncology & Therapeutics Research at City of Hope.
Researchers noted that the most common form of renal cell cancer — called the clear-cell type — overexpresses many cellular receptors related to angiogenesis, the creation of blood vessels to nourish and sustain growing tumors. Sunitinib is one of several new agents that target angiogenesis, and a number already are under study to battle kidney cancer.
“We’re seeing that our increasing understanding of the molecular genetics and biology of kidney cancer is paying dividends in these new strategies against the disease,” Figlin said. “As researchers, physicians and scientists, we must keep looking for the mechanisms that make cancer work, so we can continue to develop strategies to attack it.”
